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, an Arabic prince of Batan in Mesopotamia, was a celebrated astronomer, about the year 880, as appears by his observations. He is also called Muhammed ben Geber Albatani (Mahomet, the son of Geber) and Muhamedes Aractensis. He made astronomical observations at Antioch, and at Racah or Aracta, a town of Chaldea, which some authors call a town of Syria or of Mesopotamia. He is highly spoken of by Dr. Halley, as a man of great acuteness, and accuracy in making observations. Finding that the tables of Ptolemy were imperfect, he computed new ones, which were long used as the best among the Arabs: these were adapted to the meridian of Aracta or Racah. He composed in Arabic a work under the title of “The Science of the Stars,” comprizing all parts of astronomy, according to his own observations and those of Ptolemy. The original of this, which has never been published, is in the library of the Vatican. It was translated into Latin by Plato of Tibur, and was published at Nuremberg in 1537, with some additions and demonstrations of Regiomontanus; and the same was reprinted at Bologna in 1645, with this author’s notes. Dr. Halley detected many faults in these editions. (Philos. Trans, for 1693, No. 204.) In this work Albategni gives the motion of the sun’s apogee since Ptolemy’s time; as well as the motion of the stars, which he makes one degree in seventy years. He made the longitude of the first star of Aries to be 18 2‘; and the obliquity of the ecliptic 23 35’; and upon his observations were founded the Alphonsine tables of the moon’s motion.

, or Abou-Machar, a noted Arabian astrologer and philosopher, was born at Balkh in the Khorasan, about the year 805 or 806. For a long time he was addicted to the Mahometan traditions, and a determined enemy to philosophy; but in his forty-seventh year he began to study the sciences, and acquired the reputation of an astronomer and astrologer; and, although he is now principally known by his writings on astrology, he cannot be refused a place among the most distinguished easterns, who have made astronomical observations. The table called Zydj Abou-Machar was calculated from his observations; but the work from which he derives his principal reputation, is his treatise on astrology, entitled “Thousands of years;” in which, among other singular positions, he maintains that the world was created when the seven planets were in conjunction in the first degree of Aries, and will end when they shall assemble in the last degree or Pisces. He died in 885. His astrological work was published at Venice, 1506, 8vo; with the title “De magnis conjunctionibus, annorum revolutionibus, ac eorum perfectionibus;” but his “Introductio ad Astronomiam” was printed before this in 4to,. Augsburgh, 1489; and reprinted at Venice, 1490, 1506, and 1515, 4to.

, Alfergani, or Fargani, was a celebrated Arabic astronomer, who nourished about the year 800. He was so called from the place of his nativity, Fergan, in Sogdiana, now called Maracanda, or Samarcand, anciently a part of Bactria. He is also called Ahmed (or Muhammed) Ben-Cothair, or Katir. He wrote the Elements of Astronomy, in 30 chapters or sections. In this work the author chiefly follows Ptolomy, using the same hypotheses, and the same terms, and frequently citing him. There are three Latin translations of Alfragan’s work. The first was made in the twelfth century, by Joannes Hispalensis; and was published at Ferrara in 1493, and at Nuremberg in 1537, with a preface by Melancthon. The second was by John Christman, from the Hebrew version of James Antoli, and appeared at Francfort in 1590. Christman added to the first chapter of the work an ample commentary, in which he compares together the calendars of the Romans, the Egyptians, the Arabians, the Persians, the Syrians, and the Hebrews, and shews the correspondence of their years.

, caliph of Bagdat, a philosopher and astronomer in the beginning of the ninth century, ascended the throne in the year 814. He was the son of Harun-AlRashid, and the grandson of Almanzor. His name is otherwise written Mamon, Almaon, Almamun, Alamoun, or Al-Maimon. Having been educated with great care, and with a love for the liberal sciences, he applied himself to cultivate and encourage them in his own country. For this purpose he requested the Greek emperors to supply him with such books on philosophy as they had among them; and he collected skilful interpreters to translate them into the Arabic language. He also encouraged his subjects to study them; frequenting the meetings of the learned, and assisting in their exercises and deliberations. He caused Ptolemy’s Almagest to be translated in the year 827; and in his reign, and doubtless by his encouragement, an astronomer of Bagdat, named Habash, composed three sets of astronomical tables. Almamon himself, however, made many astronomical observations, concerning the obliquity of the ecliptic, and caused skilful observers to procure proper instruments to be made, and to exercise themselves in such observations. Under his auspices also a degree of the meridian was measured; and he revived the sciences in the East so successfully that many learned men were found, not only in his own time, but after him, in a country where the study of the sciences had long been forgotten. This learned king died near Tarsus in Cilicia, by having eaten too freely of dates, on his return from a military expedition, in the year 833, in the 48th or 49th year of his age.

, king of Leon and Castile, who has been surnamed The Wise, on account of his attachment to literature, is now more celebrated for having been an astronomer than a king. He was born in 1203, succeeded his father Ferdinand III. in 1252, and died in 1284, consequently at the age of 81. The affairs of the reign of Alphonsus were very extraordinary and unfortunate, but we shall here only consider him in that part of his character, on account of which he has a place in this work, namely, as an astronomer and a man of letters. He acquired a profound knowledge of astronomy, philosophy, and history, and composed books upon the motions of the heavens, and on the history of Spain, which are highly commended. “What can be more surprising,” says Mariana, “than that a prince, educated in a camp, and handling arms from his childhood, should have such a knowledge of the stars, of philosophy, and the transactions of the world, as men of leisure can scarcely acquire in their retirements? There are extant some books of Alphonsus on the motions of the stars, and the history of Spain, written with great skill and incredible care.” In his astronomical pursuits he discovered that the tables of Ptolemy were full of errors, and was the first to undertake the task of correcting them. For this purpose, about the year 1240, and during the life of his father, he assembled at Toledo the most skilful astronomers of his time, Christians, Moors, or Jews, when a plan was formed for constructing new tables. This task was accomplished about 1252, the first year of his reign; the tables being drawn up chiefly by the skill and pains of Rabbi Isaac Hazan, a learned Jew, and the work called the Alphonsine Tables, in honour of the prince, who was at vast expences concerning them. He fixed the epoch of the tables to the 30th of May 1252, being the day of his accession to the throne. They were printed for the first time in 1483, at Venice, by Radtolt, who excelled in printing at that time; an edition extremely rare: there are others of 1492, 1521, 1545, &c.

, astronomer, geometrician, and mechanic, was the son of a labourer employed in agriculture. He was born Feb. 22, 1723, at Oberperfuss, a village about 12 miles from Inspruck, and died Sept. 1, 1766. While engaged in the menial employments of labourer and shepherd, he felt an irresistible impulse towards astronomy and geometry. Pere Hill, a Jesuit, professor in the university of Inspruck, discovered his talents, and enabled him to cultivate them with such success, that in a short time he became an able astronomer, and one of the best mechanics in Europe. He made a pair of globes for the university of Inspruck, which are acknowledged to be masterpieces in their kind. He constructed and completed a great variety of mathematical instruments, and drew maps and charts of admirable accuracy and neatness. Snatched away in the flower of his age from the arts and sciences, he was deservedly lamented by person’s of real knowledge. The empress-queen, whose subject he was, and who had granted him a pension of 200 florins, which he enjoyed but two months, settled a pension of 50 florins on his sister, to testify her consideration for the deceased. The maps which he left were published at Vienna in 1774, “Tyrolis chorographia delineata e Petro An-ich et BlasioHueber, curante Ign. Weinhart.” His life was published in German, at Munich, 1767, with a portrait.

, a Latin poet of the sixteenth century, was born at Parma, of a very ancient family, and was afterwards eminent as a physician, and a man of general literature. The volume which contains his poetry, and is very scarce, is entitled “Georgii Anselmi Nepotis Epigrammaton libri septem: Sosthyrides: Palladis Peplus: Eglogæ quatuor,” Venice., 1528, 8vo. He took the title of Nepos to distinguish himself from another George Anselme, his grandfather, a mathematician and astronomer, who died about 1440, leaving in manuscript “Dialogues on Harmony,” and “Astrological institutions.” Our author wrote, besides his poems, some illustrations of Plautus, under the title of “Epiphyllides,” which are inserted in Sessa’s edition of Plautus, Venice, 1518; and had before appeared in the Parma edition of 1509, fol. He wrote also the life of Cavicco or Cayicio, prefixed to his romance of “Libro de Peregrine,” Venice, 1526, 8vo, and 1547. He died in 1528.

, called in German Brenkwitz, a celebrated astronomer and mathematician, was born at Leisnig or Leipsic in Misnia, 1495, and made professor of mathematics at Ingolstadt in 1524, where he died in 1552, aged fifty-seven. He wrote treatises upon many of the mathematical sciences, and greatly improved them, especially astronomy and astrology, which in that age were much the same thing: also geometry, geography, arithmetic. He particularly enriched astronomy with many instruments, and observations of eclipses, comets, &c. His principal work was the “Astronomicum Caesareum,” published in folio at Ingolstadt in 1540, and which contains a number of interesting observations, with the descriptions and divisions of instruments. In this work he predicts eclipses, and constructs the figures of them in piano. In the second part of the work, or the “Meteoroscopium Planum,” he gives the description of the most accurate astronomical quadrant, and its uses. To it are added observations of five different comets, viz. in the years 1531, 1532, 1533, 1538, and 1539: where he first shows that the tails of a comet are always projected in a direction from the sun.

, a Greek poet, celebrated for his poem entitled the Phenomena, flourished about the 127th olympiad, or near 300 years before Christ, while Ptolemy Philadelphus reigned in Egypt. Being educated under Dionysius Heracleotes, a Stoic philosopher, he espoused the principles of that sect, and became physician to Antigonus Gonatus, the son of Demetrius Poliorcetes, king of Macedon. The Phenomena of Aratus gives him a title to the character of an astronomer, as well as a poet. In this work he describes the nature and motion of the stars, and shews their various dispositions and relations; he describes the figures of the constellations, their situations in the sphere, the origin of the names which they bear in Greece and in Egypt, the fables which have given rise to them, the rising and setting of the stars, and he indicates the manner of knowing the constellations by their respective situations.

, a celebrated Greek philosopher and astronomer, was a native of the city of Samos; but of what date is not exactly known; it must have been, however, before the time of Archimedes, as some parts of his writings and opinions are cited by that author, in his Arenarius: he probably, therefore, flourished about 420 years B. C. He held the opinion of Pythagoras as to the system of the world, but whether before or after him, is uncertain, teaching that the sun and stars were fixed in the heavens, and that the earth is moved in a circle about the sun, at the same time that it revolved about its own centre or axis. He taught also, that the annual orbit of the earth, compared with the distance of the fixed stars, is but as a point. On this head Archimedes says, “Aristarchus the Samian, confuting the notions of astrologers, laid down certain positions, from whence it follows, that the world is much larger than is generally imagined; for he lays it down, that the fixed stars and the sun are immoveable, and that the earth is carried round the sun in the circumference of a circle.” On which account, although he did not suffer persecution and imprisonment, like Galileo, yet he did not escape censure for his supposed impiety; for it is said Cleanthus was of opinion, that Aristarchus ought to have been tried for his opinions respecting the heavenly bodies and the earth. Aristarchus invented a peculiar kind of sun-dial, mentioned by Vitruvius. There is extant of his works only a treatise upon the magnitude and distance of the sun and moon; this was translated into Latin, and commented upon by Commandine, who first published it with Pappus’s explanations, in 1572, Pisaur, 4to. Dr. Wallis afterwards published it in Greek, with Commandine’s Latin version, in 1688, at Oxford, and which he inserted again in the third volume of his mathematical works, printed in folio at Oxford, in 1699. In 1644 was published, at Paris, a work entitled “De Mundi Systemate, cum notis Bl. P. Roberval,” 8vo, which goes under the name of Aristarchus; but it has been supposed to be a fiction.

, a very ingenious mechanic of London, who introduced several improvements in the mechanism of time-keepers, for which he received premiums from the Board of Longitude. He was the inventor of the expansion balance, and of the present detached escapement, and the first artist who ever applied the gold cylindrical spring to the balance of a time-piece. He died in the fifty-fifth year of his age, at Well-hall, near Eltham in Kent, August 25, 1799. The following publications may be consulted for an account of his improvements: “An account kept during thirteen months in the Royal Observatory at Greenwich, of the going of a Pocket Chronometer, made on a new construction by John Arnold, having his new-invented balance spring, and a compensation for the effects of heat and cold in the balance. Published by permission of the Board of Longitude,” 4to, 1780. lf A Letter from Mr. Christian Meyer, astronomer to the elector Palatine, to Mr. N. N. on the going of a new Pendulum Clock, made by Mr. John Arnold, and set up in the elector’s observatory at Manheim, translated from the German,“4to, 1781.” On the Longitude; in a letter to the Commissioners of that Board; containing remarks on the accounts given of a Clock at Manheim, and tlaat of a Pocket Chronometer at Greenwich; both made by Mr. John Arnold,“4to, 1781.” An Answer from John Arnold to an anonymous letter on the Longitude, 4to, 1782.

, or Eizarakel, a native of Toledo, in the twelfth century, was one of the most celebrated astronomers who appeared after the time of the Greeks, and before the revival of learning. He wrote a treatise on the “obliquity of the Zodiac,” which he fixed, for his time, at 23 34', and determined the apogee of the sun by four hundred and two observations. The famous Alphonsine Tables, published by order of Alphonsus, king of Castille, were partly taken from the works of Arzachel. Few particulars are known of the personal history of this astronomer, unless that he was of the Jewish persuasion. Montucla says that his tables are preserved in several libraries, in manuscript, with an introduction which explains their use.

, an able astronomer and mathematician, was born at Saorgio, near Nice, in Provence, in 1714. At the age of sixteeeri he entered the order of St. Dominic, and made rapid progress in his studies, not only in sacred literature, but in mathematics, and the languages. In his thirty-fifth year he was appointed second librarian of the Casanata, and ten years aftenvards first librarian, which office he held until his death. His studies were extended to mathematics, astronomy, antiquities, natural history, criticism, and bibliography but astronomy was his favourite pursuit, on which he published many pieces. He was appointed by the late pope Pius VI. to make mineralogical observations on the new mines of Tolfa. He died July 3, 1794. His published works are, 1. “Mercurius in sole visus, observatio habita Romae, &c.” Rome, 1753, 4to. 2. “Phenomena ccelestia observata,” Rome, 1754, 8vo. 3. “Otia astronomica,” Rome, 1755, 4to. 4. “Novissimus Mercurii transitus,” Rome, 1756, 8vo. 5. “Passaggio di Venere, &c.” 4to, without place or date, but most probably 1761. 6. “Transitus Veneris, &c.” 1762. This appears to be cither the same work as the preceding, or a Latin translation. 7. “Investigatio Parallaxis Solaris, &c.” Rome,. 1765, 8vo, published under the anagrammatical name of Dadeus Ruffus. 8. “De Solis Parallaxi commentarius,” Rome, 1766, 8vo. 9. “Dimostrazione della theoria, &c.” of the Comet of the year 1769, published in a literary journal at Rome, 1770. 10. “Letere typografiche,” under the name of the abbe Nicolas Ugolini de Foligno, addressed to Xavier Laire, author of the historical essay on the Roman typography of the 15th century, Mentz, 1778, 8vo, a satirical attack on father Laire. 11. “Catalogus historico-criticus Romanarum editionum saeculi 15.” Rome, 1783, 4to. 12. “Catalogus librorum typis impressorum bibliothecae Casanatensis, praestantioribus notis et observationibus illustratus,” 4 vols. fol. 1762, 1768, 1775, 1788. 13. “Specimen historico-criticum editionum Italicarum ssGCuli 15,” Rome, 1794, 4to. In some of the foreign journals, are other essays by him on astronomical subjects.

was a French astronomer, and a picmber of the old academy of France, into which he was received in 1666. He is principally known for having brought to perfection the micrometer, an instrument usually fitted to a telescope, in the focus of the objectglass, for measuring small angles or distances. This he published in 1666, but Mr. Townley, in the Philosophical Transactions, claims it for one of our countrymen, Mr. Gascoigne. He relates that from some scattered letters and papers of this gentlemen, who was killed in the grand rebellion, he had learned that before its breaking out, he had invented a micrometer, of as much effect as that made by M. Auzout, and had made use of it for some years not only in taking the diameters of the planets, and distances upon land, but in determining other matters of nice importance in the heavens, as the moon’s distance, &c. Mr. Gascoigne’s instrument also fell into the hands of Mr. Townley, who says farther, that by the help of it he could make above 40,000 divisions in a foot. The French writers endeavour to deny all this, and conclude with an assertion, as illiberal as it is false, that every nation has a zeal for its literary glory, but that in England alone this zeal is pushed to ardour and to injustice. Auzout, however, was an astronomer of acknowledged abilities. He died in 1691.

, an eminent French astronomer, was born in Paris, Sept. 25, 1736. His father was the fourth in succession of his family who followed the profession of a painter and young Bailly was also destined to painting, and had already made some progress in the art, when he showed a decided inclination for the study of the belles-lettres. Poetry was the first object that engaged his attention he even produced some tragedies which were praised by Lanoue, not however without advising his young friend to attend rather to science and Lacaille essentially contributed to direct his attention to the study of Natural Philosophy accordingly, in the year 1762, he presented to the academy “Observations on the Moon,” which Lacaille had made him draw up with all the particularity of detail required* by the new state of astronomy, and which were quoted by him with approbation, in the sixth volume of the Ephemerides.

, an eminent physician and astronomer, born in 1582, at Ashby de la Zouch, Leicestershire, was educated at the public school of that town; and from thence went to Emanuel college in Cambridge, under the tuition of Dr. Joseph Hall, afterwards bishop of Norwich. When he had taken his degrees of bachelor and master of arts, he went, back to Leicestershire, where he taught a grammar-school for some years, and at the same time practised physic. He employed his leisure hours in the mathematics, especially astronomy, which had been his favourite study from his earliest years. By the advice of his friends, who thought his abilities too great for the obscurity of a country life, he removed to London, where he was admitted a fellow of the college of physicians. His description of the comet, which appeared in 1618, greatly raised his character. It was by this means he got acquainted with sir Henry Savile, who, in 1619, appointed him his first professor of astronomy at Oxford. Upon this he removed to that university, and was entered a master commoner of Merton college; the master and fellows whereof appointed him junior reader of Linacer’s lecture in 1631, and superior reader in 1635. As he resolved to publish correct editions of the ancient astronomers, agreeably to the statutes of the founder of his professorship; in order to make himself acquainted with the discoveries of the Arabian astronomers, he began the study of the Arabic language when he was above 40 years of age. Some time before his death, he removed to a house opposite Merton college, where he died in 1643. His body was conveyed to the public schools, where an oration was pronounced in his praise by the university orator; and was carried from thence to Merton college church, where it was deposited near the altar. His published works are, 1. “An astronomical description of the late Comet, from the 18th of November 1618, to the 16th of December following,” London, 1619, 4to. This piece was only a specimen of a large work, which the author intended to publish in Latin, under the title of “Cometographia.” 2. “Procli sphæra. Ptolomæi de hypothesibus Planetarum liber singularis.” To which he added Ptolemy’s “Canon regnorum.” He collated these pieces with ancient manuscripts, and has given a Latin version of them, illustrated with figures, 1620, 4to. 3. “Canicularia; a treatise concerning the dog-star and the canicular days.” Published at Oxford in 1648, by Mr. Greaves, together with a demonstration of the heliacal rising of Sirius, or the dog-star, for the parallel of Lower Egypt. Dr. Bainbridge undertook this work at the request of archbishop Usher, but left it imperfect; being prevented by the breaking out of the civil war, or by death.

, a Scotch astronomer in the sixteenth century, whose writings have deservedly transmitted his memory to posterity, was the son of the laird of Bassantin in the Merse, and born some time in the reign of king James IV. He was sent while young to the university of Glasgow where, instead of applying himself to words, he studied things; and, while other young men of his age were perfecting themselves in style, he arrived at a surprising knowledge, for that time, in almost all branches of the mathematics. In order to improve himself in this science, and to gratify his passion for seeing other countries, he travelled, soon after he quitted the college of Glasgow, through the Netherlands, Switzerland, Italy, and Germany, fixing himself at last in France, where he taught the mathematics with applause, in the university of Paris. He fell in there with the common notions of the times, and was either credulous enough to entertain a good opinion of judicial astrology, or had so much address as to make the credulity of others useful to him, by supporting an erroneous system, then in too great credit for him to demolish, if he had been disposed, as the humour of believing such kind of predictions never ran so strong as at this time, nor any where stronger than in that country. At last, having a desire to see his relations, and spend his remaining days in his own country, he resolved to quit France, where he had acquired a high reputation, and some fortune, and returned home in the year 1562. It was doubtless to our author that sir James Melvil alludes in his Memoirs, when he says that his brother, sir Robert, while he was using his endeavours to reconcile the two queens, Elizabeth and Mary, met with one Bassantin, a man learned in the high sciences, who told him “that all his travel would be in vain; for, said he, they will never meet together: and next, there will never be anything but dissembling and secret hatred, for a while; and at length, captivity and utter wreck to our queen from England.” He added, “that the kingdom of England at length shall fall, of right, to the crown of Scotland; but it shall cost many bloody battles; and the Spaniards shall be helpers, and take a part to themselves for their labour.” A prediction in which Bassantin partly guessed right, which it is likely he was enabled to do from a judicious consideration of probable circumstances and appearances.

It does not at all appear in what manner he spent the remainder of his life after he came back to Scotland; but it is certain he did not survive long, since his decease happened, as those who were well acquainted with him attest, in 1568. As to his learning, we are told by those who admired it most, it lay not in languages, of which, except his mother-tongue, he knew none thoroughly, though he spoke and taught in French, but in a very incorrect manner, and wrote much worse. He had very clear notions in most parts of his writings, and was far from being a contemptible astronomer, though the commendations bestowed on him by some authors very far surpass his deserts. He was too nauch tinctured with the superstition of the times, not to intermix a vast deal of false, and even ridiculous matter in his writings, on the virtuous aspects, and influences of the planets; yet in other respects he shews much good sense and industry, which render his works worth reading, and ought to secure both them and his memory from oblivion. As to his religion, he is reported to have been a zealous Protestant; and, with regard to his political principles, he is said to have adhered to the famous earl of Murray, then struggling for that power which he afterwards obtained. The works published by our author were: 1. “Astronomia, Jacobi Bassantini Scoti, opus absolutissimum,” &c. in which the observations of the most expert mathematicians on the heavens are digested into order and method, Latin and French, Geneva, 1599, fol. 2. “Paraphrase de l‘Astrolabe, avec une amplification de l’usage de l'astrolabe,” Lyons, 1555; and again at Paris, 1617, 8vo. 3. “Super mathematica genethliaca;” i. e. of the calculation of nativities. 4. “Arithmetical” 5. “Musica secundnm Platonem.” 6. “De Mathesi in genere.” The very titles of his works, joined to the age in which he flourished, sufficiently justify his right to a place in this work; and, though he might have foibles, yet, without doubt his practical skill was great, and the pains he took contributed not a little to bring in that accuracy and correctness in observations, which have effectually exploded those superstitions to which, with other great men, he was too much addicted.

was a German lawyer and astronomer of the latter part of the sixteenth and beginning of the seventeenth century, but in what particular year or place he was born, is not certainly known; however, his name will be ever memorable in the annals of astronomy, on account of that great and excellent work which he first published in 1603, under the title of “Uranometria,” being a complete celestial atlas, or large folio charts of all the constellations, with a nomenclature collected from all the tables of astronomy, ancient and modern, with the useful invention of denoting the stars in every constellation by the letters of the Greek alphabet, in their order, and according to the order of magnitude of the stars in each constellation. By means of these marks, the stars of the heavens may, with as great facility, be distinguished and referred to, as the several places of the earth are by means of geographical tables; and as a proof of the usefulness of this method, our celestial globes and atlasses have ever since retained it; and hence it is become of general use through all the literary world; astronomers, in speaking of any star in the constellation, denoting it by saying it is marked by Bayer, a, or ft, or y, &c.

, a member of the national Institute of France, and an astronomer of considerable fame, was born at Vesoul, June 29, 1752. He was originally intended for the church, and in 1767, entered the order of the Bernardines, but his turn for astronomy induced him to become the pupil of Lalande, and one of the ablest of his scholars. His uncle Miroudat, bishop of Babylonia, having-appointed him his vicar-general, he left France in 1781, to exercise the functions of that office in the Levant, and at the same time to take astronomical observations. He went first to Aleppo, thence to Bagdad, Bassora, and Persia. On the eve of the revolution, he returned to France, after having contributed very essentially to the promotion of the sciences of astronomy and geography, as may appear by his communications in the “Journal deaf Savans” for 1782, 1784, 1785, 1787, 1788, and 1790. He remained with his family until 1795, when the then French government appointed him consul at Mascate, a Portuguese settlement in Arabia; but in 1797, we find him at Constantinople, whence he sailed along the Black Sea, making many observations, and rectifying many errors in the charts of that sea. When Bonaparte was appointed commander of the expedition to Egypt, he recalled Beauchamps from Mascate, and added him to the number of scientific men attached to the army. In 1799, Bonaparte sent him on a secret mission to Constantinople, but before he had proceeded far from the port of Alexandria, he was taken by the English, and delivered up to the grand Turk as a spy. By the intercession, however, of the ambassadors of Spain and Russia, his punishment was mitigated to imprisonment in a strong castle on the borders of the Black Sea, and in 1801 he was released. Bonaparte, then first consul, appointed him mercantile commissary at Lisbon, but before he could reach this place, he died at Nice, Nov. 19, 1801, to the great regret of his friends, and particularly of the learned world.

This wonderful discovery has not escaped the notice of contemporary writers. A confirmation of it occurs in the Latin chronicle of Hartman Schedl, and in the remarks made by Petrus Mateus on the canon law, two years before the expedition of Columbus. These passages demonstrate that the first discovery of America is due to the Portuguese, and not to the Spaniards; and that the chief merit belongs to a German astronomer. The expedition of Frederick Magellan, which did not take place before the year 1519, arose from the following fortunate circumstance: This person being in the apartment of the king of Portugal, saw there a chart of the coast of America, drawn by Behem, and at once conceived the bold project of following the steps of our great navigator. Jerome Benzon, who published a description of America in 1550, speaks of this chart; a copy of which, sent by Behem himself, is preserved in the archives of Nuremberg. The celebrated astronomer Riccioli, though an Italian, yet does not seem willing to give his countryman the honour of this important discovery. In his “Geographia Reformata,” book III. p. 90, he says, “Christopher Columbus never thought of an expedition to the West Indies until his arrival in the island of Madeira, where, amusing himself in forming and delineating geographical charts, he obtained information from Martin Bcehm, or, as the Spaniards say, from Alphonsus Sanchez de Huelva, a pilot, who had chanced to fall in with the islands afterwards called Dominica.” And in another place, “Boehm and Columbus have each their praise they were both excellent navigators but Columbus would never have thought of his expedition to America, had not Bcehm gone there before him. His name is not so much celebrated as that of Columbus, Americus, or Magellan, although he is superior to them all.”

, a French mathematician and astronomer, was born at Lyons, March 5, 1703, entered among the Jesuits, and became professor of humanity at Vienne and at Avignon, and of mathematics and philosophy at Aix. In 1740 he was invited to Lyons and appointed professor of mathematics, director of the observatory, and keeper of the medals and the same year he became astronomer to the academy, the memoirs of which are enriched by a great many of his observations, particularly that on the passage of Mercury on the Sun, May 6, 1753, during which he saw and demonstrated the luminous ring round that planet, which had escaped the notice of all the astronomers for ten years before. In all his results, he entirely agreed with Lalande, who had made the same observations at Paris, and with the celebrated Cassini. All his observations, indeed, are creditable to his talents, and accord with those of the most eminent astronomers. Among his other papers, inserted in the memoirs of the academy, we find several on vegetation, on the evaporation of liquids, and the ascent of vapours, on light, a physical theory on the rotation of the earth and the inclination of its axis, &c. In meteorology, he published observations on the tubes of thermometers, with an improvement in the construction of them, which was the subject of three memoirs read in the academy of Lyons in 1747. He has also endeavoured to account for metals reduced to calcination weighing heavier than in their former state, and maintains, against Boyle, that fire is incapable of giving this additional weight, and likewise refutes the opinion of those who attribute it to air, or to substances in the air which the action of fire unites to the metal in fusion. This memoir was honoured with the prize by the academy of Bourdeaux in 1747, and contained many opinions which it would have been difficult to contradict before the experiments of Priestley, Lavoisier, and Morveau. In 1748, he received the same honour, from that academy, for a paper in which he maintained the connexion between magnetism and electricity, assigning the same cause to both. In 1760, he received a third prize from the same academy, for a dissertation on the influences of the moon on vegetation and animal oeconomy. Beraud was also a corresponding member of the academy of sciences in Paris, and several of his papers are contained in their memoirs, and in those of the academy of Lyons. He wrote several learned dissertations on subjects of antiquity. On the dissolution of the society of Jesuits, he left his country for some time, as he could not conscientiously take the oaths prescribed, and on his return, notwithstanding many pressing offers to be restored to the academy, he preferred a private life, never having recovered the shock which the abolition of his order had occasioned. In this retirement he died June 26, 1777. His learning and virtues were universally admired he was of a communicative disposition, and equal and candid temper, both in his writings and private life. Montucla, Lalande, and Bossu, were his pupils and father Lefevre of the Oratory, his successor in the observatory of Lyons, pronounced his eloge in that academy, which was printed at Lyons, 1780, 12mo. The Dict. Hist, ascribed to Beraud, a small volume, “La Physique des corps animus,” 12mo.

, a celebrated chemist and natural philosopher, was born March 20, 1735, at Catharineberg in Westgothland. His father was receiver-gene^ ral of the finances, and had destined him to the same employment but nature had designed him for the sciences, to which he had an irresistible inclination from his earliest years. His first studies were confined to mathematics and physics, and all efforts that were made to divert him from science having proved ineffectual, he was sent to Upsal with permission to follow the bet of his inclination. Linnaeus at that time filled the whole kingdom with his fame. Instigated by his example, the Swedish youth flocked around him; and accomplished disciples leaving his school, carried the name and the system of their master to the most distant parts of the globe. Bergman, struck with the splendour of this renown, attached himself to the man whose merit had procured it, and by whom he was very soon distinguished. He applied himself at first to the study of insects, and made several ingenious researches into their history; among others into that of the genus of tenthredo, so often and so cruelly preyed on by the larvae of the ichneumons, that nestle in their bowels and devour them. He discovered that the leech is oviparous, and that the coccus aquaticus is the egg of this animal, from whence issue ten or twelve young. Linnæus, who had at first denied this fact, was struck with astonishment when he saw it proved. “Vidi et obstupui” were the words he pronounced, and which he wrote at the foot of the memoir when he gave it his sanction. Mr. Bergman soon distinguished himself as an astronomer, naturalist, and geometrician; but these are not the titles by which he acquired his fame. The chair of chemistry and mineralogy, which had been filled by the celebrated Wallerius, becoming vacant by his resignation, Mr. Bergman was among the number of the competitors and without having before this period discovered any particular attention to chemistry, he published a memoir on the preparation of alum, that astonished his friends as well av his adversaries but it was warmly attacked in the periodi­^cal publications, and Wallerius himself criticised it without reserve. The dispute, we may suppose, was deemed of high importance, since the prince Gustavus, afterwards king of Sweden, and then chancellor of the university, took cognizance of the affair, and after having consulted two persons, the most able to give him advice, and whose testimony went in favour of Bergman, he addressed a memorial, written with his own hand, in answer to all the objections urged against the candidate, to the consistory of the university and to the senate, who elected him agreeably to his highness’s wishes.

, a learned critic and astronomer, was born at Perry St. Paul, commonly called Pauler’s Perry, near Towcester in Northamptonshire, the 2d of May 1638. He received some part of his education at Northampton but his father dying when he was very young, his mother sent him to an uncle in London, who entered him at Merchant-taylors-school, in 1648 here he continued tillJune 1655, when he was elected scholar of St. John’s college in Oxford, of which also he became afterwards fellow. DuTing his stay at school, he had accumulated an uncommon fund of classical learning, so that when he went to the university, he was a great master of the Greek and Latin tongues, and not unacquainted with the Hebrew. He had also previously acquired a good Latin style, could compose verses well, and often used to divert himself with writing epigrams, but he quitted these juvenile employments when at the university, and applied himself to history, philology, and philosophy, and made himself master of the Hebrew, Syriac, Arabic, and Coptic. He applied himself next to the mathematics, under the famous Dr. J. Wallis. He took the degree of B. A. Feb. the 12th, 1659 that of master, April 16, 1662 and that of B. D. June 9, 1668. Decem,ber following he went to Leyden, to consult several Oriental manuscripts left to that university by Joseph Scaliger and Levinus Warner, and especially the 5th, 6th, and 7th books of Apollonius Pergieus’s conic sections; the Greek text of which is lost, but which are preserved in the Arabic version of that author. This version had been brought from the East by James Golius, and was in the possession of his executor, who, pleased that Mr. Bernard’s chief design in coming to Holland was to examine this manuscript, allowed him the free use of it. He accordingly transcribed these three books, with the diagrams, intending to publish them at Oxford, with a Latin version, and proper commentaries; but was prevented from completing this design. Abraham Echellensis had published a Latin translation of these books in 1661, and Christianus Ravius gave another in 1669: but Dr. Smith remarks, that these two authors, though well skilled in the Arabic language, were entirely ignorant of the mathematics, which made it regretted that Golius died while he was preparing that work for the press; and that Mr. Bernard, who understood both the language and the subject, and was furnished with all the proper helps for such a design, was abandoned by his friends, though they had before urged him to. undertake it. It was, however, at last published by Dr. Halley in 1710.

, the grandson of the preceding John, was born at Basil Nov. 4, 1744, and died at Berlin July 13, 1807. He studied at Basil and Neufchatel, attaching himself chiefly to philosophy, mathematics, and astronomy. At the age of nineteen, he was invited to the place of astronomer in the academy of Berlin, and some years after, having obtained permission to travel, he visited Germany, England, and France, and in his subsequent travels, Italy, Russia, Poland, &c. From the year 1779, he resided at Berlin, where he was appointed head of the mathematical class of the academy. He was also a member of the academies of Petersburg^ and Stockholm, and of the royal society of London. Like all the other branches of his family, he was a laborious writer. The following are the principal productions of his pen, 1. “Recueil pour les Astronomes,” 1772 76, 3 vols. 8vo. 2. “Lettres sur diflPerents sujets, ecrites pendant le cours d‘un voyage par PAllemagne, la Suisse, la France meridionale, et I’ltalie,in 1774 and 1775,” 3 vols. 8vo. 1777—79. 3. “Description d'un Voyage en Prusse, en Russie, et en Pologne, en 1777 et 1778,” first published in German, 1779, 6 vols. but afterwards in French, Warsaw, 1782. 4. “Lettres Astronomiques,” 1781, according to our authority but he published a work under this title about 1772, after he had made a literary excursion in 1768 to England, France, and Germany, containing his observations on the actual state of practical astronomy at Gottingen, Cassel, and other parts of Germany, and at Greenwich, Oxford, Cambridge, London, and Paris. 5. “A collection of voyages,” in German, 16 vols. 1781—1785. 6. “The Archives, or records of History and Geography,” in German, 8 vols. 1783 1788. 7. “De la reforme politique des Juifs,” translated from the German of Dohm, 1782, 12mo. 8. “Elemens d‘Algebre d’Euler,” from the German, Lyons, 1785, 2 vols. 8vo. 9. “Nouvelles litteraires de divers pais,” Berlin, 1776 79, 8vo. He edited also, in conjunction with professor Hindenburg, for three years, the “Mathematical Magazine,” and wrote many papers in the Memoirs of the Berlin Academy, and the Astronomical Ephemerides, published in Berlin.

, a very learned Italian astronomer and philosopher, was born at Verona, Dec. 13, 1662. After being instructed in the elements of education in his own country, he removed to Bologna, where he went through a course of rhetoric and three years of philosophy, in the Jesuits’ college. He afterwards studied mathematics and design, and made a great progress in both. In 1680 he removed to Padua, where he studied divinity, and was admitted to the degree of doctor. His master in mathematics and natural philosophy was the learned Montanari, who became much attached to him, and bequeathed to him his collection of mathematical instruments. At Padua Bianchini learned also anatomy, and, with rather more pleasure, botany. His inclination being for the church, he went next to Rome, where he was kindly received by cardinal Peter Ottoboni, who knew his family, and appointed him his librarian. Here, as was usual for persons with his views, he went through a course of law, but without losing sight of his favourite studies, experimental philosophy, mathematics, and astronomy. He was admitted a member of the physico-mathematical academy, established by Ciampini, and read many learned papers at their sittings.

, a Swedish astronomer, was born about the middle of the seventeenth century. He became professor of mathematics at Upsal in 1679, but his zeal for the Cartesian system made him be considered as a dangerous innovator, and he might have been a serious sufferer from the prejudices raised against him, if he had not met with a kind protector in Charles XL This prince having travelled to Torneo, was so struck with the phenomena of the sun at the spring solstice, that he sent Biilberg and Spola to make observations on it, in the frontiers of Lapland, and their observations were confirmed by those of the French mathematicians sent thither by Louis XV. Under king Charles’s protection, Biilberg received considerable promotion, and having studied divinity, was at last made bishop of Strengnes. 'He died in 1717, leaving, 1. “Tractatus de Cometis,” Stockholm, 1682. 2. “Elementa Geometrices,” Upsal, 1687. 3. “Tractatus de refractione solis inoccidui,” Stockholm, 1696. 4. “Tractatus de reformatione Calendarii Juliani et Gregoriani,” Stockholm, 1699, and many other philosophical and theological dissertations.

In 1727, at the age of twenty-nine, he obtained the prize proposed by the academy of sciences, for the best way of masting of ships. This first success of Bouguer was soon after followed by two others of the same kind; he successively gained the prizes of 1729 and 1731; the former, for the best manner of observing at sea the height of the stars, and the latter, for the most advantageous way of observing the declination of the magnetic needle, or the variation of the compass. In 1729, he gave an “Optical Essay upon the Gradation of Light;” a subject quite in which he examined the intensity of light, and determined its degrees of diminution in passing through different pellucid mediums, and particularly that of the sun in traversing the earth’s atmosphere. JVIairati gave an extract of this first essay in the Journal des Savans, in 1730. In this same year, 1730, he was removed from the port of Croisic to that of Havre, which brought him into a nearer connection with the academy of sciences, in which he obtained, in 1731, the place of associate geometrician, vacant by the promotion of Maupertuis to that of pensioner; and in 1735 he was promoted to the office of pensioner-astronomer. The same year he was sent on the commission to South America, along with messieurs Godin, Condamine, and Jeussieu, to determine the measure of the degrees of the meridian, and the figure of the earth. In this painful and troublesome business, of ten years duration, chiefly among the lofty Cordelier mountains, our author determined many other new circumstances, beside the main object of the voyage such as the expansion and contraction of metals and other substances, by the sudden and alternate changes of heat and cold among those mountains; observations on the refraction of the atmosphere from the tops of the same, with the singular phenomenon of the sudden increase of the refraction, when the star can be observed below the line of the level; the laws of the density of the air at different heights, from observations made at different points of these enormous mountains; a determination that the mountains have an effect upon a plummet, though he did not assign the exact quantity of it; a method of estimating the errors committed by navigators in determining their route; a new construction of the log for measuring a ship’s way; with several other useful improvements. Other inventions of Bouguer, made upon different occasions, were as follow: the heliometer, being a telescope with two object-glasses, affording a good method of measuring the diameters of the larger planets with ease and exactness: his researches on the figure in which two lines or two long ranges of parallel trees appear his experiments on the famous reciprocation of the pendulum and those upon the manner of measuring the force of the light &c. &c.

September 1641, he quitted Geneva, after having spent one-and-twenty months in that city; and, passing through Switzerland, and the country of the Grisons, entered Lombardy. Then, taking his route through Bergamo, Brescia, and Verona, he arrived at Venice; where having made a short stay, he returned to the continent, and spent the winter at Florence. Here he employed his spare hours in reading the modern history in Italian, and the works of the celebrated astronomer Galileo, who died at a village near this city during Mr. Boyle’s residence in it. It was at Florence that he acquired the Italian language; which he understood perfectly, though he never spoke it so fluently as the French. Of this indeed he was such a master, that, as occasion required, he passed for a native of that country in more places than one during his travels.

Among the other great works, which by this means he gained time to finish, there is reason to believe, that one was a collection of elaborate processes in chemistry; concerning which he wrote a letter to a friend, which is still extant; but the piece itself was never published, though we read in the letter, “that he left it as a kind of hermetic legacy to the studious disciples of that art.” Besides these papers, committed to the care of one whom he esteemed his friend, he left also very many behind him at the time of his death, relating to chemistry; which, as appears by a Jetter directed to one of his executors, he desired might be inspected by three physicians whom he named, and that gome of the most valuable might be preserved. “Indeed,” says the writer of his life, “it is highly reasonable to suppose, that many important discoveries were contained in them; chemistry being his favourite study, and opening to him perpetually such a new scene of wonders, as easily persuaded him of the possibility of transmuting metals into gold. This persuasion of his is evident from several parts of his writings, and was avowed by himself to the great Dr. Halley, the lateroyal astronomer, who related to me his conversation with him upon that subject. And it was probably in consequence of this opinion, that he took so much pains to procure, as he did in August 1689, an act for the repeal of a statute made in the fifth year of king Henry IV. against the multiplying of gold and silver.”

It appears that thus early in life he had many friends; and it is probable that by some of them he might have risen to eminence in the church, had not his natural inclination led him to pursue other studies, in which he afterwards shone so conspicuously. He received his first rudiments of the mathematics from his uncle Dr. James Pound, who resided at his living of Wanstead in Essex, where our astronomer was some time curate: this gentleman was his mother’s brother, a man of singular capacity and genius, and eminent as a divine, a physician, and a mathematician. In the two former capacities he went to the East-Indies in the company’s service; and was one of those who had the good fortune to escape from the massacre of the factory, on the island of Pulo Condore, in Cochin China. An account of this shocking scene remains amongst Dr. Bradley’s papers, written by Dr. Pound, together with a journal kept by him on board the Rose sloop, until, after many difficulties* and distresses, they arrived at Batavia the 18th of April 1705. The public suffered much in this catastrophe, by the loss of Dr. Pound’s papers, and other valuable curiosities collected by him, which all perished in the conflagration; as he had no time to save any thing but his own life. With this relation, to whom he was dear even more than by the ties of blood, he spent all his vacations from other duties: it was whilst with him at Wanstead, that he first began the observations with the sector, which led to his future important discoveries.

On the death of John Keill, M. D. he was chosen Savilian professor of astronomy in Oxford, Oct. 31, 1721. On this promotion, so agreeable to his taste, he resigned the living of Bridstow, and also the sinecure of Landewy Welfry, and henceforward devoted his time and studies to his beloved science; nor was he sooner known, than distinguished by the friendship of lord Macclesfield, sir Isaac Newton, his colleague in the Savilian professorship, Dr. Halley, and other great mathematicians, astronomers, and patrons of science. In the course of his observations, which were innumerable, he discovered and settled the laws of the alterations of the fixed stars, from the progressive motion of light, combined with the earth’s annual motion about the sun, and the nutation of the earth’s axis, arising from the unequal attraction of the sun and moon on the different parts of the earth. The former of -these effects is called the aberration of the fixed stars, the theory of which he published in 1727; and the latter the nutation of the earth’s axis, the theory of which appeared in 1737: so that in the space of about 10 years, he communicated to the world two of the finest discoveries in modern astronomy; which will for ever make a memorable epoch in the history of that science. In 1730, he succeeded Mr. Whiteside, as lecture-reader of astronomy and experimental philosophy in Oxford: which was a considerable emolument to himself, and which he held till within a year or two of his death, when the ill state of his health made it necessary to resign it. At the decease of Dr. Halley, he was appointed astronomical observator at the royal observatory at Greenwich, February 3, 174-1-2. From letters found amongst his papers, it appears that Dr. Halley was very desirous that our astronomer should succeed him; and in one letter, when he found himself declining, he desires his leave to make interest for him: but he owed this new acquisition chiefly to the friendship of lord Macclesfield, the late president of the royal society. Upoa this promotion he was honoured with the degree of doctor of divinity, by diploma from Oxford.

In 1747, he published his Letter to the earl of Macclesfield, concerning an apparent motion observed in some of the fixed stars; on account of which he obtained the annual gold prize-medal from the royal society. It was in consequence of the royal society’s annual visit to the observatory at Greenwich, during which he represented to them the necessity of repairing the old instruments, &c. that in 1748 George II. by his sign manual, directed to the commissioners and principal officers of his navy, ordered the payment of 1000 to James Bradley, D. D. his astronomer, and keeper of the royal observatory, in order to repair the old instruments in the said observatory, and to provide new ones. This enabled him to furnish it with the noblest and most accurate apparatus in the known world, suited to the 'dignity of the nation and the royal donor: in the executive part of this useful work, those eminent artists, Mr. George Graham and Mr. Bird, deserve honourable mention, who contributed much towards the perfection of those instruments, which enabled Dr. Bradley to leave behind him the greatest number of the most accurate observations that were perhaps ever made by any one man. Nor was this the last instance by which his late majesty distinguished his royal astronomer; for, upon his refusing to accept the living of Greenwich from a conscientious scruple, “that the duty of a pastor was incompatible with his other studies and necessary engagements,” his majesty granted him an annuity or yearly pension of 250l. during pleasure in consideration (as the sign manual, dated Feb. 15, 1752, expresses it) of his great skill and knowledge in the several branches of astronomy, and other parts of the mathematics, which have proved so useful to the trade and navigation of this kingdom. This pension was continued to the demise of the late, and renewed by the present king. The same year he was chosen one of the council of the royal society.

Dr. Bradley was extremely amiable in his private character, as well as illustrious for his scientific knowledge. His temper was gentle and placid, and he was eminently characterised by his modesty. He appears to have taken, little pains to attract the notice of mankind, and it was his singular merit alone which procured him the general esteem and regard of the friends of learning and science. Among his acquaintance and friends were many of the first persons in this kingdom, both for rank and abilities; and it is said, that there was not an astronomer of any eminence in the world, with whom he had not a literary correspondence. He spoke well, and expressed his ideas with great precision and perspicuity; but in general was silent, and seldom spoke, except when he conceived it absolutely necessary. He was, however, very ready to communicate useful knowledge to others, and especially in that science which he more particularly professed, whenever he thought there was. a proper opportunity. He also encouraged those who attended his lectures to propose questions to him, by the exactness with which he answered them, and his obvious solicitude to accommodate himself to every capacity. He was censured by some, for having withheld his observations from the public use; but this charge appears not to have been well founded: and it has been alleged, on the contrary, that an improper use was made of the facility with which he made his communications; that his observations were very ungenerously transmitted abroad; and that, by such practices, foreigners have been enabled to gain reputation, and to adopt the fruits of his labour as their own. He was extremely temperate, even to abstinence; and he enjoyed a great share of health, and was active and robust, till towards the close of his life. Eminently remarkable for the equanimity of his temper, he was yet in a very great degree compassionate and liberal; and was extremely generous to such of his relations as needed his assistance. Though he was unquestionably one of the greatest astronomers of the age, - he has published very little which seems to have arisen from his natural diffidence, and from that solicitous accuracy, which made him always apprehensive that his works were imperfect. His papers which have been inserted in the Philosophical Transactions are, 1. Observations on the comet of 1703; vol. 33, p. 41. 2. The longitude of Lisbon and of the fort of New York from Wansted and London, determined by the eclipse of the first satellite of Jupiter; vol. 34, p. 85. 3. An account of a new discovered motion of the fixed stars; vol. 35, p. 637. 4. On the going of clocks with isochronal pendulums; vol. 38, p. 302. 5. Observations on the comet of 1736-7; vol. 40, p. 111. 6. On the apparent motion of the fixed stars; vol. 45, p. 1. 7. On the occultation of Venus by the moon, the 15th of April 1751; vol. 46, p. 201. 8. On the comet of 1757; vol. 50, p. 408. 9. Directions for using the common micrometer; vol. 62, p. 46. His observations made at the royal observatory during 20 years, comprized in 13 folio and two quarto volumes, unfortunately for the interests of science, were taken away at his death by his representatives , who, upon preparations being made by government for recovering them by process of law, (and an actual commencement of a suit for that purpose,) presented them to lord North, by whom they were transferred, in 1776, to the university of- Oxford, of which he was chancellor, on condition of their printing and publishing them. Accordingly the first volume was published in, 1798, by the late Dr. Hornsby, in a splendid form, entitled “Astronomical Observations made at the Royal Observatory at Greenwich, from the year 1750 to the year 1762,” fol. The remainder are in the possession of Dr. Hornsby’s very learned successor in the astronomical chair, Dr. Abraham Rpbertson.

, a very celebrated astronomer, descended from a noble and illustrious Danish family, was born in 1546 at Knudstorp, a small lordship near Helsingborg, in Scania. His father, Otto Brahe, having a large family, Tycho was educated under the care and at the expence of his uncle George Brahe, who, having no children, adopted him as his heir. Finding his nephew a boy of lively capacity, and though only seven years of age, strongly inclined to study, he had him instructed in the Latin tongue unknown to his father, who considered literature as inglorious, and was desirous that all his sons should follow the profession of arms. In the twelfth year of his age, Tycho was removed to the academy of Copenhagen; and his mind, which, had not yet taken any direction, was casually incited to the study of astronomy by fin eclipse of the sun, which happened on. Aug. 21? 1560. He had for some time examined the astrological diaries or almanacks, which pretended to predict future events from the inspection of the stars; but when he observed that the eclipse happened at the precise time at which it was foretold, he considered that science 'as divine, which could thus so thoroughly understand the motions of the heavenly bodies as to foretel their places and relative positions: and from that moment he devoted himself to astronomy.

In this retreat Tycho Brahe passed twenty years, and greatly improved the science of astronomy by the diligence and exactness of his observations. He maintained several scholars in his house for the purpose of instructing them in geometry and astronomy, some of whom were sent and their expences defrayed by the king; others, who voluntarily offered themselves, he received and supported at his own expence. He lived at the same time in a most sumptuous manner, kept an open house with unbounded hospitality, and was always happy to entertain and receive all persons, who flocked in crowds to pay their respects to a person of his renown. During his residence in the island of Huen, he received numerous visits from persons of the highest rank. Among these must be particularly mentioned Ulric duke of Mecklenburgh, in company with his daughter Sophia, queen of Denmark; William, landgrave of Hesse Cassel, whose correspondence with Brahe on astronomical subjects has been given to the public, and who had shewn himself a constant patron to the Danish astronomer. In 1590 Tycho was honoured with a visit from James the First, then king of Scotland, when that monarch repaired to the court of Copenhagen, to conclude his marriage with the princess Anne, and was so delighted with Brahe’s apparatus and conversation, that he remained eight days at Uranienburgh. On retiring he presented Tycho with a magnificent present, and afterwards accompanied his royal licence for the publication of Tycho Brahe’s works with the following flattering testimony of his abilities and learning: “Nor am I acquainted with these things from the relation of others, or from a mere perusal of your works; but I have seen them with my own eyes, and heard them with my own ears, in your residence at Uranienburgh, during the various learned and agreeable conversations which I there held with you, which even now affect my mind to such a degree, that it is difficult to decide, whether I recollect them with greater pleasure or admiration; which I now willingly testify by this licence to present and future generations, &c.” His majesty also, at his particular request, composed, in honour of the Danish astronomer, some Latin verses, more expressive indeed of his esteem and admiration than remarkable for classic elegance.

If we were to estimate the merits of Tycho Brahe as an astronomer, we should compare the science as he left it with the state in which he found it. His great merit consisted in his inventions and improvements of mathematical instruments, and in the diligence and exactness with which he made astronomical observations for a long series of years. And as his instruments were remarkably good, he composed a catalogue of 777 fixed stars, all observed by himself, with an accuracy unknown to former astronomers. He likewise discovered the refraction of the air; demonstrated, against the prevailing opinion of those times, that the comets were higher than the moon; and from his observations on the moon and the other planets, the theories of their motions were afterwards corrected and improved. He was also the first astronomer who composed a table of refractions, and shewed the use to be made of them in astronomy. Such is the reputation of Tycho Brahe, for his great proficiency in that science, that Costard, in his History of Astronomy, has fixed upon his name as marking the beginning of a new period.

At this time he also collected materials, and made the necessary observations (being a very good mathematician and astronomer) for a new map of Jamaica, which he published in London, in August 1755, engraved by Dr. Bayly, on two sheets, by which the doctor cleared four hundred guineas. Soon after this (March 1756) he published his “Civil and Natural History of Jamaica,” in folio, ornamented with forty-nine engravings of natural history, a whole sheet map of the island, and another of the harbour of Port-Royal, Kingston-town, &c. Of this work there were but two hundred and fifty copies printed by subscription, at the very low price of one guinea, but a few were sold at two pounds two shillings in sheets by the printer. Most unfortunately all the copper-plates, as well as the original drawings, were consumed by the great fire in Cornhill, November 7, 1765. This alone prevented in his life-time a second edition of that work, for which he made considerable preparations, by many additional plants, and a few corrections in his several voyages to these islands, for he was six different times in the West Indies; in one of those trips he lived above twelve months in the island of Antigua: however, these observations will we trust not be lost to the public, as he sent before his death to sir Joseph Banks, P. R. S. “A catalogue of the plants growing in the Sugar Islands, &c. classed and described according to the Linnaean system,” in 4to, containing about eighty pages. In Exshaw’s Gentleman’s and London Magazine for June 1774, he published “A catalogue of the birds of Ireland,” and in Exshaw’s August Magazine following, “A catalogue of its fish.” In 1788 he prepared for the press a very curious and useful catalogue of the plants of the north-west counties of Ireland, classed with great care and accuracy according to the Linnsean system, containing above seven hundred plants, mostly observed by himself, having trusted very few to the descriptions of others. This little tract, written in Latin with the English and Irish names, might be of considerable use in assisting to compile a “Flora Hibernica,” a work every botanist will allow to be much wanting.

On the death of Fergusson, the celebrated lecturer on natural philosophy, which took place about the year 1775, he bequeathed to the doctor the whole of his apparatus. Unwilling that this collection, which at that period was perhaps the best this country could boast of, should remain shut up and useless, the doctor, with the assistance of his son, who conducted the experimental part, delivered several courses of lectures, during three years, at Edinburgh, with great success, the theatre being always crowded with auditors. On removing to London, he disposed of this apparatus to Dr. Lettsom. Of natural philosophy, the part which particularly attracted the doctor’s attention was astronomy. Nothing delighted him more than to point out the celestial phenomena on a fine starlight evening to any young person who appeared willing to receive information; and the friendship of the late highly respectable astronomer royal, Dr. Maskelyne, afforded him every facility of renovating his acquaintance with the planetary bodies, whenever so inclined.

, a celebrated astronomer and scholar, was born of protestant parents, at Houdun in France, September the 28th, 1605; and having finished his studies in philosophy at Paris, and in civil law at Poictiers, he applied to mathematics, theology, sacred and profane history, and civil law, with such assiduity, that he became eminent in each of these departments, and acquired the reputation of an universal genius. As he had travelled for his improvement into Italy, Germany, Poland, and the Levant, he formed an extensive acquaintance with men of letters, and maintained a correspondence with the most distinguished persons of his time. Although he had been educated a protestant, he changed his profession at the age of 27 years, and became a catholic priest. His life was prolonged to his 89th year; and having retired to the abbey of St. Victor at Paris in 1689, he died there November the 25th, 1694. Besides his pieces concerning ecclesiastical rights, which excited attention, and the history of Ducas, printed at the Louvre, in 1649, in the original Greek, with a Latin version and notes, he was the author of several other works, chiefly mathematical and philosophical. His “Treatise on the Nature of Light” was published in 1638; and his work entitled, “Philolaus, sive de vero Systema Mundi,” or his true system of the world, according to Philolaus, an ancient philosopher and astronomer, in the same year, and republished in 1645, under the title of “Astronomia Philolaica,” grounded upon the hypothesis of the earth’s motion, and the elliptical orbit described by the planet’s motion about a cone. To which he added tables entitled “Tabulæ Philolaicæ:” a work which Riccioli says ought to be attentively read by all students of astronomy. He considered the hypothesis, or approximation of bishop Ward, and found it not to agree with the planet Mars; and shewed in his defence of the Philolaic astronomy against the bishop, that from four observations made by Tycho on the planet Mars, that planet in the first and third quarters of the mean anomaly, was more forward than it ought to be according to Ward’s hypothesis; but in the 2d and 4th quadrant of the same, the planet was not so far advanced as that hypothesis required. He therefore set about a correction of the bishop’s hypothesis, and made it to answer more exactly to the orbits of the planets, which were most eccentric, and introduced what is called by Street, in his “Caroline Tables,” the Variation: for these tables were calculated from this correction of Bullialdus, and exceeded all in exactness that went before. This correction is, in the judgment of Dr. Gregory, a very happy one, if it be not set above its due place; and be accounted no more than a correction of an approximation to the true system: For by this means we are enabled to gather the coequate anomaly a priori and directly from the mean, and the observations are well enough answered at the same time; which, in Mercator’s opinion, no one had effected before. It is remarkable that the ellipsis which he has chosen for a planet’s motion, is such a one as, if cut out of a cone, will have the axis of the cone passing through one of its foci, viz. that next the aphelion.

, an eminent French Inathematician and astronomer, was born at Rumigiiy in the diocese of Rheims on March 15, 1713. His father having quitted the army, in which he had served, amused himself in his retirement with studying mathematics and mechanics, in which he proved the author of several inventions of considerable use to the public. From this example of his father, our author “almost in his infancy took a fancy to mechanics, which proved of signal service to him in his maturer years. At school he discovered early tokens of genius. He came to Paris in 1729; where he studied the classics, philosophy, and mathematics, and afterwards divinity in the college de Navarre, with a view to the church, but he never entered into priest’s orders, apprehending that his astronomical studies, to which he had become much devoted, might too much interfere with his religious duties. His turn for astronomy soon connected him with the celebrated Cassini, who procured him an apartment in the observatory; where, assisted by the counsels of this master, he soon acquired a name among the astronomers, in 1739 he was joined with M. Cassini de Thury, son to M. Cassini, in verifying the meridian through the whole extent of France; and in the same year he was, named professor of mathematics in the college of Mazarine. In 1741 or author was admitted into the academy of sciences as an adjoint member for astronomy and had many excellent papers inserted in their memoirs; beside which he published several useful treatises, viz. Elements of Geometry, Astronomy, Mechanics, and Optics. He also carefully computed all the eclipses of the sun and moon that had happened since the Christian sera, which were printed in the work entitled” L'Art de verifier les dates,“&c. Paris, 1750, 4to. He also compiled a volume of astronomical ephemerides for the years 1745 to 1755; another for the years 1755 to 1765 and a third for the years 1765 to 1775 as also the most correct solar tables of any; and an excellent work entitled” Astronomic fundamenta novissimis solis et stellarum observationibus stabilita."

, an ancient Greek poet, was born at Cyrene, a town in Africa, and flourished under the Ptolemies Philadelphus and Euergetes; Berenice, queen of the latter, having consecrated her locks in the temple of Venus, ad a flattering astronomer having translated them from thence into a constellation in the heavens, gave occasion to the fine elegy of this poet, which we have now only in the Latin of Catullus. He may be placed, therefore, about 280 B. C. His common name Battiades has made the grammarians usually assign one Battus for his father; but perhaps he may as well derive that name from king Battus, the founder of Cyrene, from whose line, as Strabo assures us, he declared himself to be descended. But whoever was his father, the poet has paid all his duties and obligations to him in a most delicate epitaph, which we find in the Anthologia; and which shews that Martial had good reason to assign him, as he has done, the crown among the Grecian writers of the epigram. He was educated under Hermocrates, the grammarian; and before he was recommended to the favour of the kings of Egypt, he taught a school at Alexandria; and had the honour of educating Apollonius, the author of the Argonautics. But Apollonius making an ungrateful return to his master for the pains he had taken with him, Callimachus was provoked to revenge himself in an invective poem, called Ibis; which, it is known? furnished Ovid with a pattern and title for a satire of the same nature. Suidas relates, that Callimachus wrote above 800 pieces; of which we have now remaining only a few hymns and epigrams, Quintilian is very justifiable in having asserted, that Callimachus was the first of all the elegiac poets. He has the credit of having first spoken the proverbial saying, “a great book is a great evil,” which critics have been fonder of repeating than authors.

, an eminent astronomer, was born of noble parents, at a town in Piedmont in Italy, June 8, 1635. After he had laid a proper foundation in his studies at home, he was sent to continue them in a college of Jesuits at Genoa. He had an uncommon turn for Latin poetry, which he exercised so very early, that poems of his were published when he was but eleven years old. At length he fell in with books of astronomy, which he read with great eagerness; and feeling a strong propensity to proceed farther in that science, in a short time he made so amazing a progress, that, in 1650, the senate of Bologna invited him to be their public methematical professor. He was not more than fifteen years of age when he went to Bologna, where he taught mathematics, and made observations upon the heavens with great care and assiduity. In 1652 a comet appeared, which he observed with great accuracy; and discovered, that comets were not bodies accidentally generated in the atmosphere, as had usually been supposed, but of the same nature, and probably governed by the same laws, as the planets. The same year he solved an astronomical problem, which Kepler and Bullialdus had given up as insolvable; viz. to determine geometrically the apogee and eccentricity of a planet from its true and mean place. In 1653, when a church of Bologna was repaired and enlarged, he obtained leave of the senate to correct and settle a meridian line, which had been drawn by an astronomer in 1575. These were circumstances very remarkable in one who had not yet attained his twentieth year. In 1657 he attended, as an assistant, a nobleman, who was sent to Rome to compose some differences which had arisen between Bologna and Ferrara, from the inundations of the Po; and shewed so much skill and judgment in the management of that affair, that in 1663, Marius Chigi, brother of pope Alexander VII. appointed him inspector-general of the fortifications of the castle of Urbino; and he had afterwards committed to him the care of all the rivers in the ecclesiastical state.

Meanwhile he did not neglect his astronomical studies, but cultivated them with great care. He made many discoveries relative to the planets Mars and Venus, especially the revolution of Mars upon his own axis; but his principal object was to settle an accurate theory of Jupiter’s satellites, which after much labour and watching he happily effected, and published it at Rome, among other astronomical pieces, in 1666. Picard, the French astronomer, getting Cassini’s tables of Jupiter’s satellites, found them so very exact, that he conceived the highest opinion of his skill; and from that time his fame increased so fast in France, that Lewis XIV. desired to have him a member of the academy. Cassini, however, could not leave his station, without leave of his superiors; and therefore Lewis requested of pope Clement IX. and of the senate of Bologna, that Cassini might be permitted to come into France. Leave was granted for six years; and he came to Paris in the beginning of 1669, where he was immediately made the king’s astronomer. When this term was near expiring, the pope and the senate of Bologna insisted upon his return, on pain of forfeiting his revenues and emoluments, which had hitherto been remitted to him; but the minister Colbert prevailed on him to stay, and he was naturalized in the latter end of 1673, in which same year also he married.

, a celebrated French astronomer, and member of the several academies of sciences of France, England, Prussia, and Bologna, was born at Paris Feb. 18, 1677, being the younger son of the preceding, whom he succeeded as astronomer at the royal observatory, the elder son having lost his life at the battle of La Hogue.

After some education in his father’s house he was sent to study philosophy at the Mazarine college, where the celebrated Varignon was then professor of mathematics; from whose assistance young Cassini profited so well, that at fifteen years of age he supported a mathematical thesis with great honour. At the age of seventeen he was admitted a member of the academy of sciences; and the same year he accompanied his father in his journey to Italy, where he assisted him in the verification of the meridian at Bologna, and other measurement* On his return he made other similar operations in a journey into Holland, where he discovered some errors in the measure of the earth by Snell, the result of which was communicated to the academy in 1702. He made also a visit to England in 1696, where he was made r a member of the royal society. In 1712 he succeeded his father as astronomer royal at the observatory. In 17 17 he gave to the academy his researches on the distance of the fixed stars, in which he shewed that the whole annual orbit, of near 200 million of miles diameter, is but as a point in comparison of that distance. The same year he communicated also his discoveries concerning the inclination of the orbits of the satellites in general, and especially of those of Saturn’s satellites and ring. In 1723 he undertook to determine the cause of the moon’s libration, by which she shews sometimes a little towards one side, and sometimes a little on the other, of that half which is commonly behind or hid from our view.

, a celebrated French astronomer, director of the observatory, pensioner astronomer, and member of most of the learned societies of Europe, was born at Paris, June 17, 1714, being the second son of the preceding, whose occupations and talents our author inherited and supported with great honour. He received his first lessons in astronomy and mathematics from Messieurs Maraldi and Camus. He was hardly ten years of age when he calculated the phases of the total eclipse of the sun of 1727. At the age of eighteen he accompanied his father in his two journeys undertaken for drawing the perpendicular to the observatory meridian from Strasbourg to Brest. From that time a general chart of France was devised; for which purpose it was necessary to traverse the country by several lines parallel and perpendicular to the meridian of Paris, and our author was charged with the conduct of this business. He did not content himself with the measure of a degree by Picard; suspecting even that the measures which had been taken by his father and grandfather were not exempt from some errors, which the imperfections of their instruments at least would be liable to, he again undertook to measure the meridian of Paris, by means of a new series of triangles, of a smaller number, and more advantageously disposed. This great work was published in 1740, with a chart shewing the new meridian of Paris, by two different series of triangles, passing along the sea-coasts to Bayonne, traversing the frontiers of Spain to the Mediterranean and Antibes, and thence along the eastern limits of France to Dunkirk, with parallel and perpendicular lines described at the distance of 6000 toises from one another, from side to side of the country. Jn 1735 he had been received into the academy as adjoint supernumerary, at twenty-one years of age.

, an eminent French astronomer, was born at Mauriac, a town in Upper Auvergne, on the 23d of May, 1728, of John Chappe, lord of the barony of Auteroche, and Magdalen de la Farge, daughter of Peter de la Farge, lord of larPierre. From his birth he enjoyed the valuable advantage of not being under the necessity of struggling, like many men of genius, with adversity and penury. The distinguished rank which his parents held in their province, added to their wealth and opulence, enabled them to bestow upon their son an excellent education, the foundation of which was laid at Mauriac, where he began his studies. Having made considerable progress here, he went afterwards to finish them at the college de Louis le Grand. M. Chappe, from his earliest infancy, shewed a surprising turn for drawing and the mathematics. Descartes was scarcely eight years of age when he was styled a philosopher, and Chappe at that age might have been called a mathematician. An irresistible impulse, and singular disposition, as if innate, led him to draw plans and make calculations; but these pursuits, quite forojgn to the studies in which he was then engaged, occupied no part of that time which was allotted for them. He applied to the former only at those moments which the regulations. of the college suffered him to call his own.

The abbe Chappe, however, made himself known in the astronomical world by a work of much greater importance. This was a translation of the works of Dr. Halley from the English. This translation appeared in 1752; and the additions made by the translator, and the new inferences he drew from the labours of the English astronomer, placed him almost on a level with the author. The abbe Chappe had now given too striking a specimen of his talents not to attract the notice of government. The king having ordered plans of several places in the district at Bitche in Lorraine to be taken, and the forest in the neighbourhood of the town of that name to be surveyed, the abbe Chappe’s merit procured him the superintendance and direction of this business; and the event shewed, that the ministry could not have chosen a person more deserving of their confidence. On his return from this expedition he was elected a member of the royal academy of sciences; and on the 17th of January 1759, he obtained the place of assistant astronomer, vacant by the promotion of M. de la Lande to that of associate.

, a peer of France, but more remarkable as an astronomer and mathematician, was born at Paris Dec. 30, 1714. He soon discovered a singular taste and genius for the sciences; and in the tumults of armies and camps, he cultivated mathematics, astronomy, mechanics, &c. He was named honorary academician the 27th of February 1743, and few members were more punctual in attending the meetings of that body, where he often brought different constructions and corrections of instruments of astronomy, of dioptrics, and achromatic telescopes. These researches were followed with a new parallactic machine, more solid and convenient than those that were in use; as also with many reflections on the manner of applying the micrometer to those telescopes, and of measuring exactly the value of the parts of that instrument. The duke of Chaulnes proposed many other works of the same kind, which were interrupted by his death Sept. 23, 1769.

, in Latin Claramontius, an eminent Italian astronomer and philosopher, was born at Cesena in the province of Romagna in June 1565. His father was a physician at Cesena. He studied at Perugia and Ferrara, and became distinguished for his progress in philosophy and mathematics;, the former of which he taught for some time at Pisa. He passed, however, the greater part of his long life at Cesena, and in his history of that place, which he published in 1641, he informs us, that for fifty -nine years he had served his country in a public capacity. He was, in particular, frequently deputed to Rome, either to offer obedience to the pope in the name of his countrymen, or on other affairs. He had married a Jady whom he calls Virginia de Abbatibus, but becoming a widower at the age of eighty, he went into the church, received priest’s orders, and retired with the priests of the congregation of the oratory, for whom he built a church at Cesena, and there he died Oct. 3, 1652, in his eightyseventh year. He established at Cesena the academy of the Oifuscati, over which he presided until his death. His works, written partly in Italian and partly in Latin, are very numerous, and filled a considerable space in the literary history of his time: 1. “Discorso della Cometa pogonare dell' anno 1618, &c.” Venice, 1619, 4to, in which he suggests that comets are sublunary, and not celestial bodies. 2. “Anti-Tycho, in quo contra Tychonem Brahe, et nonnullos alios, &.c. demonstrator Cometas esse sublunares,” Venice, 1621, 4to. Kepler on this occasion stept forward in defence of Tycho Brahe, who had been dead some years. 3. “De conjectandis cuj usque moribus et latitantibus animi affectibus semeiotice moralis, seu de signis libri decem,” ibid. 1625, 4to, reprinted by Herman Conringius, who calls it an incomparable work, at Helmstadt, in 1665, 4to. MorhofT also praises it highly. M. Trichet Dufresne brought a copy of it for the first time into France, and M. de la Chambre availed himself of it in his work on the passions. 4. “Notse in moralem suam semeioticam, seu de signis,” Cesena, 1625, 4to. It is, perhaps, unnecessary to inform our readers that physiognomy was a favourite study from the beginning of the fifteenth to the end of the sixteenth century, and Chiaramonti appears to have made as much progress in it as any of his contemporaries. 5. An answer to Kepler, under the title “Apologia pro Anti-Tychone suo adversus Hypcraspiten Joannis Kepleri,” Venice, 1626, 4to. 6. “De tribus novis stellis, quse annis 1572, 1600, et 1604, comparuere,” Cesena, 1628, 4to. Galileo now took the part of Tycho Brahe, and published in Italian a work against Chiaramonti, who answered it in, 7. “Difesa di Scipioni Chiaramonti, &c.” Florence, 1633, 4to. 8. “Delia ‘ragione di stato libri tre, nel quale trattato da primi priticipii dedotto si suo prona la natura, le massime, e le specie cle’ governi buoni, cattivi e mascherati,” Florence, 1635, 4to, and translated into Latin, Hamburgh, 1679, 4to. 9. “Examen ad censuram Joannis Camilli Gloriosi in hbrum de tribus novis stellis,” ibid. 1636, 4to. 10. “De sede sublunari Cometarum, opuscula tria,” Amst. 1636, 4to. If. “Castigatio J. Camilli Gloriosi adversus Claramontium castigata ab ipso Claramontio,” Cesena, 1638, 4to. 12. “De methodo ad doctrinam spectante, libri quatuor, &c.” ibid. 1639, 4to. 13. “Csesense Historia libris sexdecim, ab initio civitatis ad haec tempera,” with a sketch of the general history of Italy during the same period, Cesena, 1641, 4to. 14. “De atrabile, quoad mores attinet,” Paris, 1641, 8vo, dedicated to Naude, but in the licence it is erroneously said that the author was physician to the pope. 15. “Anti-Philolaus, in quo Philolaus redivivus de terrse motu et solis ac fixarum quiete impugnalur,” &c. Cesena, 1643, 4to. This was written against Bullialdus’s attempt to revive the system of Philolaus, but in this we doubt whether our author was equal to his antagonist. 16. “Defensio ab oppugnationibus Fortunii Liceti de sede Cometarum,” Cesena, 1644, 4to. 17. “De Universo, libri sexdecim,” Cologne, 1644, 4to. 18. One of his best works, “De altitudine Caucasi liber unus, cura Gab. Naudasi editus,” Paris, 1649, 4to, and 1680, 4to. 19. “Philosophia naturalis methodo resolutiva tradita, &c.” Cesena, 1652, 4to. 20. “Opuscula varia mathematica,” Bologna, 1653, 4to. 21. “Commentaria in Aristotelem de iri.de, &c.” ibid. 1654, 4to. 22. “In quatuor meteorum Aristotelis librum commentaria,” Venice, 1668, 4to. 23. “Delle, scene, e theatri opera posthuma,” Cesena, 1675, 4to.

The severe illness with which lord Clive was attacked, during his first residence in the East Indies, gave an injury to his constitution which was never fully repaired; and his health was farther weakened by his successive visits to the unwholesome climates of that country. Hence it was that he became subject at times to a depression of spirits. His ardent and active mind, when not called into exertion by some great occasion, frequently preyed upon itself. In the latter part of his life, having nothing peculiarly important and interesting to engage his attention, and his body growing more and more infirm, the depression increased; and to this was owing his decease, by his own hand, on the 22d of November, 1774, not long after he had entered into the 50th year of his age. He was interred at Moreton-Say, the parish in which he was born. In the various relations of private life, lord Clive was highly beloved and esteemed; for he was a man of the kindest affections, and of every social virtue. His secret charities- were numerous and extensive but the present he made of seventy thousand pounds, as a provision for the invalids of the company’s service, was the noblest donation of its kind that ever came fron a private individual. His person was of the largest of the middle size; his countenance inclined to sadness; and the heaviness of his brow imparted an unpleasing expression to his features. It was a heaviness that arose not from the prevalence of the unsocial passions (for of these lew men had a smaller share), but from a natural fullness in the flesh above the eye-lid. His words were few; and his manner, among strangers, was reserved; yet it won the confidence of men, and gained admission to the heart. Among his intimate friends he had great pleasantness and jocularity, and on some occasions was too open. In February 1753, immediately before he embarked for England, Jie married Margaret, daughter of Edmund Maskelyne, esq. of Purton in Wiltshire, and sister to the rev. Dr. Nevil Maskelyne, the late astronomer royal. By this lady he had Edward, the present lord Clive, born March 7, 1754; Rebecca, born September 15, 1760; Charlotte, born January 15, 1762; Margaret, born August 15, 1763; and Robert, 'horn August 31, 1769.

, an eminent astronomer, was born at Thorn in Prussia, January 19, 1473. His father was a stranger, but from what part of Europe is unknown. He settled here as a merchant, and the archives of the city prove that he obtained the freedom of Thorn in 1462. It seems clear that he must have been in opulent circumstances, and of consideration, not only from the liberal education which he bestowed upon his son, but from the rank of his wife, the sister of Luca Watzelrode, bishop of Ermeland, a prelate descended from one of the most illustrious families of Polish Prussia. Nicholas was instructed in the Latin and Greek languages at home; and afterward sent to Cracow, where he studied philosophy, mathematics, and medicine: though his genius was naturally turned to mathematics, which he chiefly studied, and pursued through all its various branches. He set out for Italy at twenty-three years of age; stopping at Bologna, that he might converse with the celebrated astronomer of that place, Dominic Maria, whom he assisted for some time in making his observations. From hence he passed to Rome, where he was presently considered as not inferior to the famous Regiomontanus. Here he soon acquired so great a reputation, that he was chosen professor of mathematics, which he taught there for a long time with the greatest applause and here also he made some astronomical observations about the year 1500.

, a celebrated mathematician, philosopher, and astronomer, was born July 10, 1682, at Burbach in Leicestershire, where his father Robert was rector. He was first placed at Leicester school; where, at only twelve years of age, he discovered a strong inclination to the mathematics. This being observed by his uncle, the rev. Mr. John Smith, he gave him all imaginable encouragement; and prevailed with his father to send him for some time to his house in Lincolnshire, that he might assist him in those studies. Here he laid the foundation of that deep and extensive knowledge, for which he was afterwards so deservedly famous. He removed from thence to London, and was sent to St. Paul’s school; where also he made a great progress in classical learning; yet found so much leisure as to keep a constant correspondence with his uncle, not only in mathematics, but also in metaphysics, philosophy, and divinity. This fact is said to have been often mentioned by professor Saunderson. His next remove was to Cambridge; where, April 6, 1699, he was admitted of Trinity college; and at Michaelmas 1705, after taking his first degree in arts, chosen fellow of it. He was at the same time tutor to Anthony earl of Harold, and the lord Henry de Grey, sons of the then marquis (afterwards duke of) Kent, to which noble family Mr. Cotes was related.

, a lady of great genius and learning, was born in Silesia about the beginning of the seventeenth century, and became celebrated for her extensive knowledge in many branches of learning, particularly in mathematics and astronomy, upon which she wrote several ingenious treatises; one of which, under the title of “Urania Propitia,” printed in 1650, in Latin and German, she dedicated to Ferdinand III. emperor of Germany. In this work are contained astronomical tables, of great ease and accuracy, founded upon Kepler’s hypothesis. She learned languages with amazing facility; and understood Polish, German, French, Italian, Latin, Greek, and Hebrew. With equal ease she acquired a knowledge of the sciences: history, physic, poetry, painting, music both vocal and instrumental, were familiar to her; and yet these were no more than her amusement. Her favourite study was the mathematics, and especially astronomy, to which she principally applied, and was not without reason ranked among the most able astronomers of her time. She married Elias de Levvin, M. D. also an astronomer; and they carried on their favourite studies for some time with equal reputation and success, until the war penetrated into Silesia, and obliged them to quit their residence at Schweinitz, for Poland, which was then at peace. Upon their journey, although furnished with the best passports, they were robbed by the soldiers; but, on their arrival in Poland, were welcomed with every kind attention. Here she composed her astronomical tables above noticed, first printed at Oels, and four years after at Franeker or Francfort. Moreri fixes her death at 1664, but others think she was living in 1669, and then a widow.

D'Arquier (Augustine), a French astronomer, fellow of the royal society of Toulouse, correspondent member of the royal academy of Paris, and a member of the Institute, was born at Toulouse, Nov. 23, 1718, and having early cultivated the science of astronomy, and the sciences connected with it, devoted his long life to the same pursuits, and acquired great reputation among his countrymen. Such was his enthusiasm, that, without any assistance from government, he purchased the most valuable instruments, erected an observatory on his house, taught scholars, and defrayed the expence of calculations, &c. He died in his native city, Jan. 18, 1802. He published, 1. “Observations Astronomiques faites a Toulouse, &c.” Paris, 1778, 4to, the most complete collection of observations that had ever been furnished from a provincial city. There are six hundred of the moon, thirtythree oppositions, several observations of Mercury, of the spots in the sun, the satellites of Jupiter, and the eclipses of the stars. One of the most surprizing circumstances in this collection is the great number of the passages of Mercury that have been observed by M. D'Arquier, notwithstanding the pretended difficulties which have discouraged modern astronomers from observing that planet. 2. “Observations Astronomiques,” 1783, 2 vols. 4to, containing a series of the usual astronomical observations, from 1748 to 1781: some useful instructions on the management of the pendulum: and observations on the motion and magnitude of the Georgium sidus. 3. “Lettres sur l'astronome pratique,” 1786, 8vo. Besides these he published some translations, as Simson’s Geometry, Lambert’s Cosmological Letters, and Ulloa’s Observation on the eclipse of the sun in 1778. D'Arquier died Jan. 18, 1802, in Toulouse.

, an excellent mathematician, mechanic, and astronomer, was born at Chamberry, the capital of Savoy, in 1611; and descended from a noble family, which had produced several persons creditably distinguished in the church, the law, and the army. He was a great master in all the parts of the mathematics, and printed several books on that subject, which were very well received. His principal performances are, an edition of Euclid’s Elements, where he has struck out the unserviceable propositions, and annexed the use to those he has preserved; a discourse of fortification; and another of navigation. These performances, with some others, were first collected into three volumes in folio, under the title of “Mundus Mathematicus,” comprising a very ample course of mathematics. The first volume includes the first six books of Euclid, with the eleventh and twelfth; an arithmetical tract; Theodosius’s spherics; trigonometry; practical geometry; mechanics; statics; universal geography; a discourse upon the loadstone; civil architecture, and the carpenter’s art. The second volume furnishes directions for stone-cutting; military architecture; hydrostatics; a discourse of fountains and rivers hydraulic machines, or contrivances for waterworks; navigation; optics; perspective; catoptrics, and dioptrics. The third volume has ki it a discourse of music pyrotechnia, or the operations of fire and furnace a discourse of the use of the astrolabe gnomonics, or the art of dialling; astronomy; a tract upon the calendar; astrology; algebra; the method of indivisible and conic sections. The best edition of this work is that of Lyons, printed in 1690; which is more correct than the first, is considerably enlarged, and makes four vols. in folio. Dechales, though not abounding in discoveries of his own, is yet allowed to have made a very good use of those of other men, and to have drawn the several parts of the science of mathematics together with great clearness and judgment. It is said also, that his probity was not inferior to his learning, and that both these qualities made him generally admired and beloved at Paris; where for four years together he read public mathematical lectures in the college of Clermont He then removed to Marseilles, where he taught the art of navigation; and aiterwards became professor of mathematics in the university of Turin, where he died March 28, 1678, aged 67.

, an ingenious electrician, was born in the parish of St. Martin’s, London, in 1710. His father having escaped from France to Holland, upon the revocation of the edict of Nantes, came over to England with king William. He died soon after the birth of his son, who was brought up by his uncle, an officer in the English service, and page of honour to queen Mary, who placed him at Westminster school. Whilst pursuing his studies there, he boarded in the house of Dr. Desaguliers, who instructed him in the mathematics and natural philosophy. At the age of seventeen, before he had left school, he married; and went to Leyden and followed his studies in the university of that place. In 1740, he began to read lectures in experimental philosophy at Edinburgh, and continued them till he was interrupted by the rebellion. He then took up arms for government, and was a volunteer at the battle of Preston-pans. In 1746, he resumed his lectures, and published his discovery of the effects of electricity upon the growth of vegetables. This discovery was afterwards claimed by abbé Nollet; but is very properly assigned to Dr. Demainbray by Dr. Priestley, in his “History of Electricity.” In 1749, Dr; Demainbray went to Dublin, where he read his lectures with much success, as he did afterwards in several of the French universities, who honoured him with prize medals, and admitted him into their societies. In 1753, being then at Paris, he was invited over to England, to read a course of lectures to his present majesty (then prince of Wales) and the duke of York. On his return to England he married a second wife, his first wife having died about the year 1750. In 1755 he read a public course of lectures in the concert-room in Panton-street, and in 1757 in Carey-street, opposite Boswell-court. After this he gave private courses to other branches of the royal family; and on the arrival of her present majesty in England, instructed her in experimental philosophy, and natural history. In 1768, he was appointed astronomer to his majesty’s new observatory at Richmond, and adjusted the instruments there in time to observe the transit of Venus, which happened the ensuing year. Dr. Demainbray died at Richmond Feb. 20, 1782, and was interred in the churchyard of Northall, where he had purchased a small estate.

Mr. Dollond’s celebrity in optics became now universal; and the friendship and protection of the most eminent men of science, flattered and encouraged his pursuits. To enumerate the persons, both at home and abroad, who distinguished him by their correspondence, or cultivated his acquaintance, however honourable to his memory, would be only an empty praise. Yet among those who held the highest place in his esteem as men of worth and learning, may be mentioned, Mr. Thomas Simpson, master of the royal academy at Woolwich; Mr. Harris, assaymaster at the Tower, who was at that time engaged in writing and publishing his “Treatise on Optics;” the rev. Dr. Bradley, then astronomer royal; the rev. William Ludlam, of St. John’s college, Cambridge and Mr. John Canton, a most ingenious man, and celebrated not less for his knowledge in natural philosophy, than for his neat and accurate manner of making philosophical experiments. To this catalogue of the philosophical names of those days, we may add that of the late venerable astronomer-royal, the rev. Dr. Maskelyne, whose labours have so eminently benefited the science of astronomy.

, a writer of the ninth century, better known by his works than his personal history, is supposed to have been a native of Ireland, who emigrated to France, and there probably died. Cave and Dupin call him deacon, but Dungal himself assumes no other title than that of subject to the French kings, and their orator. In his youth he studied sacred and profane literature with success, and taught the former, and had many scholars, but at last determined to retire from the world. The influence which Valclon or Valton, the abbot of St. Denis near Paris, had over him, with some other circumstances, afford reason to think that if he was not a monk of that abbey, he had retired somewhere in its neighbourhood, or perhaps resided in the house itself. During this seclusion he did not forsake his studies, but cultivated the knowledge of philosophy, and particularly of astronomy, which was much the taste of that age. The fame he acquired as an astronomer induced Charlemagne to consult him in the year 811, on the subject of two eclipses of the sun, which took place the year before, and Dungal answered his queries in a long letter which is printed in D'Acheri’s Spicilegium, vol. III. of the folio, and vol. X. of the 4to edition, with the opinion of Ismael Bouillaud upon it. Sixteen years after, in the year 827, Dungal took up his pen in defence of images against Claude, bishop of Turin, and composed a treatise which had merit enough to be printed, first separately, in 1608, 8vo, and was afterwards inserted in the “Bibliotheca Patrum.” It would appear also that he wrote some poetical pieces, one of which is in a collection published in 1729 by Martene and Durand. The time of his death is unknown, but it is supposed he was living in the year 834.

, a Pythagorean philosopher, of Cnidus, a city of Caria in Asia Minor, flourished about 370 years before Christ. He learned geometry from Archytas, and afterwards travelled into Egypt to learn astronomy and other sciences. There he and Plato studied together, as Laertius informs us, for the space of thirteen years; and afterwards came to Athens, fraught with all sorts of knowledge, which they had imbibed from the priests. Here Eudoxus opened a school, which he supported with so much glory and renown, that even Plato, though his friend, is said to have envied him; he also composed elements of geometry, from whence Euclid liberally borrowed, as mentioned by Proclus. Cicero calls Eudoxus the greatest astronomer that had ever lived: and Petronius says, he spent the latter part of his life upon the top of a very high mountain, that he might contemplate the stars and the heavens with more convenience and less interruption: and we learn from Strabo, that there were some remains of hisi observatory at Cnidus, to be seen even in his time. None of his works are extant, but he is said by Fabricius (Bibl. GriEC. lib. hi. c. 5.) to have written upon music, and he gathers from Theon of Smyrna, p. 94, that Eudoxus was the first who expressed the ratios of concords by numbers, and who discovered that grave and acute sounds depend on the slow or quick vibrations of the sounding body. He died in the fifty-third year of his age.

, a man of considerable learning, but unfortunately connected with the French prophets, was a native of Switzerland, whither his family, originally Italians, were obliged to take refuge, for religion’s sake, in the beginning of the reformation. He was born Feb. 16, 1664. His father intending him for the study of divinity, he was regularly instructed in Greek and Latin, philosophy, mathematics, and astronomy; learned a little of the Hebrew tongue, and began to attend the lectures of the divinity professors of Geneva: but his mother being averse to this, he was left to pursue his own course, and appears to have produced the first fruits of his studies in some letters on subjects of astronomy sent to Cassini, the French king’s astronomer. In 1682 he went to Paris, where Cassini received him very kindly. In the following year he returned to Geneva, where he became particularly acquainted with a count Fenil, who formed the design of seizing, if not assassinating the prince of Orange, afterwards William III. This design Faccio having learned from him communicated it to bishop Burnet about 1686, who of course imparted it to the prince. Bishop Burnet, in the first letter of his Travels, dated September 1685, speaks of him as an incomparable mathematician and philosopher, who, though only twenty-one years old, was already become one of the greatest men of his age, and seemed born to carry learning some sizes beyond what it had hitherto attained. Whilst Dr. Calamy studied at the university of Utrecht, Faccio resided in that city as tutor to two young gentlemen, Mr. Ellys and Mr. Thornton, and conversed freely with the English. At this time he was generally esteemed to be a Spinozist; and his discourse, says Dr. Calamy, very much looked that way. Afterwards, it is probable, that he was professor of mathematics at Geneva. In 1687 he came into England, and was honoured with the friendship of the most eminent mathematicians of that age. Sir Isaac Newton, in particular, was intimately acquainted with him. Dr. Johnstone of Kidderminster had in his possession a manuscript, written by Faccio, containing commentaries and illustrations of different parts of sir Isaac’s Principia. About 1704 he taught mathematics in Spitafnelds, and obtained about that time a patent fora species of jewel-watches. When he unfortunately attached himself to the new prophets, he became their chief secretary, and committed their warnings to writing, many of which were published. The connexion of such a man with these enthusiasts, and their being supported, likewise, by another person of reputed abilities, Maximilian Misson, a French refugee, occasioned a suspicion, though without reason, that there was some deep contrivance and design in the affair. On the second of December, 1707, Faccio stood in the pillory at Charing-cross, with the following words affixed to his hat: “Nicolas Fatio, convicted for abetting and favouring Elias Marion, in his wicked and counterfeit prophecies, and causing them to be printed and published, to terrify the queen’s people.” Nearly at the same time, alike sentence was executed upon Elias Marion, one of the pretended prophets, and John d'Ande, another of their abettors. This mode of treatment did not convince Faccio of his error; and, indeed, the delusion of a man of such abilities, and simplicity of manners, was rather an object of compassion than of public infamy and punishment. Oppressed with the derision and contempt thrown upon himself and his party, he retired at last into the country, and spent the remainder of a long life in silence and obscurity. He died at Worcester in 1753, about eightynine years old. When he became the dupe of fanaticism, he seems to have given up his philosophical studies and connections. Faccio, besides being deeply versed in all branches of mathematical literature, was a great proficient in the learned and oriental languages. He had read much, also, in books of alchymy. To the last, he continued a firm believer in the reality of the inspiration of the French prophets. Dr. Wall of Worcester, who was well acquainted with him, communicated many of the above particulars to Dr. Johnstone, in whose hands were several of Faccio’s fanatical manuscripts and journals; and one of his letters giving an account of count Fenil’s conspiracy, and some particulars of the author’s family was communicated to the late Mr. Seward, and published in the second volume of his Anecdotes. In the Republic of Letters, vol. I. we find a Latin poem by Faccio, in honour of sir Isaac Newton; and in vol. XVIII. a communication on the rules of the ancient Hebrew poesy, on which subject he appears to have corresponded with Whiston. There are also many of his original papers and letters in the British Museum; and among them a Latin poem, entitled “N. Facii Duellerii Auriacus Throno-Servatus,” in which he claims to himself the merit of having saved king William from the above-mentioned conspiracy.

, an eminent experimental philosopher, mechanist, and astronomer, was born in Bamffshire, in Scotland, 1710, of very poor parents. At the very earliest age his extraordinary genius began to unfold itself. He first learned to read, by overhearing his father teach his elder brother: and he had made this acquisition before any one suspected it. He soon discovered a peculiar taste for mechanics, which first arose on seeing his father use a lever. He pursued this study a considerable length, while he was yet very young; and made a watch in wood-work, from having once seen one. As he ha'd at first no instructor, nor any help from books, every thing he learned had all the merit of an original discovery; and such, with inexpressible joy, he believed it to be.

, an eminent German astronomer, was born May 28, 1721, at Achleiten, a village in hither Austria, not far from Kremsmunster. He received the rudiments of his education in the convent of Kremsmunster, which was indebted to his uncle the abbot, Alexander Fixlmillner, for an excellent school and an observatory. Placidus conceived an early attachment to the mathematics, and took so much pleasure in delineating mathematical figures, that his mother, out of derision, called him the almanack-maker. After some stay at the above seminary he removed to Salzburg, where he completed his course of philosophy, and obtained in that faculty the degree of doctor. His taste for the mathematics, however, became still stronger. His father having asked him one da)' what present he should give him, he requested Wolff’s Epitome of the Mathematics; which he studied with the greatest pleasure and satisfaction during such hours as he could spare from his other avocations: but having destined himself for the convent, he was admitted a noviciate at Kremsmunster, in 1737, and next year he publicly took the vows before the abbot Alexander. After a stay of two years in the convent, he was sent again to Salzburg, to complete his studies in jurisprudence and theology; but at the same time he applied with great assiduity to the mathematics, languages, history, and antiquities. He learned also to play on the harpsichord and organ, and made so much progress in music, that he composed several pieces, both in the sacred and theatrical style. He disputed in some theological theses; and in 1745 returned to his convent, where he was consecrated to the priesthood.

Alexander’s successor, the abbot Berthold Voge), who long resided at Salzburg, as professor of canon law and rector of the university, being well acquainted with Fixlmillner’s great knowledge, particularly in the mathematics, appointed him in 1762 to be astronomer at Kremsmunster, with leave to retain his office as professor of canon-law. He now applied with great zeal to render himself more fit for his new occupation, as he had not yet attended much to practical astronomy, and was even but little acquainted with those books from which he could obtain information on the subject. His great attachment, however, to this science, fine genius, and a desire of being useful to the institution in which he resided, and to the world, made him overcome every difficulty. The first book that fell into his hands was Lalande’s “Exposition du Calctil Astronomique,” with which alone, without any ^oral instruction, he began to study and to make observations. This work, together with Ylacq’s Logarithmic Tables, were for a long time his only sources and guides, till he at length obtained Lalande’s large work on astronomy. Fortunately, a carpenter, John Illinger, born in a village belonging to the abbey, though he could neither read nor write, waa able, under the direction of Fixlmillner, to construct for him very neat mural quadrants, zenith sectors, transit instruments, and pendulum clocks. Other instruments were made for him by Brander, of Augsburgh, and he procured achromatic telescopes from Dollond; so that by his activity the observatory at Kremsmunster soon became one of the most celebrated, and best supplied with apparatus, in Germany.

The important service rendered to the science of astronomy by Fixlmillner, is well known to all astronomers. The great number of his observations of Mercury at a time when they were rare and difficult to be made, enabled Lalande to complete his accurate tables of that planet, for which the French astronomer publicly returned him thanks. Fixlmillner was one of the first astronomers who observed the orbit of the newly-discovered planet Uranus. He was also the first who supported Bode’s conjecture, that the star 34 in the Bull, observed by Flamsteed in 1690, and which afterwards disappeared, was the new planet. Fixlinillner was a man of so great application and activity, that he not only made observations, but calculated them all himself, and deduced from them the necessary results. All his observations, of whatever kind, he calculated on the spot; and to avoid errors, he always calculated them a second time. To uncommon industry he united great penetration and deep reflection, as is proved by the many excellent remarks and discoveries to be found in his works. It must here be added, that this able astronomer lived in a remote part of the country, at a distance from all literary helps, and from others who pursued the same studies; from every thing, indeed, that could animate his zeal; yet he continued to the last day of his life, a singular instance of perseverance and attachment to his favourite study. But few men were so little subject to the imperious power of the passions. Simple in his manners, he possessed great equanimity and firmness, like the immutable laws of nature which he studied. His wide extended celebrity did not render him proud; whatever was written or said in his praise, he endeavoured rather to conceal than to publish. His close application at length impaired his health, and brought on obstinate obstructions, which ended in a diarrhoea. He died Aug. 27, 1791, in the seventy-first year of his age, the fifty-third of his residence in the convent; and the forty-sixth after his entering into the priesthood,

, a very eminent English astronomer, was born of reputable parents at Denby in Derbyshire, Aug. 19, 1646. He was educated at the free-school of Derby, where his father lived; and at fourteen was visited with a severe fit of sickness, which being followed by other distempers, operating upon a very delicate constitution, prevented his going to the university, as was designed. He was taken from school in 1662, and within * month or two after had Sacrobosco’s book “De Sphscra,” put into his hand, which he set himself to read without any director. This accident, and the leisure that attended it, laid the groundwork of all that mathematical and astronomical knowledge, for which he became afterwards so justly celebrated. He had already perused a great deal of history, ecclesiastical, as well as civil: but astronomy was entirely new to him, and he found great pleasure in it. Having translated as much from Sacrobosco, as he thought necessary, he proceeded to make dials by the direction of such ordinary books as he could get together; and having changed a volume of astrology, found among his father’s books, for Mr. Street’s Caroline Tables, he undertook to calculate the places of the planets, but found very little help from that concise author.

Having taken his degree of master of arts at Cambridge, he designed to enter into orders, and to settle on a small living near Derby, promised to him by a friend of his father’s. In the mean time, sir Joitas Moore, having notice of his design, wrote to him to come to London, whither he returned Feb. 1674-5. He was entertained in the house of that gentleman, who had other views for serving him, but Flamsteed persisting in his resolution to take orders, he did not dissuade him from it. March following, sir Jonas brought him a warrant to be the king’s astronomer, with a salary of iOOl. per annum, payable out of the office of ordnance, to commence from Michaelmas before; which, however, did not abate his inclinations for orders, so that at Easter following he was ordained at Elyhouse by bishop Gunning, who ever after conversed freely with him, and particularly upon the new philosophy and opinions, though that prelate always maintained the old. August 10, 1675, the foundation of the royal observatory at Greenwich was laid; and during the building of it, Flamsteed lodged at Greenwich; and his quadrant and telescopes being kept in the queen’s house there, he observed the appulses of the moon and planets to the fixed stars. In 1681, his “Doctrine of the Sphere” was published in a posthumous work of sir Jonas Moore, entitled, “A new System of the Mathematics,” printed in 4to.

an eminent Italian poet and physician, was born at Verona in 1483. Two singularities are related of him in his infancy; one, that his lips adhered so closely to each other when he came into the world, that a surgeon was obliged to divide them with his knife; the other, that his mother, Camilla Mascarellia, was killed by lightning, while he, though in her arms at the very moment, escaped unhurt. Fracastorio was of parts so exquisite, and made so wonderful a progress in every thing he undertook, that he became eminently skilled, not only in the belles lettres, but in all arts and sciences. He was a poet, a philosopher, a physician, an astronomer, and a mathematician. He was a man also of great political consequence, as appears from pope Paul Ill.'s making use of his authority to remove the council of Trent to Bologna, under the pretext of a contagious distemper, which, as Fracastorio deposed, made it no longer safe for him to continue at Trent. He was intimately acquainted with cardinal Bembo, Julius Scaliger, and all the great men of his time. He died of an apoplexy, at Casi near Verona, in 1553; and in 1559 the town of Verona erected a statue in honour of him.

, the celebrated astronomer and mathematician, was the son of Vincenzo Galilei, a nobleman of Florence, not less distinguished by his quality and fortune, than conspicuous for his skill and knowledge in music; about some points in which science he maintained a dispute with the famous Zarlinas. His wife brought him this son, Feb. 10, 1564, either at Pisa, or, which is more probable, at Florence. Galileo received an education suitable to his birth, his taste, and his abilities. He went through his studies early, and his father then wished that he should apply himself to medicine;. but having obtained at college some knowledge of mathematics, his genius declared itself decisively for that study. He needed no directions where to begin. Euclid’s Elements were well known to be the best foundation in this science. He therefore set out with studying that work, of which he made himself master without assistance, and proceeded thence to such authors as were in most esteem, ancient and modern. His progress in these sciences was so extraordinary, that in 1589, he was appointed professor of mathematics in the university of Pisa, but being there continually harrasted by the scholastic professors, for opposing some maxims of their favourite Aristotle, he quitted that place at the latter end of 1592, for Padua, whither he was invited very handsomely to accept a similar professorship; soon after which, by the esteem arising from his genius and erudition, he was recommended to the friendship of Tycho Brache. He had already, even long before 1586, written his “Mechanics,” or a treatise of the benefits derived from that science and from its instruments, together with a fragment concerning percussion, the first published by Mersennus, at Paris, in 1G34-, in “Mersenni Opera,” vol. I. and both by Menoless, vol. I. as also his “Balance,” in which, after Archimedes’s problem of the crown, he shewed how to find the proportion of alloy, or mixt metals, and how to make theuaid instrument. These he had read to his pupils soon after his arrival at Padua, in 1593.

, a learned Italian astronomer, who lived in the sixteenth century, and was a member of the academy of Venice, is said to have invented an instrument for observing the celestial phenomena. He published several works, among which are, 1. “Delia fabrica et uso di diversi stromenti di Astronomia et Cosmografia,” Venice, 1597. 2. “Specimen Uranicum,” Venice, 1595. 3. “Ccelestium corporum et rerum ab ipsis pendentium Explicatio,” Venice, 1605. This work has been improperly ascribed to Paulus Galvicius in the catalogue of Thuanus’s library. 4. “Theatrum mundi et temporis,” Venice, 1589. 5. “De Themate erigendo, parte fortune, divisione Zodiaci, dignitatibus Planetarum et temporibus ad medicandum accommodatis.” This is printed with “Hasfurtus de cognosceudis et medeudis morbis ex corporum coelestium positione, cui argumenta et explicationem inscripsit,” Venice, 1584.

, an ingenious French writer, was born at Goron in the Maine, March 13, 1729. After b.eing educated, probably in his own country, he came to Paris, withput money or interest, and depending only on his learning. This soon recommended him, however, to a place in the college of Harcourt, and in 1760 he was appointed coadjutor to the abbé Sellier in the royal college, and was made before 1764 Hebrew professor, and chosen a member of the academy of inscriptions au4 belles lettres. His useful studies were interrupted by the revolution, and in 1793 he was compelled ta fly, for refusing the republican oaths. He then went to Bougival, where he died in 1795. All he could save from confiscation was his library; but his friend Lalande, the celebrated astronomer, so effectually represented to the government, the disgrace of suffering a man of so much merit to want bread, that a pension was granted him. He wrote, 1. “L'Homme de lettres,” Paris, 1764, 2 vols. 12mo, in which the method he lays down to form a map of letters is highly liberal and ingenious. 2. “Traité” de l'origine du gouveruement françoise,“1765, ib. 12 mo. 3.” De l'education civile,“1765, 12mo. 4.” De commerce remis a sa place." In 1770 he published the 9th vol. 4to of Velly and Villaret’s History of France, beginning with the year 1469, and continuing his labours in this work, produced the 15th vol. in 1786, displaying throughout the whole more erudition than his predecessors. He wrote several papers in the memoirs of the academy of inscriptions, relative, among other subjects, to the philosophy of the ancients, and especially to that of Plato, of which he was perhaps rather too fond, though less fanciful than some modern Platonists.

, a physician and astronomer, who wrote a commentary on the “Syntaxis Magna” of Ptolemy, in nine books, and several other works, is supposed to have been a Greek by nation; some call him “the Arabian,” and others say that he was born at Seville in Spain of Arabian parents. There is as much diversity of opinion as to the age in which he flourished, some contending for the seventh, some for the eighth, and some for the ninth century. His commentary above mentioned was published at Nuremburg in 1533. In it he endeavoured to correct the astronomy of Ptolemy, but Copernicus called him rather the calumniator of Ptolemy. He was a learned chemist, and as such has been mentioned with respect by the great Boerhaave; but he was also addicted to the reveries of Alchemy, and condescended to use occasionally a jargon suited to the mystic pretensions of those fanciful writers. Dr. Johnson was of opinion, that gibberish is best derived from this unintelligible cant of Geber and his followers: anciently, he alledges, it was written gebrish. Notwithstanding this, it is allowed that his writings contain much useful knowledge, and that the accuracy of many of his operations is surprizing. The other works of Geber now extant are, 1. “His Astronomy, or demonstrative work of Astrology” in nine books, printed at Nuremberg in 1533. 2; “His three Books on Alchymy,” published at Strasburg, with one “De investigatione perfect! Magisterii,” in 1530 and also in Italy from a ms. in the Vatican. 3. “On the Investigation of the truth of Metals, and on Furnaces, with other works,” Nuremberg, 1545. 4. “A book called Flos Naturarum,” published in 1473. 5. Also his “Chymica” printed by Perna, with the chemical works of Avicenna. All these were published in English at Leyden, by Richard Russel in 1668. His Almagest is also extant in Arabic. As a specimen of his language, he used to say, “my object is to cure six lepers,” meaning that he wished to convert six inferior metals into gold.

As Gellibrand was inclined to puritan principles, while he was engaged in this work, his servant, William Beale, by his encouragement, published an al manack for the year 1631, in which the popish saints, usually put into our kalendar, and the Epiphany, Annunciation, &c. were omitted; and the names of other saints and martyrs, mentioned in the book of martyrs, were placed in their room as they stand in Mr. Fox’s kalendar. This gave offence to Dr. Laud, who, being then bishop of London, cited them both into the high-commission court. But when the cause came to a hearing, it appeared, that other almanacks of the same kind had formerly been printed; on which plea they were both acquitted by abp. Abbot and the whole court, Laud only excepted; which was afterwards one of the articles against him at his own trial. This prosecution jdid not hinder Geliibrand from proceeding in his friend’s work, which he completed in 1632; and procured it to be printed by the famous Ulacque Adrian, at Gouda in Holland, in 1633, folio, with a preface, containing an encomium of Mr. Brigg’s, expressed in such language as shews him to have been a good master of the Latin tongue. Geliibrand wrote the second book, which was translated into English, and published in an English treatise with the same title, “Trigonometria Britaonica, &c.” the -first part by John Newton in 1658, folio. While he was abroad on this business, he had some discourse with Lansberg, aa eminent astronomer in Zealand, who affirming that he was fully persuaded of the truth of the Cop^ernican system, our author observes, “that this so styled a truth he should receive a an hypothesis; and so be easily led on to the consideration of the imbecility of man’s apprehension, as not able rightly to conceive of this admirable opifice of God, or frame of the world, without falling foul on so great an absurdity:” so firmly was he fixed in his adherence to the Ptolemaic system. He wrote several things after this, chiefly tending to the improvement of navigation, which would probably have been further advanced by him, had his life been continued longer; but he was untimely carried offby a fever in 1636, in his thirty-ninth year, and was buried in the parish church of St. Peter le Poor, Broadstreet. He had four younger brothers, John, Edward, Thomas, and Samuel; of whom John was his executor, and Thomas was a major in the parliamentary army, was an evidence in archbishop Laud’s trial; and was grandfather to Samuel Gellibrand, esq. who, about the middle of last century, was nnder-secretary in the plantation-office.

The reputation of, these two works, whatever may now be thought of them, procured him the professorship of philosophy in the university of Turin in 1750, and he was also appointed a fellow of the royal academy which was instituted at that time. Many excellent memoirs from his pen are printed in the first five volumes of its transactions, published in 1759. In 1757 he published what was thought the most useful of all his works, the “Introduction to the Study of Religion,” against the infidel writers of his day. The merit of this work induced the pope Benedict XIV. to recommend him to his Sardinian majesty, to be tutor to the prince royal, afterwards the late (abdicated) king of Sardinia. For the use of his royal pupil he wrote an excellent treatise on duels; and during the time he was employed in the court of Turin, published three works in confutation of some paradoxes of as many eminent French writers,Melon, Montesquieu, and Rousseau. He confuted Melon in his doctrine, that luxury contributes tcr the prosperity of nations; Montesquieu, in his principle that monarchic governments can subsist without virtue; and Rousseau, in the whole of his system of education, exhibited in the Emile. This last appears to be the best. Rousseau himself acknowledged that it was the only book written against him which he thought worthy of being read to the end, a compliment, however, as much to himself as to Gerdil, and containing more vanity than truth. This work was translated into English, and published at London in 1764, under the title “Reflections on Education; relative both to theory and practice,” &c. 2 vols. 12mo. Gerdil afterwards diminished in some degree his general reputation by publishing a work on the phenomena of capillary tubes, in which he combated the doctrine of attraction. On this occasion the late celebrated astronomer La Lande said, *' Gerdil is learned in many other branches of science; and his reputation may safely dispense with this work.“In 1777, on the nomination of his Sardinian majesty, Gerdil was made a cardinal, and consequently left Turin for Rome, where, however, he lived in a state of comparative retirement, and is said to have been dissatisfied with the political conduct of the court of Rome, from which he foresaw many evils to the church. In 1801 he warmly opposed the intended negociations with the French consular government, and treated Buonaparte’s proposal for a concordate as an impudent hypocritical farce, and therefore openly dissented from it. It was generally reported that he told the late pope, Pius VI. that” by the signature of the concordate he had signed the destruction of religion," which in one sense was probably true. Gerdil was a catholic of the old school, and with him there was no religion but that of the church, and no power but that of the court of Rome. These predominant sentiments of his mind are not unfrequently discoverable in his works. He died at Rome, Aug. 17, 1802, much regretted by his admirers, by his colleagues, and by the public at large. He was buried by his own desire in the plainest manner, in the church of his convent of St. Charles, at Cattinari. The year after his death a complete edition of his works was published at Bologna, in 6 vols. 4to. They are written in Latin, Italian, and French.

, the principal event in whose life is the reformation he introduced in the Roman calendar, was born at Bologna in 1502. His name before his promotion was Hugh Buoncompagno. He was brought up to the study of the civil and canon law, which he taught in his native city with uncommon reputation. He was afterwards appointed judge of the court of commerce at Bologna. From this city he removed to Rome, where, after various preferments, he was on the death of Pius V. in 1572, unanimously elected his successor, and at his consecration he took the name of Gregory XIII. His reformation of the calendar, was according to a method suggested by Lewis Lilio, a Calabrian astronomer, which after his death was presented to the pope by his brother. This method, which was immediately adopted in all catholic countries, but was rejected by the protestants and by the Greeks, was intended to reform the old or Julian year, established by Julius Caesar, which consisted of'365 days 6 hours, or 365 difys and a quarter, that is three years of 365 days each, and the fourth year of 366 days. But as the mean tropical year consists only of 365 days 5 hours 48 minutes 57 seconds, the former lost 11 minutes 3 seconds every year, which in the time of pope Gregory had amounted to 10 <lays, and who, by adding these 10 days, brought the account of time to its proper day again, and at the same time appointed that every century after, a day more should be added, thereby making the years of the complete centuries, viz. 1600, 1700, 1800, &c. to be common years of 365 days each, instead of leap-years of 366 days, which makes the mean Gregorian year equal to 365 days 5 hours 45 minutes 36 seconds. This computation was not introduced into the account of time in England, till 1752, when the Julian account had lost 11 days, and therefore the 3d of September, was in that year by act of parliament accounted the 14th, thereby restoring the 11 days which had thus been omitted.

He continued at Edinburgh till 1691, when, hearing of Dr. Bernard’s intention to resign the Savilian professorship of astronomy at Oxford, he left Scotland, and, coming to London, was admitted a member of the royal society: and paid his addresses to sir Isaac Newton, who took the first opportunity of recommending him to Mr. Flamstead (master of the mathematical school in Christ’s-hospital, London), with a letter, recommending his mathematical merit above all exception in these terms: “Sir, it. is almost a fortnight since I intended, with Mr. Paget and another friend or two, to have given you a visit at Greenwich; but sending to the Temple coffee-house, I understood you had not been in London for two or three weeks before, which made me think you were retired to your living for a time. The bearer hereof, Mr. Gregory, mathematic professor of Edinburgh college, in Scotland, intended to have given you a visit with us. You will find him a very ingenious person, and a good mathematician, worth your acquaintance.” In proceeding, he mentions our author as a fit person, in case of Mr. Flamstead’s death, to carry on his astronomical views. Thus recommended, the royal astronomer used his best interest to procure him success at Oxford, where he was elected astronomy-professor this year, having been first admitted of Baliol college, and incorporated M. A. February 8, and he was created M. D. on the

, a. physician, astronomer, and mathematician, and like his countryman, friar Bacon, violently suspected of magic, lived in the fourteenth century, He studied at Merton college, Oxford; and, probably to escape the disagreeable consequences of such suspicions, went into France, where he devoted himself entirely to the study of medicine, first at Montpelier, and then at Marseilles. In this eity he fixed his residence, and lived by the practice of his profession, in which he acquired much skill and eminence. There is no greater proof of his genius, besides the imputations he laboured under in his youth, than his assiduously pursuing the method instituted by the Greek physicians, of investigating the nature and cause of the disease and the constitution of the patient. The time of his death is not known; but we are told that he was an old man in 1350, and that he had a son, who was first an abbot of canons regular at Marseilles, and at length arrived at the pontificate under the name of Urban V. Bale and Pits both give lists of his works, none of which are known to be extant.

The use of astronomy in navigation unavoidably draws the astronomer’s thoughts upon that important subject; and accordingly we find Gunter discovering a new variation in the magnetic needle, or the mariner’s compass, in 1 Gilbert, in the beginning of that century, had incontestibly established the first discovery of the simple variation; after which the whole attention of the studious in these matters was employed in settling the rule observed by nature therein, without the least apprehension or suspicion of any other; when our author, making an experiment at Deptford in the above year, found that the direction of the magnetism there had moved no less than five degrees within two minutes, in the space of forty-two years. The fact, however, was so surprising, and so contrary to the opinion then universally received of a simple variation only, which had satisfied and bounded all their curiosity, that our author dropt the matter apparently, expecting, through modesty, an error in his observation to have escaped his notice in his experiment. But afterwards, what he had done induced his successor at Gresham, Mr. Gellibrand, to pursue it; and, the truth of Gunter’s experiment being confirmed by a second, farther inquiry was made, which ended in establishing the fact. We have since seen Halley immortalize his name, by settling the rule of it in the beginning of the last century.

, an eminent English philosopher and astronomer, was born at Haggerston, in the parish of St. Leonard, Shoreditch, near London, October 29, 1656. His father, a wealthy soap-boiler in Winchester-street, put him to St. Paul’s school, under the learned Dr. Thomas Gale, but his h'rst tutor is said to have been his father’s apprentice, who taught him writing and arithmetic at nine years old. At school he not only excelled in all parts of classical learning, but made such uncommon progress in mathematics, that, as Wood says, he had perfectly learnt the use of the celestial globe, and could make a complete dial; and we are informed by Halley himself, that he observed the change of the variation of the magnetic needle at London, in 1672, that is, one year before he left school. In 1673 he was entered a commoner of Queers-college, in Oxford, where he applied himself to practical and geometrical astronomy, in which he was greatly assisted by a curious apparatus of instruments which his father, willing to encourage his son’s genius, had purchased for him. At nineteen he began to publish new observations and discoveries, and continued to do so to the end of a very long life; nor did he distinguish himself less in the practical part of the science. Several observations made by him concerning a spot in the sun, seen at Oxford in July and August 1676, were published, with others by Flamsteed upon the same subject, in the Philosophical Transactions. By these the motion of the sun round its own axis, a phenomenon till then not well ascertained, was finally determined. The same year he likewise observed there, on Aug. 21, a.n occultation of Mars by the Moon, which he made use of afterwards, with others, in settling the longitude of the Cape of Good Hope against the objections of the French astronomers.

, a great astronomer, who flourished about 480 years before Christ, corrected the cycle of eight years invented by Cleostratus, and in its stead proposed a new one of nine years, in which he supposed that the sun and moon returned to the same point; but this cycle of Harpalus was afterwards altered by Meton, about the year 444 B. C. who added ten years to it, which cycle is still in use, and called “The Golden Number.”

, an eminent mathematician, was born at Oxford, or, as Anthony Wood expresses it, “turn-; bled out of his mother’s womb in the lap of the Oxonian Muses,” in 1560. Having been instructed in grammarlearning in that city, he became a commoner of St. Maryhall, where he took the degree of B. A. in 1579. He had then so distinguished himself, by his uncommon skill in mathematics, as to be recommended soon after to sir Walter Raleigh as a proper preceptor to him in that science. Accordingly, that noble knight became his first patron, took him into his family, and allowed him a handsome pension. In 1585 he was sent over by sir Walter with his first colony to Virginia; where, being settled, he was employed in discovering and surveying that country, in observing what commodities it produced, together with the manners and customs of its inhabitants. He published an account of it under this title, “A brief and true Report of the Newfoundland of Virginia;” which was reprinted in the third voyage of Hakluyt’s “Voyages.” Upon his return to England, he was introduced by his patron to the acquaintance of Henry earl of Northumberland who, “finding him,” says Wood, “to be a gentleman of an affable and peaceable nature, and well read in the obscure pan of learning,” allowed him a yearly pension of 120l. About the same time, Robert Hues, well known by his ' Treatise upon the Globes,“and Walter Warner, who is said to have communicated to the famous Harvey the first hint concerning the circulation of the blood, being both of them mathematicians, received pensions from him of less value, ^o that in 1606, when the earl was committed to the Tower for life, Harriot, Hues, and Warner, were his constant companions, and were usually called the earl of Northumberland’s Magi. They had a table at the earl’s charge, who did constantly converse with them, to divert the melancholy of his confinement; as did also sir Walter Raleigh, who was then in the Tower. Harriot lived for some time at Sion-college, and died in London, July 2, 1621, of a cancer in his lip. He was universally esteemed on account of his learning. When he was but a young man, he was styled by Mr. Hakluyt” Juvenis in disciplinis mathematicis excellens;“and by Camden,” Mathematicus insignis.“A ms. of his, entitled” Ephemeris Chryrometrica,“is preserved in Sion-college library and his” Artis Analytic* Praxis“was printed after his death, in a thin folio, and dedicated to Henry earl of Northumberland. Des Cartes is said to have been obliged to this book for a great many improvements in algebra, which he published to the world as his own, a fact that has been amply proved, in the astronomical ephemeris for 17vS8, by Dr. Zach, astronomer to the duke of Saxe Gotha, from manuscripts which he found in 1784 at the seat of the earl of Egremont at Petworth, a descendant of the above-mentioned earl of Northumberland. These papers also show that Mr. Harriot was an astronomer as well as an algebraist, As to his religion, Wood says, that,” notwithstanding his great skill in mathematics, he had strange thoughts of the Scripture, always undervalued the old story of the Creation of the World, and could never believe that trite position, * Ex nihilo nihil fit.‘ He made a Philosophical Theology, wherein he cast off the Old Testament, so that consequently the New would have uo foundation. He was a deist; and his doctrine he did impart to the earl, and to sir Walter Raleigh, when he was compiling the ’ History of the World,' and would controvert the matter with eminent divines of those times: who, therefore, having no good opinion of him, did look on the manner of his death, as a judgment upon him for those matters, and for nullify, ing the Scripture.“Wood borrowed all this from Aubrey, without mentioning his authority; and it has been answered, that Harriot assures us himself, that when he was with the first colony settled in Virginia, in every town where he came,” he explained to them the contents of the Bible, &c. And though I told them,“says he,” the book materially and of itself was not of such virtue as I thought they did conceive, but only the doctrine therein contained; yet would many be glad to touch it, to embrace it, to kiss it, to hold it to their breasts and heads, and stroke over all their bodies with it, to shew their hungry desires of that knowledge which was spoken of." To which we may add, that, if Harriot was reputed a deist, it is by no means probable that Dr. Corbet, an orthodox divine* and successively bishop of Oxford and Norwich, sending a poem, dated December 9, 1618, to sir Thomas Aylesbury, when the comet appeared, should speak of

, a most accurate mechanic, the celebrated inventor of the famous time-keeper for ascertaining the longitude at sea, and also of the compound or gridiron-pendulum; was born at Foulby, near Pontefract in Yorkshire, in 1693. His father was a carpenter, in which profession the son assisted; occasionally also, according to the miscellaneous practice of country artists, surveying land, and repairing clocks and watches; and young Harrison always was, from his early childhood, greatly attached to any machinery moving by wheels. In 1700 he removed with his father to Barrow, in Lincolnshire; where, though his opportunities of acquiring knowledge were very few, he eagerly improved every incident from which he might collect information frequently employing all or great part of his nights in writing or drawing and he always acknowledged his obligations to a clergyman who came every Sunday to officiate in the neighbourhood, who lent him a ms copy of professor Sanderson’s lectures; which he carefully and neatly transcribed, with all the diagrams. His native genius exerted itself superior to these solitary disadvantages; for, in 1726, he had constructed two clocks, mostly of wood, in which he applied the escapement and compound pendulum of his own invention: these surpassed every thing then made, scarcely erring a second in a month. In 1728 he came up to London with the drawings of a machine for determining the longitude at sea, in expectation of being enabled to execute one by the board of longitude. Upon application to Dr. Halley, the astronomer royal, he referred him to Mr. George Graham, who advised him to make his machine before applying to that board. He accordingly returned home to perform his task; and in 1735 came to London, again with his first machine, with which he was sent to Lisbon the next year to make trial of it. In this short voyage he corrected the dead reckoning about a degree and a half; a success which procured him both public and private encouragement. About 17 '69 he completed his second machine, of a construction much more simple than the former, and which answered much better: this, though not sent to sea, recommended Mr. Harrison yet stronger to the patronage of his friends and the public. His third machine, which he produced in 1749, was still less complicated than the second, and more accurate, as erring only 3 or 4 seconds in a week. This he conceived to be the ne plus ultra of his attempts; but, by endeavouring to improve pocket-watches, he found the principles he applied to surpass his expectations so much, as to encourage him to make his fourth time-keeper, which is in the form of a pocket-watch, about six inches diameter. With this time-keeper his son made two voyages, the one to Jamaica, and the other to Barbadoes in which experiments it corrected the longitude within the nearest limits required by the act of the 12th of queen Anne; and the inventor had, therefore, at different times, more than the proposed reward, receiving from the board of longitude at different times almost 24,000l. besides a few hundreds from the East India company, &c. These four machines were given up to the board of longitude. The three former were not of any use, as all the advantages gained by making them, were comprehended in the last: being worthy however of preservation, as mechanical curiosities, they are deposited in the royal observatory at Greenwich. The fourth machine, emphatically distinguished by the name of The Time-keeper, was copied by the ingenious Mr. Kendal; and that duplicate, during a three years circumnavigation of the globe in the southern hemisphere by captain Cook, answered as well as the original.

, a learned astronomer, and member of most of the learned societies of Europe, was born in 1720, at Chemnitz, in Hungary, and first educated at Neusol. Having in 1738 entered the society of the Jesuits, he was sent by them to the college of Vienna, where, during his philosophical studies, he displayed a genius for mechanics, and employed his leisure hours in constructing water-clocks, terrestrial and celestial globes, and other machines. In 1744 and 1745 he studied mathematics, now become his favourite pursuit, under the celebrated Froelich, and not only assisted Franz, the astronomer of the Jesuits’ observatory, in his labours, but also in arranging the museum for experimental philosophy. At the same time he published a new edition of Crevellius’s “Arithmetica numeralis et literalis,” as a text-book. In 1746 and 1747 he taught Greek and Latin in the catholic school of Leutschau, in Hungary, and returning to Vienna in the latter year, was employed as the instructor in the mathematics, and the art of assaying, of several young men destined for offices in the Hungarian mines. In 1750 he published, “Adjumentum memoriae manuale Chronologicogenealogico-historicum,” which has since been translated into various languages, and of which an enlarged edition appeared in 1774. In 1751 and 1752 he obtained the priesthood, completed his academical degrees, and was appointed professor of mathematics at Clausenburg. Here he published his “Elementa Arithmetical 1 for the use of his pupils, and had prepared other works, when he was, in Sept. 175”2, invited to Vienna, and appointed astronomer and director of the new observatory, in the building of which he assisted, and made it one of the first in Europe, both as to construction and apparatus. From 1757 to 1767 he devoted himself entirely to astronomical observations and calculations for the “Ephemerides,” each volume of which, published annually, contained evident proofs of his assiduity. About the same time he published a small work, entitled “An Introduction towards the useful employment of Artificial Magnets.”

, or Hevelke, a celebrated astronomer and mathematician, was born at Dantzic January 28, 1611. His parents, who were of rank and fortune, gave him a liberal education; in which he discovered early a propensity to natural philosophy and astronomy. He studied mathematics under Peter Crugerus, in which he made a wonderful progress; and learned also to draw, to engrave, and to work both in wood and iron in such a manner as to be able to frame mechanical instruments. In 1630 he set out upon his travels, on which he spent four years, visiting Holland, England, France, and Germany; and on his return was so taken up with civil affairs, that he was obliged to intermit his studies for some years, until his master, Crugerus, who foresaw his future fame, recalled him to the study of astronomy; and in 1639 Hevelius began to apply himself entirely to it, by building an observatory upon the top of his house, which he furnished with instruments for making the most accurate observations. He constructed excellent telescopes himself, and began his observations with the moon, whose various phases and spots he noted very accurately; “with a view,” as he says, “of taking lunar eclipses with greater exactness, and removing those difficulties which frequently arise for want of being able to settle more precisely the quantity of an eclipse.” When he had finished his course of observations, and prepared a great number of fine engravings, he published his work at Dantzick, 1647, under the title of “Selenographia, sive, Luna3 descriptio;” to which he added, by way of appendix, the phases of the other planets, as they are seen through the telescope, with observations upon them, upon the spots of the sun and Jupiter in particular; all engraved by himself upon copper, and distinctly placed before the eyes of the reader. At the entrance of this work there is a handsome mezzotinto of himself by Falek, as he then was, in his thirty-sixth year, with a just encomium, although in bad Latin verse.

After this, Hevelius continued to make his observations upon the heavens, and to publish, from time to time, whatever he thought might tend to the advancement of astronomy. In 1654 he published two epistles; one to the famous astronomer Ricciolus, “De motu Lunae libratorio;” another to the no less famous Bulialdus, “De utriusque luminaris defectu.” In 1656, a dissertation “De natura Saturni faciei, ejusque phasibus certa periodoredeuntibus.” In 1661, “Mercurius in sole visus.” In 1662, “Historiola de nova stella in collo Ceti.” In 1665, “Prodromus Cometicus, or the history of a Comet, which appeared in 1664.” Jn 1666, “The History of another Comet, which appeared in 1665;” and, in 1668, “Cometographia, cometarum naturam, et omnium a mundo condito historian! exhibens.” He sent copies of this work to several members of the royal society at London, and among the rest to Hooke; who in return sent Hevelius a description of the dioptric telescope, with an account of the manner of using it; and at the same time recommended it to him as greatly preferable to telescopes with plain sights. This gave rise to a dispute between them; the point of which was, “whether distances and altitudes could be taken with plain sights nearer than to a minute.” Hooke asserted that they could not; but that, with an instrument of a span radius, by the help of a telescope, they might be determined to the exactness of a second. Hevelius, on the other hand, insisted, that, by the advantage of a good eye and long use, he was able with his instruments to come up even to that exactness; and appealing to experience and facts, sent by Way of challenge eight distances, each between two different stars, to be examined by Hooke. Thus the affair rested for some time with outward decency, but not without some inward animosity. In 1673 Hevelius published the first part of his “Machina Ccelestis,” as a specimen of the exactness both of his instruments and observations; and sent several copies as presents to his friends in England, but omitted Hooke. This, it is supposed, occasioned Hooke to print, in 1674, “Animadversions on the first part of the Machina Ccelestis;” in which he treated Hevelius with great disrespect, and threw out several unhandsome reflections, which were greatly resented; and the dispute grew afterwards so public, and rose to such a height, that, in 1679, Halley went at the request of the royal society, to examine both the instruments and the observations made with them. Halley gave a favourable judgment of both, in a letter to Hevelius; and Hooke, merely from his mode of managing the controversy, was universally condemned, though the preference has since been given to telescopic sights. Hevelius, however, could not be prevailed with to make use of them: whether he thought himself too experienced to be informed by a young astronomer, as he considered Hooke; or whether, having made so many observations with plain sights, he was unwilling to alter his method, lest he might bring their exactness into question; or whether, being by long practice accustomed to the use of them, and not thoroughly apprebending the use of the other, nor well understanding the difference, is uncertain. Besides Halley’s letter, Hevelius received many others in his favour, which he took the opportunity of inserting among the astronomical observations in his “Ami us Ciimuctericus,” printed in 1685. In a long preface prefixed to this work, he spoke with more conn“­dence and greater indignation than he had done before; and particularly exclaimed against Hooke’s dogmatical and magisterial manner of assuming a kind of dictatorship over him. This revived the dispute, and caused several learned men to engage in it. The book itself being sent to the royal society, an account was given of it at their request by Dr. Wallis who, among other things took notice, that” Hevelius’s observations had been misrepresented, since it appeared from this book, that he could distinguish by plain sights to a small part of a minute.“About the same time, Molynea;jx also wrote a letter to the society in vindication of Hevelius against Hooke’s” Animadversions.“Hooke drew up an answer to this letter, which was read likewise before the society; in which he observed,” that he was not the aggressor, and denied that he had intended to depreciate Hevelins."

, a celebrated ancient astronomer, was born at Nice in Bithynia, and flourished between the 154th and 163d olympiads; or between 160 and 125 B. C. as we learn from tjie astronomical observations he tnade in that space of time. He is supposed to have been the first who, from vague and scattered observations, reduced astronomy to a science, and prosecuted the study of it systematically. Pliny, who always mentions him in terms of high commendation, says he was the lirst who attempted to take the number of the fixed stars, and his catalogue is preserved in Ptolemy’s “Almagest,” where they are all noted according to their longitudes and apparent magnitudes. Pliny places him amongst those men of a sublime genius, who, by foretelling the eclipses, taught mankind, that they ought not to be frightened at these phenomena. Thales was the first among the Greeks, uho could discover when there was to be an eclipse. Sulpitms Gailns among the Romans begun to succeed in this kind of prediction; and gave an essay of his skill very seasonably, the day before a battle was fought. "After these two, Hipparchus foretold the course of the sun and moon for 600 years calculated according to the different manner of reckoning the months, days, and hours, used by several nations, and for the different situations of places. Pliny admires him for taking an account of all the stars, and for acquainting us with their situations am! magnitudes. Hipparchus is also memorable for being the first who discovered the precession of the equinoxes.

, an eminent French mathematician and astronomer, was born at Paris, March 18, 1640. His father Laurence, who was painter in ordinary to dm king, professor in the academy of painting and sculpture, and much celebrated, intended him also for the same occupation; and with that view taught him the principles of design, and some branches of mathematics, but died when Philip was no more than seventeen. Falling afterwards into a bad habit of body, he projected a journey into Italy; which he conceived might contribute not less to the recovery of his health, than to bring him to perfection in his art. He accordingly set out in 1660, and soon found himself well enough to contemplate the remains of antiquity, with which Italy abounds, and also to study geometry, to which he had indeed more propensity than to painting, and which soon afterwards engrossed him entirely. The retired manner in which he spent his time in Italy, very much suited his disposition; and he would willingly have continued longer in that country, but for the importunity of his mother, who prevailed upon him to return, after an absence of about four years.

, a learned English gentleman, well known in the history of British India, was the son of Zephaniah Holwell, timber-merchant and citizen of London, and grandson of John Holwell, a mathematical writer of much fame in the seventeenth century. The father and grandfather of this John Holwell both fell in support of the royal cause during the usurpation, and the family estate of Holwell-hall, in Devonshire, was lost to their descendants for ever; for although Mr. Holwell applied to king Charles at the restoration, the only recompense he obtained was to be appointed royal astronomer and surveyor of the crown lands, and the advancement of his wife to a place of some honour, but of little emolument, about the person of the queen. Some years after he was appointed mathematical preceptor to the duke of Monmouth, for whom he conceived a warm attachment, and, believing him to be the legitimate sou of the king, was induced to take a very active and imprudent part against the succession of the duke of York, which in the end proved his ruin. Having published in 1683 a small Latin tract called “Catastrophe Mundi,” which was soon after translated, and is a severe attack on the popish party, he was marked for destruction as soon as the duke of York came to the throne. Accordingly, in 1685, it was contrived that, in quality of surveyor to the crown, he should be sent to America, to survey and lay down a chart of the town of New York; and at the same time secret orders were sent to the government agents there, to take some effectual means to prevent his return. In consequence of this, it is said, that he had no sooner executed his commission, than he died suddenly, and his death was attributed, at the time and on the spot, to the application of poison administered to him in a dish of coffee. His son was father to the subject of the present article.

, a celebrated chemist, was born at Batavia in the island of Java, Jan. 3, 1652, the son of John Homberg, a Saxon gentleman, governor of the arsenal of that place. His father at first put him into the army, but soon after quitting the service of the Dutch, and a military life, brought him to Amsterdam, where he settled. He was now educated, by paternal indulgence, at Jena and Leipsic, for the law, and was received as an advocate in 1674 at Magdebourg, but the sciences seduced him from the law: in his walks he became a botanist, and in his nocturnal rambles an astronomer. An intimacy with Otto de Guericke, who lived at Magdebourg, completed his conversion, and he resolved to abandon his first profession. Otto, though fond of mystery, consented to communicate his knowledge to so promising a pupil; but as his friends continued to press him to be constant to the law, he soon quitted Magdebourg, and went into Italy. At Padua and Bologna he pursued his favourite studies, particularly medicine, anatomy, botany, and chemistry. One of his first efforts in the latter science was the complete discovery of the properties of the Bologna stone, and its phosphoric appearance after calcination, which Casciarolo had first observed. The efforts of Hombergr in several scientific inquiries, were pursued at Rome, in France, in England with the great Boyle, and afterward in Holland and Germany. With Baldwin and Kunckel he here pursued the subject of phosphorus. Not yet satisfied with travelling in search of knowledge, he visited the mines of Saxony, Hungary, Bohemia, and Sweden. Having materially improved himself, and at the same time assisted the progress of chemistry at Stockholm, he returned to Holland, and thence revisited France, where he was quickly noticed by Colbert. By his interposition, he was prevailed upon to quit his intention of returning to Holland to marry, according to the desire of his father, and fixed himself in France. This step also alienated him from his religion. He renounced the Protestant communion in 1682, and thus losing all connexion with his family, became dependent on Louis XIV. and his minister. This, however, after the death of Colbert in 1683, became a miserable dependence; men of learning and science were neglected as much as before they had been patronized; and Homberg, in 1687, left Paris for Rome, and took up the profession of physic. He now pursued and perfected his discoveries on phosphorus, and prosecuted his discoveries in pneumatics, and other branches of natural philosophy. Finding, after some time, that the learned were again patronized at Paris, he returned there in 1690, and entered into the academy of sciences tinder the protection of M. de Bignon. He now resumed the study of chemistry, but found his finances too limited to carry on his experiments as he wished, till he had the good fortune to be appointed chemist to the duke of Orleans, afterwards regent. In this situation he was supplied with the most perfect apparatus, and all materials for scientific investigation. Among other instruments, the large burning mirror of Tschirnaus was given to his care, and he made with it the most interesting experiments, on the combustibility of gold and other substances. In examining the nature of borax he discovered the sedative salt, and traced several remarkable properties of that production. Pleased with the researches of his chemist, the duke of Orleans in 1704 appointed him his first physician. About the same time he was strongly solicited by the elector palatine to settle in his dominions, but he was too much attached to his present patron to quit Paris, and was besides not without an inclination of a more tender kind for mademoiselle Dodart, daughter to the celebrated physician of that name. He married her in 1708, though hitherto much averse to matrimony; but enjoyed the benefit of his change of sentiments only seven years, being attacked in 1715 with a dysentery, of which he died in September of that year.

Homer had the most sublime and universal genius that the world has ever seen; and though it is an extravagance of enthusiasm to say, as some of the Greeks did, that all knowledge may be found in his writings, no man penetrated deeper into the feelings and passions of humaa nature. He represents great things with such sublimity, and inferior objects with such propriety, that he always makes the one admirable, and the other pleasing. Strabo, whose authority in geography is indisputable, assures us, that Homer has described the places and countries, of which he gives an account, with such accuracy, that no man can imagine who has not seen them, and no man can observe without admiration and astonishment. Nothing, however, can be more absurd, than the attempts of some critics, who have possessed more learning and science than taste, to rest the merit of Homer upon the extent of his knowledge. An ancient encomiast upon Homer proves him to have possessed a perfect knowledge of nature, and to have been the author of the doctrine of Thales and Xenophanes, that water is the first principle of all things, from his having called Oceanus the parent of nature; and infers, that he was acquainted with Empedocles’ doctrine of friendship end discord, from the visit which Juno pays to Oceanus and Thetis to settle their dispute: because Homer represents Neptune as shaking the earth, he concludes him to have been well acquainted with the causes of earthquakes; and because he speaks of the great bear as never touching the horizon, he makes him an eminent astronomer. The truth is, the knowledge of nature, which poetry describes, is very different from that which belongs to the philosopher. It would be easy to prove, from the beautiful similes of Homer, that he was an accurate observer of natural appearances; and to show from his delineation of characters, that he was intimately acquainted with human nature. But he is not, on this account, to be ranked with natural philosophers or moralists. Much pains have been taken to prove, that Homer expresses just and sublime conceptions of the divine nature. And it will be acknowledged, that, in some passages, he speaks of Jupiter in language which may not improperly be applied to the Supreme Deity. But, if the whole fable of Jupiter, as it is represented in Homer, be fairly examined, it will be very evident, either that he had not just conceptions of the divine nature, or that he did not mean to express them in the portrait which he has drawn of the son of Saturn, the husband of Juno, and the president of the council of Olympus. It would surely have been too great a monopoly of perfection, if the first poet in the world had also been the first philosopher. Homer has had his enemies; and it is certain, that Plato banished his writings from his commonwealth; but lest this should be thought a blemish upon the memory of the poet, we are told that the true reason was, because he did not esteem the common people to be capable readers of them. They would be apt to pervert his meaning, and have wrong notions of God and religion, by taking his bold and beautiful allegories in a literal sense. Plato frequently declares, that he loves and admires him as the best, the most pleasant, and divine of all poets, and studiously imitates his figurative and mystical way of writing: and though he forbad his works to be read in public, yet he would never be without them in his closet. But the most memorable enemy to the merits of Homer was Zoilus, a snarling critic, who frequented the court of Ptolemy Philadelphus, king of Egypt, and wrote ill-natured notes upon his poems, but received no encouragement from that prince; on the contrary, he became universally despised for his pains, and was at length put, as some say, to a most miserable death. It is said that though Homer’s poems were at first published all in one piece, and not divided into books, yet every one not being able to purchase them entire, they were circulated in separate pieces; and each of those pieces took its name from the contents, as, “The Battle of the Ships;” “The Death of Dolon;” “The Valour of Agamemnon;” “The Grot of Calypso;” “The Slaughter of the Wooers,” &c. nor were these entitled books, but rhapsodies, as they were afterwards called, when they were divided into books. Homer’s poems were not known entire in Greece before the time of Lycurgus; whither that law-giver being in Ionia carried them, after he had taken the pains to transcribe them from perfect copies with his own hands. This may be called the first edition of Homer that appeared in Greece, and the time of its appearing there was about 120 years before Rome was built, that is, about 200 years after the time of Homer. It has been said, that the “Iliad” and “Odyssey” were not composed by Homer in their present form, but only in separate little poems, which being put together and connected afterwards by some other person, make the entire works they now appear; but this is so extravagant a conceit that it scarceJy deserves to be mentioned.

In 1668, Hevelius, the famous astronomer at Dantzick, presented a copy of his “Cometographia” to Hooke, in acknowledgment for an handsome compliment which Hooke had paid to him on account of his “Selenographia,” printed in 1647; and Hooke, in return, sent Hevelius a description of the dioptric telescope, with an account of his manner of using 1 it, and recommended it to him as preferable to those with plain sights. This circumstance gave rise to a great dispute betwee'n them, noticed in our account of Hevelius, hi which many learned men afterwards engaged, and which Hooke so managed, as to be univeraiiy condemned, though it has since been agreed that he had the best side of the question. In 1671 he attacked sir Isaac Newton’s “New Theory of Light and Colours;” where, though he was forced to submit in respect to the argument, he is said to have couie off with a better reputation than in the former instance. The Royal Society having begun their meetings at Gresham-college, in Nov. 1674, the committee in December allowed him 40l. to erect a turret over part of his lodgings, for proving his instruments, and making astronomical observations; and the year following he published “A Description of Telescopes, and some other instruments,” made by him, with a postscript, complaining of some injustice done him by Oldenburg, the publisher of the “Philosophical Transactions,” in regard to his invention of pendulum watches. This charge drew him into a dispute with that gentleman, which ended in a declaration of the Royal Society in their secretary’s favour. Oldenburg dying in Aug. 1677, Hooke was appointed to supply his place, and began to take minutes at the meeting in October, and published seven numbers of the “Philosophical Collections,” which have been always considered as a part of the “Philosophical Transactions.” Soon after this be grew more reserved than formerly, and though he read his Cutlerian lectures, and often made experiments, and shewed new inventions before the Royal Society, yet'he seldom left any account of them to be entered in their registers, designing, as he said, to fit them for himself, and make them public, which however he never performed. In 1636, when sir Isaac Newton’s Principia were published, Hooke, with that jealousy which was natural to him, claimed priority respecting the idea of gravitation. Newton, with a candour equally natural to him, admitted his claim, but shewed at the same time that Hooke’s notion of gravitation was different from his own, and that it did not coincide with the phenomena. In reality, the notion of gravitation is as ancient at least as the days of Lucretius, and is particularly notice<i by Kepler. Newton’s merit consisted, not in ascribing the planetary motions to gravitation, but in determining the law which gravitation follow:;, and in shewing that it exactly accounts for all the planetary phenomena, which no other system. does.

, a celebrated Danish astronomer, and professor of that science at Copenhagen, was born at Laegsted, in Jutland, in 1679. He studied at Aalburg under very unfavourable circumstances, beingobliged, at the same period, to submit to various kinds of labour. In 1714, he was appointed professor of mathematics at Copenhagen, and in 1725 he was elected a member of the Danish academy of sciences. He died in 1764. He was author of many works connected with his favourite pursuits, among which were “Copernicus Trinmphans, sive de Parallaxi Orbis Annui;” in which he shews himself an enthusiast for the system of Copernicus; the “Elements of Astronomy;” and “the Elements of Mathematics;” but he is best known in this country by his “Natural History of Iceland,” fol. 1758. His mathematical works were published in four vols, 4to, Copenhagen, 1735, &c.

, an English astronomer, and memorable for being the first who had observed the passage of Venus over the sun’s disk, was born at Toxteth in Lancashire, about 1619. From a school in the country, where he acquired grammar-learning, he was sent to Emanuel-college in Cambridge, and there spent some time in academical studies. About 1633, he began with real earnestness to study astronomy: but living at that time with his father at Toxteth, in very moderate circumstances, and being destitute of' books and other assistances for the prosecution of this study, he could not make any considerable progress. He spent some of his first years in studying the writings of Lansbergius, of which he repented and complained afterwards; neglecting in the mean time the more valuable and profitable works of Tycho Brahe, Kepler, and other excellent astronomers. In 16^6, he contracted an acquaintance with Mr. William Crabtree of Broughton near Manchester, and was engaged in the same studies; but living at a considerable distance from each other, they could have little correspondence except by letters. These, however, they frequently exchanged, communicating their observations to one another; and they sometimes consulted Mr. Samuel Foster, professor of astronomy at Gresham-college in London. Horrox having now obtained a companion in his studies, assumed new spirits. Procuring astronomical instruments and books, he applied himself to make observations; and by Crabtree’s advice, laid aside Lansbergius, whose tables he found erroneous, and his hypotheses inconsistent. He was pursuing his studies with great vigour and success, when he was cut off by a sudden death, Jan. 3, 1640-1.

, a very celebrated mathematician and astronomer, was born at the Hague April 14, 1629, and was son of Constantino Huygens, lord of Zuylichem, who had served three successive princes of Orange in the quality of secretary, and had spent his whole life in cultivating the mathematics not in the speculative way only, but in making them subservient to the uses of life., From his infancy our author applied himself to this study, and made a considerable progress in it, even at nine years of age, as well as in music, arithmetic, and geography; in all which he was instructed by his father, who in the mean time did not suffer him to neglect the belles lettres. At thirteen he was initiated in the study of mechanics; having discovered a wonderful curiosity in examining machines and other pieces of mechanism; and two years after had the assistance of a master in mathematics, under whom he made surprising progress. In 1645 he went to study law at Leyden, under Vinnius; yet did not attach himself so closely to that science, but that he found time to continue his mathematics under the professor Schooten. He left this university at the end of one year, and went to Breda, where an university had just been founded, and placed under the direction of his father; and here, for two or three years, he made the law his chief study. In 1649 he went to Holstein and Denmark, in the retinue of Henry count of Nassau; and was extremely desirous of going to Sweden to visit Des Cartes, who was then in that country with the queen Christina, but the count’s short stay in Denmark would not permit him. In 1651, he gave the world a specimen of his genius for mathematics, in a treatise entitled “Theoremata de quadratura Hyperboles, Ellipsis, & Circuli, ex dato portionum gravitatis centro” in which he shewed very evidently what might be expected from him afterwards.

, of Alexandria, a disciple of Isidorus, flourished under M. Aurelius, and Lucius Verus, in the second century. He has been supposed to be the author of a certain work called “Anaphoricus,” or a book of ascensions, which was written in opposition to the doctrines of some astronomer. It was published in Greek, with the Latin version of Mentelius, and in conjunction with the Optics of Heliodorus, at Paris, in 1680, 4to. Vossius, in his book “de Scientiis Mathematicis,” has erroneously supposed him to have lived at a much earlier period.

, the greatest astronomer perhaps that any age has produced, was born at Wiel in the dutchy of Wirtemberg, Dec. 27, 1571. His father, Henry Kepler, was descended from a family which had raised themselves under the emperors by their military services, and was himself an officer of rank in the army; but afterwards, experiencing ill fortune, was obliged to sell all he had, and support himself and his family by keeping a public-house. He died in 1590, and' left his son John without provision. His education had be^n therefore neglected, but, by the favour of his prince, he was enabled to enter upon his studies in philosophy at Tubingen, immediately upon his father’s death, and, two years after, pursued the mathematics in the same university, under the famous Michael Maestlinus, an astronomer of eminence, and of the Copernican school, but at this time Kepler informs us he had. no particular predilection for astronomy. His passion was rather for studies more fluttering to the ambition of a youthful mind; and when his prince selected him, in 1591, to fill the vacant astronomical chair, it was purely from deference to his authority, and the persuasions of Masstlinu, who had high expectations from his talents, that he reluctantly accepted of the office. He appears to have thought it unsuitable to his pretensions; and the state of astronomy was besides so low, uncertain, and in many respects visionary, that he had no hope of attaining to eminence in it. But what he undertook with reluctance, and as a temporary provision conferred on a dependant by his prince, soon engaged his ardour, and engrossed almost his whole attention. The first fruit? of his application to astronomical studies appeared in his “Mysterium Cosmographicum,” published about two years after his settlement in Gratz; and hasty and juvenile as this production was, it displayed so many marks of genius, and such indefatigable patience in the toil of calculation, that on presenting it to Tycho Brahe, it procured him the esteem of that illustrious astronomer, and even excited his anxiety for the proper direction of talents go uncommon. Accordingly, not contented with exhorting Kepler to prefer the road of observation to the more uncertain one of theory, Tycho added an invitation to live with him at Uraniburg, where his whole observations should be open to Kepler’s perusal, and those advantages provided for making others, which his situation at Gratz denied. This after some time was accepted. In 1597, Kepler entered into the married state, which at first created him great uneasiness, from a dispute which arose about his wife’s fortune; and, the year after, he was banished from Gratz on account of his religion, but afterwards recalled, and restored to his former dignity. However, the growing troubles and confusions of that place inclined him to think of a residence elsewhere; and he now determined to accept T. Brahe’s invitation, and accordingly left the university of Gratz, and removed into Bohemia with his family in 1600. In his journey he was seized with a quartan ague, which continued seven or eight months; and prevented his profiting by Tycho’s kindness, and, what was worse, some petty differences interrupted their connection. Kepler was offended at Tycho, for refusing some services to his family, which he had occasion for: he was also dissatisfied with his reserved ness; for, Tycho did not communicate to him all that he knew; and, as he died in 1601, he did not give Kepler time to be very useful to him, or to receive any considerable advantages from him. Before his death, however, he introduced him to the emperor Rodolphus at Prague (for, it was upon this condition that Kepler had consented to leave Gratz), who received him very kindly, and made him his mathematician, upon condition that he should serve Tycho as an arithmetician. From that time Kepler enjoyed the title of mathematician to the emperor all his life, and gained more and more reputation every year by his works. Rodolphus ordered him to finish the tables begun by Tycho, which were to be called the “Rodolphine Tables” and he applied himself very vigorously to this work but such difficulties arose in a short time, partly from the nature of it, and partly from the delay of the treasurers, that the tables were not finished and published till 1627. He complained, that, from 1602 and 1603, he. was looked upon by the treasurers with a very invidious eye; and when, in 1609, he had published a noble specimen o/ the work, and the emperor had given orders that, besides the expence of the edition, he should immediately be paid the arrears of his pension, which, he said, amounted to 2000 crowns, and likewise 2000 more; yet, that it was not till two years after, that the generous orders of Rodolphus, in his favour, were put in execution. He met with no less discouragement from the financiers under the emperoc Matthias, than under Rodolphus; and therefore, after struggling with poverty for ten years at Prague, began to think of quitting his quarters again. He was then fixed at Lints by the emperor Matthias, who appointed him a salary from the states of Upper Austria, which was paid for sixteen years. In 1613 he went to the assembly at Ratisbon, to assist in the reformation of the calendar; but returned to Lints, where he continued to 1626. In November of that year, he went to Ulm, in order to publish the “Rodolphine Tables;” and afterwards, in 1629, with the emperor’s leave, settled at Sagan in Silesia, where he published the second part of his “Ephemerides;” fot the first had been published at Lints in 1617. In 1630, he went to Ratisbon, to solicit the payment of the arrears of his pension; but, being seized with a fever, which, it is said, was brought upon him by too hard riding, he died there in November, in his 59th year.

, the first of a family of astronomers, of considerable note, was born at Guben, in Lower Lusatia, in 1640, and educated at Leipsic, where he acquired reputation by the almanacs which he published. In 1692 he married Mary Margaret Winckehnan, who rendered him much useful assistance by making astronomical observations for the construction of his Ephemerides. In 1701, on the establishment of the academy of sciences at Berlin by Frederic I. king of Prussia, that prince appointed him a member of the society, and astronomer in ordinary, with an honourable pension for his support. He died at Berlin in 1710, at the age of seventy-one years. He had been in the habit of corresponding with all the learned societies of Europe, and published a variety of astronomical treatises, which are in considerable estimation. His wife, Mary Margaret, the daughter of a Lutheran clergyman at Panitzsh, a village near Leipsic, where she was born in 1670, was early noticed for her astronomical talents, and in 1702, some years after her marriage, she first saw a comet, upon, which M. Kirch published his observations. In 1707 she discovered a peculiar aurora borealis, mentioned in the Memoirs of the academy of sciences at Paris for 1716. These exertions of her genius procured her the esteem of the learned at Berlin, notwithstanding which she was in very low circumstances when her husband died. She contrived to maintain herself and educate her children, by constructing almanacs; and, in 1711, she published a dissertation entitled “Preparations for observing the grand Conjunctions of Saturn, Jupiter, &c.” Soon after this she found a patron in the baron de Throsick, and on his death two years afterwards, removed to Dantzic, when Peter the Great wished to engage her to settle in his empire. She preferred her native country, and, in 1716, accompanied her son to Berlin, where she was appointed astronomer to the academy of sciences in that city, and died there in 1720. Their son Christian Fkederic, born at Guben in 1694, who also discovered an early and very strong bias for scientific pursuits, commenced his studies at Berlin, and afterwards continued them at Halle, whence he made excursions for improvement to Nuremberg, Leipsic, and Prussia. He was employed a considerable time in the observatory at Dantzic, and during his residence here, the czar, Peter the Great, offered him an establishment at Moscow; but his attachment to his mother, who was averse from leaving Germany, led him to decline it. In 1717 he was made member of the academy of sciences at Berlin, and in 1723 he was chosen a corresponding member of the royal academy of sciences at Paris, and he shewed himself worthy of that distinction by the frequent valuable contributions which he transmitted to them during the remainder of his life. He died in 1740, in the forty-sixth year of his age. He published several works connected with astronomy, which were in considerable reputation at the period in which he flourished.

, a celebrated traveller, was born in 1674, at Dorflas, in the principality of Baireuth, of which place his father was a judge, and afterwards a receiver of taxes. His early years were passed in poverty, until, in 1696, he was received into the* house of Eimart, an astronomer, under whose directions he made considerable progress in the sciences. He entered the university of Halle in 1700, and afterwards gave a course of lectures in mathematics and philosophy. He was introduced to baron von Krosie, privy counsellor to his Prussian majesty, to whom he became secretary, and whom he accompanied in his travels; and a proposal being made to him to go to the Cape of Good Hope, he gladly embraced the opportunity. Here he remained ten years, making observations on the country and the people, till he was afflicted with blindness, from which, however, on his return to Europe, he so far recovered as to be able to read with the assistance of glasses. In 1716 he inserted in the Acta Eruditorum a treatise “De aquis Capitis Bonse Spei.” This work introduced him into farther notice, and he was appointed rector of the school of Neustadt, where he died in 1726. His chief publication was “A Description of the Cape of Good Hope,” in folio, with twenty-four plates. This work was translated into Dutch in 1727; and at London, into English, in 1731, by Mr. Medley, who lopped o.'Fsome of its redundancies. It was afterwards abridged, and published in French in three vols. 12mo. The first attack on the veracity of tliis work was made by the abbe“de la Caille, who, in his Journal of the voyage to the Cape, said that he took Kolben’s description with him, but found it full of inaccuracies and falsehoods, and more resembling a series of fables than an authentic narrative. It has been also said that Kolben having passed the whole of his time with his bottle and his pipe, was perplexed to find that he had nothing to show in Europe, as the first fruits of his supposed labours, and therefore engaged some inhabitants of the Cape to draw up for him that description of the colony which he imposed upon the public as his own. Forstcr, on the other hand, in his” Voyage round the World," ascribes to La Caille certain interested motives in thus decrying Kolben' s work, and says it would be easy to refute almost every criticism which the abbe* has passed on that intelligent and entertaining voyager. These different opinions might perplex us, if more recent travellers had not rendered us independent both of Kolben and La Cailie.

, a very celebrated French astronomer, was born at Bourg, in the department of l'Ain, July 11, 1732. His father, who was possessed of property, intended him for the bar, and sent him to Paris to study the law, to which, for some time, he applied with so much assiduity, as to answer the most sanguine expectations of his friends, when the sight of an observatory awakened in him a propensity, which deranged the projects of his parents, and became the ruling passion of his life. He put himself under the instructions of Le Monnier, one of the then most celebrated astronomers of France, and profited so much by the lessons of his able instructor, as to afford him the highest degree of satisfaction, who, on his part, conceived for the young man a truly paternal affection, and was determined to promote his interests. An opportunity soon offered; the great astronomer Lecaille was preparing to set out for the Cape of Good Hope, in order to determine the parallax of the moon, and its distance from the earth. To accomplish this purpose, it was necessary he should be seconded by an observer placed under the same meridian, and at the greatest distance that could be conveniently chosen on the globe. Berlin was fixed on, and Le Monnier signified his intention of undertaking the business himself, but the mo.­ment when he appeared ready to depart, he had the credit to get his pupil appointed in his stead. Frederic, to whom Maupertuis had explained the delicacy and difficulty of the enterprize, could not forbear shewing some astonishment when the youthful astronomer was presented to him; “However,” said he, “the Academy of Sciences has appointed you, and you will justify their choice.” From that moment his age, being only eighteen, was an additional recommendation; he was admitted at court, welcomed by the academy, and became intimate with the most distinguished persons at Berlin. On his return, the account which he gave of his mission procured him free access to the Academy of Sciences, and its transactions were enriched every year by important communications from the young astronomer. The active part which he took in the labours of the academy, was not confined to the astronomical science: we have from his pen, a description of seven arts, as different from each other, as they are remote from the objects of his habitual meditations. He published the French edition of Dr. Halley’s tables, and the history of the comet of 1759, and he furnished Clairault with immense calculations for the theory of that famous comet. Being charged in 1760 with the compilation of the “Connoissance des Temps,” he entirely changed the form of that work, and of this collection he published thirty-two volumes, viz. from 1775 to 1807.

, an eminent mathematician and astronomer, was born at Muhlhausen, in the Sundgaw, a town in alliance with the Swiss cantons, Aug. 29th, 1728. His father was a poor tradesman, who, intending to bring him up to his own business, sent him to a public school, where he was taught the rudiments of learning, at the expence of the corporation, till he was twelve years old. Here he distinguished himself among his school-fellows, and some attempts were made to provide him with the means of studying theology as a profession, but for want of encouragement, he was under the necessity of learning his father’s trade. In this laborious occupation, however, he continued to devote a considerable part of the night to the prosecution of his studies; and to furnish himself with candles, he sold for half-pence or farthings small drawings which he delineated while employed in rocking his infant sister in a cradle. He met with an old book on the mathematics which gave him inexpressible pleasure, and which proved that he had a genius for scientific pursuits. Seeing the turn which the young man had for knowledge, several learned men afforded him assistance and advice; and they had the pleasure of finding him improve, under their patronage, with a rapidity beyond their most sanguine expectations. He was now taken from the drudgery of the shop-board, and M. Iselin, of Basil, engaged him as his amanuensis, a situation which afforded him an opportunity of making further progress in the belles-lettres, as well as philosophy and mathematics. In 1748, his patron recommended him to baron Salis, president of the Swiss confederacy, to become tutor to his children, in which office he gladly engaged. His talents as a philosopher and mechanician began to display themselves in his inventions and compositions. After living eight years at Coire, he repaired, in 1756, with his pupils, to the university of Gottingen, where he was nominated a corresponding member of the scientific society in that place, and from thence he removed, in the following year, to Utrecht, where he continued twelve months. In 1758, he went with his pupils to Paris, where he acquired the esteem and friendship of D' Alembert and Messier; and from thence he travelled to Marseilles, and formed the plan of his work “On Perspective,” which he published in the following year at Zurich. In 1760 he published his “Photometry,” a master-piece of sagacity, which contains a vast quantity of information of the most curious and important nature. In the same year he was elected a member of the Electoral Bavarian Scientific Society. Lambert was author of many other pieces besides those which have been already mentioned: among these were his “Letters on the Construction of the Universe,” which were afterwards digested, translated, and published under the title of “The System of the World.” In 1764 he made an excursion to Berlin, and was introduced to Frederic II., who, sensible of his great services to science, gave directions to have him admitted a regular member of the academy; this appointment enabled him to devote himself wholly to the pursuit of his favourite studies. He enriched the transactions of several learned societies with his papers and treatises, some of which he published separately. He died Sept. 25th, 1777, when he was in the 50th year of his age. Most of his mathematical pieces were published in a collective form by himself in three volumes, in which almost every branch of mathematical science has been enriched with additions and improvements.

, a native of America, of a very enterprising turn, was born at Groton in Connecticut. Having lost his father in his infancy, he was taken undef the care of a relation, who sent him to a grammar-school, and he studied for some time at Dartmouth college, in New Hampshire. Here it appears to have been his intention to apply to theological studies, l>ut the friend who sent him to college being dead, he was obliged to quit it, and by means of a canoe of Ins own const ruction, he found his way to Hartford, and thence to New York, where he went on board ship as a common sailor, and in this capacity arrived at London in 1771. When at college, there were several young Indians there for their education, with whom he used to associate, and learned their manners and hearing of capt. Cook’s intentions to sail on his third voyage, Ledyard engaged himself with him in the situation of a corporal of marines and on his return from that memorable voyage, during which his curiosity was rather excited than gratified, feeling an anxious desire of penetrating from the north-western coast of America, which Cook had partly explored, to the eastern coast, with which he himself was perfectly familiar, he determined to traverse the vast continent from the Pacific to the Atlantic ocean. His first plan for the purpose was that of embarking in a vessel, which was then preparing to sail, on a voyage of commercial adventure, to Nootka sound, on the western coast of America; and with this view he expended in sea-stores the greatest part of the money with which he had been supplied by the liberality of sirJoseph Banks, who has eminently distinguished himself in this way on other occasions for the promotion of every kind of useful science. But this scheme was frustrated by the rapacity of a customhouse officer; and therefore Mr. Ledyard determined to travel over land to Kamtschatka, from whence the passage is extremely short to the opposite coast of America. Accordingly, with no more than ten guineas in his purse, which was all that he had left, he crossed the British channel to Ostend, towards the close of 1786, and by the way of Denmark and the Sound, proceeded to the capital of Sweden. As it was winter, he attempted to traverse the gulf of Bothnia on the ice, in order to reach Kamtschatka by the shortest course; but finding, when he came to the middle of the sea, that the water was not frozen, he returned to Stockholm, and taking his course northward, walked to the Arctic circle, and passing round the head of the gulf, descended on its eastern side to Petersburg, where he arrived in the beginning of March 1787. Here fae was noticed as a person of an extraordinary character; and though he had neither stockings nor shoes, nor means to provide himself with any, he received and accepted an, invitation to dine with the Portuguese ambassador. From him he obtained twenty guineas for a bill, which he took the liberty, without being previously authorized, to draw on sir Joseph Banks, concluding, from his well-known disposition, that he would not be unwilling to pay it. By the interest of the ambassador, as we may conceive to have been probably the case, he obtained permission to accompany a detachment of stores, winch the empress had ordered to be sent to Yakutz, for the use of Mr. Billings, an Englishman, at that time in her service. Thus accommodated, he left Petersburg on the 2 1st of May, and travelling eastward through Siberia, reached Irkutsk in August; and from thence he proceeded to Yakutz, where he was kindly received by Mr. Billings, whom he recollected on board captain Cook’s ship, in the situation of the astronomer’s servant, but who was now entrusted by the empress in accomplishing her schemes of discovery. He returned to Irkutsk, where he spent part of the winter; and in the spring proceeded to Oczakow, on the coast of the Kamtschatkan sea, intending, in the spring, to have passed over to that peninsula, and to have embarked on the eastern side in one of the Russian vessels that trade to the western shores of America; but, finding that the navigation was completely obstructed, he returned to Yakutz, in order to wait for the termination of the winter. But whilst he was amusing himself with these prospects, an express arrived, in January 1788, from the empress, and he was seized, for reasons that have not been explained, by two Russian soldiers, who conveyed him in a sledge through the deserts of Northern Tartary to Moscow, without his clothes, money, and papers. From Moscow he was removed to the city of Moialoff, in White Russia, and from thence to the town of Tolochin, on the frontiers of the Polish dominions. As his conductors parted with him, they informed him, that if he returned to Russia he would be hanged, but that if he chose to go back to England, they wished him a pleasant journey. Distressed by poverty, covered with rags, infested with the usual accompaniments of such clothing, harassed with continual hardships, exhausted by disease, without friends, without credit, unknown, and reduced to the most wretched state, he found his way to Konigsberg. In this hour of deep distress, he resolved once more to have recourse to his former benefactor, and fortunately found a person who was willing to take his draft for five guineas on the president of the royal society. With this assistance he arrived in England, and immediately waited on sir Joseph Banks. Sir Joseph, knowing his disposition, and conceiving, as we may well imagine, that he would be gratified by the information, told him, that he could recommend him, as he believed, to an adventure almost as perilous as that from which he had just returned; and then communicated to him the wishes of the Association for discovering the Inland Countries of Africa. Mr. Ledyard replied, that he had always determined to traverse the continent of Africa, as soon as he had explored the interior of North America, and with a letter of introduction by sir Joseph Banks, he waited on Henry Beaufoy, esq. an active member of the fore-mentioned association. Mr. Beaufoy spread before him a map of Africa, and tracing a line from Cairo to Sennar, and from thence westward in the latitude and supposed direction of the Niger, informed him that this was the route by which he was anxious that Africa might, if possible, be explored. Mr. Ledyard expressed great pleasure in the hope of being employed in this adventure. Being asked when he would set out? “To-morrow morning” was his answer. The committee of the society assigned to him, at his own desire, as an enterprise of obvious peril and of difficult success, the task of traversing from east to west, in the latitude attributed to the Niger, the widest part of the continent of Africa. On the 30th of June 1788, Mr. Ledyard left London; and after a journey of thirty-six days, seven of which were consumed at Paris, and two at Marseilles, he arrived in the city of Alexandria. On die 14th of August, at midnight, he left Alexandria, and sailing up the Nile, arrived at Cairo on the 19th. From Cairo he communicated to the committee of the society all the information which he was able to collect during his stay there: and they were thus sufficiently apprized of the ardent spirit of inquiry, the unwearied attention, the persevering research, and the laborious, indefatigable, anxious zeal, with which he pursued the object of his mission. The next dispatch which they were led to expect, was to be dated at Sennar; the terms of his passage had been settied, and the day of his departure was appointed. The committee, however, after having expected with impatience the description of his journey, received with great concern and grievous disappointment, by letters from Egypt, the melancholy tidings of his death. By a bilious complaint, occasioned probably by vexatious delay at Cairo, and by too free an use of the acid of vitriol and tartar emetic, the termination of his life was hastened. He was decently interred in the neighbourhood of such of the English as had ended their days in the capital of Egypt,

, a celebrated astronomer in the sixteenth century, was born in Bohemia, and was appointed mathematician to Otho Henry, elector palatine. He acquired a high reputation by his astronomical productions, of which the principal were, “Ephemerides ab anno 1556 ad ann. 1606;” “Expedita Ratio constituendi Tin-mat is coelestis” “Loca stellarum fixarum ab anno Dom. 1549 usque in ann. 2029” and “De Eclipsibus Liber.” Tycho Brahe paid him a visit in 1569, when they had several conversations on their favourite subjects. Notwithstanding the great learning of Leowitz, he was weak enough to become the dupe of judicial astrology. He died in Swabia 1574. He had predicted that the world would come to an end in 1584; and of this prophecy many priests and preachers took advantage as the important period approached, and enriched themselves at the expence of the fears of their people.

, brother of the preceding, and an astronomer, promoted the interests of science, by some very hazardous journeys and voyages. In 1726 he went to Russia with his brother Joseph, who had been appointed astronomer to the academy of sciences at Petersburg. Lewis, at this time, made excursions beyond the utmost boundaries of the immense Russian empire. He took several journeys to the coasts of the Icy sea, to Lapland, and the government of Archangel, to determine the situation of the principal places by astronomical observations. He afterwards traversed a great part of Siberia, with M. Muller and M. Gmelin, professors of the academy at Petersburg. In 1741 he proceeded alone to Kamtschatka, and thence to Cape Beering, to examine the unknown northern coasts of America, and the seas between them and the Atlantic continent. He died in the same year. On account of his great merit he obtained a seat in the academy of sciences, and was the author of some papers in the “Memoirs” of that learned body, and of the academy of sciences at Petersburg.

, younger brother of the preceding, was born at Paris April 4, 1688, and at first educated under his paternal roof. He then pursued his studies at the Mazarine-college, where the eclipse of the sun in 1706 seems to have directed his attention to astronomy, for which he soon displayed so much genius, as to be admitted into the academy of sciences, to the memoirs of which he contributed many valuable papers. In 1715 he calculated the tables of the moon according to the theory of sir Isaac Newton. He also, in the course of his pursuits, made many observations on the spots of the sun, and from them formed a theory to determine the sun’s rotation on his axis. In 1720 he delivered a proposal to the academy for ascertaining in France the figure of the earth, and some years afterwards this was carried into execution. In 1724 he paid a visit to England, where he became acquainted with Newton and Halley, who shewed him every mark of respect, and Halley in particular highly gratified him by a present of a copy of his astronomical tables of the sun, moon, and planets, which he had printed in 1719, but which were not published for many years after. In. 1726 he was appointed astronomer royal in the imperial academy of sciences at Petersburg, where for twenty- one years he resided in the observatory-house built by Peter the Great, incessantly occupied in the improvement of astronomy and geography. During this period he published “Memoirs illustrative of the History of Astronomy,” 2 vols. 4to; and an atlas of Russia, first published in the Russian language, and afterwards in Latin. He constructed also a thermometer, differently graduated from those in use, the degrees beginning at the heat of boiling water, and thence increasing to 150, which was the freezing point. In 1747, after much ill-treatment on the part of the Russian government, he obtained his dismission, and arrived in Paris in September of the same year. He was then appointed professor of the mathematics at the college royal, in which situation he lived to render the greatest service to the interests of science, by training up some learned pupils, among whom was the celebrated M. de la Lande. In 1743, his pupil, M. Monnier, took a voyage to Scotland to observe an annular eclipse of the sun, and on this subject De Lisle published a large advertisement, which was reckoned a complete treatise on annular eclipses. He afterwards entered more fully on the consideration of the theory of eclipses, and he communicated a part of his researches on the subject to the academy in 1749. He was so expert in calculations, that he made many founded on the observations of Greenwich, Berlin, Scotland, and Sweden. In 1750 and 1753 he published “New charts of the Discoveries of admiral de Fonte, or Fuente, made in 1640, and those of other navigators, Spanish, Portuguese, English, Dutch, French, and Russian, in the Northern seas, with, explications.” In 1753 appeared his map of the world, in which he represented the effect of the parallaxes of Mercury in different countries, in order to point out the proper places for making such observations on the then expected transit, as should furnish a method of determining the distance of the sun, in a manner similar to that applied by Halley to the transit of Venus. Another work of his, published in the Transactions of the Academy, was on the comet of 1758, which was visible several months; but he was principally attentive to the one predicted by Di% Halley, forty years before, which was first seen in January 1759, He gave an account of his observations on that comet irr the first volume of the “Mercure,” for July of that year. He was afterwards assiduously engaged on the transit of Venus, expected in 1761, in order to correct the error of Halley, and thus prevent persons from undertaking long voyages unnecessarily for the sake of observing it. He had, some years previously to this, been appointed astronomical geographer to the marine, and his business was to collect and arrange the plans and journals of naval captains, and to extract from them whatever might be found beneficial to the king’s service in this department. His majesty now purchased, with a pension- for life, all M. de Lisle’s rich astronomical and geographical collections, which were added to the Mss. in the depot. In 1758, JDeginning to decline, he withdrew as much as he could from public life, leaving the care of his observations to M. Messier, while M. de la Lamle was appointed his coadjutor at the college royal. He went to reside at the abbey of St. Genevieve, where he spent his time partly in devotional exercises, and partly in study, devoting the greatest part of his income to- acts of benevolence and charity. He died on the 11th of July 1768, in the eighty-first year of his age. As a man of science his merits are very great, and in private life he was distinguished by unaffected piety, pure morals, undeviating integrity, and most amiable manners.

, an English divine and astronomer, was born about 1680, and was educated at Pembroke hall, Cambridge, of which he was A. B. in 1700, A.M. 1704, and S. T. P. in 1728. In 1733 he was elected master of Pembroke hall, and in 1749 Lowndes’s professor of astronomy. He is chiefly known as an author by a “Treatise on Astronomy,” in two volumes 4to; the first of which was published in 1742, and the second in 1764. He was the inventor of a curious astronomical machine, erected in a room at Pembroke hail, of which he has himself given the following description: “I have, in a room lately built in Pembroke hall, erected a sphere of 18 feet diameter, wherein above thirty persons may sit conveniently; the entrance into it is over the south pole by six steps; the frame of the sphere consists of a number of iron meridians, not complete semi-circles, the northern ends of which are screwed to a large plate of brass, with a hole in the centre of it; through this hole, from a beam in the cieling, comes the north pole, a round iron rod, about three inches long, and supports the upper parts of the sphere to its proper elvation for the latitude of Cambridge; the lower part of the sphere, so much of it as is invisible in England, is cut off; and the lower or southern ends of the meridians, or truncated semi-circles, terminate on, and are screwed down to, a strong circle of oak, of about thirteen feet diameter, which, when the sphere is put into motion, runs upon large rollers of lignum vitae, in the manner that the tops of some wind-mills are made to turn round. Upon the iron meridians is fixed a zodiac of tin painted blue, whereon the ecliptic and heliocentric orbits of the planets are drawn, and the constellations and stars traced; the great and little Bear and Draco are already painted in their places round the north pole; the rest of the constellations are proposed to follow; the whole is turned with a small winch, with as little labour as it takes to wind up a jack, though the weight of the iron, tin^ and wooden circle, is about a thousand pounds. When it is made use of, a planetarium will be placed in the middle thereof. The whole, with the floor, is well-supported by a frame of large timber.” Thus far Dr. Long, before this curious piece of mechanism was perfected. Since the above was written, the sphere has been completely finished; all the constellations and stars of the northern hemisphere, visible at Cambridge, are painted in their proper places upon plates of iron joined together, which form one concave surface.

, an eminent astronomer, was born at Longomontum, a town in Denmark, whence he took his name, in 1562. Vossius, by mistake, calls him Christopher. He was the son of Severinus, a poor labourer, and was obliged to divide his time between following the plow and attending to the lessons which the minister of the parish gave him, by which he profited so much as to acquire considerable knowledge, especially in the mathematics. At length, when he was fifteen, he stole from his family, and went to Wiburg, where there was a college, in which he spent eleven years, supporting himself by his talents: and on his removing thence to Copenhagen, the professors of this university soon conceived a high esteem for him, and recommended him to Tycho Brahe, who received him very kindly. He lived eight years with this eminent astronomer, and assisted him so much in his observations and calculations, that Tycho conceived a very particular affection for him, and having left his native country to settle in Germany, he was desirous of having the company of Longomontanus, who accordingly attended him. Afterwards being, in 1600, desirous of a professor’s chair in Denmark, Tycho generously consented to give up his assistant and friend, with the highest testimonies of his merit, and supplied him plentifully with money for his journey. On his return to Denmark, he deviated from his road, in order to view the places whence Copernicus had made his astronomical observations; and passed so much time in this journey, that it was not till 1605 that he was nominated to the professorship of mathematics in the university of Copenhagen. In this situation he continued till his death, in 1647, when he was eighty-five years old. He married, and had children; but the whole of his family died before him. He was the author of several works, in mathematics and astronomy. His “Astronomia Danica,” first printed in 1611, 4to, and afterwards at Amsterdam, 1640, in folio, is the most distinguished. He amused himself with endeavouring to square the circle, and pretended that he had made the discovery of it; but our countryman Dr. John Pell attacked him warmly on the subject, and proved that he was mistaken. It is remarkable, that, obscure as his village and father might be, he dignified and perpetuated both; for he took his name from his village, and, in the title-page of his works, wrote himself “Christianus Longomontanus Severini films.”

He was, says Warton, who of all our modern critics has considered him with most attention, a monk of the Benedictine abbey of Bury in Suffolk. After a short education at Oxford, he travelled into France and Italy; and returned a complete master of the language and the literature of both countries. He chiefly studied the Italian and French poets, particularly Dante, Boccaccio, and Alain Chartier; and became so distinguished a proficient in polite learning, that he opened a school in his monastery, for teaching the sons of the nobility the arts of versification, and the elegancies of composition. Yet, although philology was his object, he was not unfamiliar with the fashionable philosophy: he was not only a poet and a rhetorician, but a geometrician, an astronomer, a theologist, and a disputant. Mr. Warton is of opinion that he made considerable additions to those amplifications of our language, in which Chaucer, Gower, and Hoccleve, led the way; and that be is the first of our writers whose style is clothed wjth that perspicuity in which the English phraseology appears at this day to an English reader.

, son of a Polish Jew, who was a silversmith, and teacher of Hebrew at Cambridge, was born there, in 1739. He displayed wonderful talents as a young man; and shewed very early a great inclination to learning, particularly mathematics; but though Dr. Smith, then master of Trinity-college, offered to put him to school at his own expence, he would go only for a day or two, saying, “he could learn more by himself in an hour than in a day with his master.” He began the study of botany in. 1755, which he continued to his death; and could remember, not only the Linniean names of almost all the English plants, but even the synonyma of the old botanists, which form a strange and barbarous farrago of great bulk; and had collected large materials for a “Flora Cantabrigiensis,” describing fully every part of each plant from the life, without being obliged to consult, or being liable to be misled by, former authors. In 1758 he obtained much celebrity by publishing a treatise “on Fluxions,” dedicated to his patron, Dr. Smith; and in 1763 a work entitled “Fasciculus plantaruui circa Cantabrigiam nascentium, quae post Raium observatae fuere,” 8vo. Mr. Banks (now sir Joseph Banks, bart. and president of the royal society), whom he first instructed in this science, sent for him to Oxford, about 1762 or 1763, to read lectures; which he did with great applause, to at least sixty pupils; but could not be induced to make a long absence from Cambridge. He had a salary of a hundred pounds per annum for calculating the “Nautical Almanack,” and frequently received presents from the board of longitude for his inventions. He could read Latin and French with ease; but wrote the former ill; had studied the English history, and could quote whole passages from the Monkish writers verbatim. He was appointed by the board of longitude to go with captain Phipps (afterwards lord Mulgrave) to the North pote in 1773, and made the astronomical and other mathematical calculations, printed in the account of that voyage. After his return he married and settled in London, where, on May 1, 1775, he died of the measles. He was then engaged in publishing a complete edition of all the works of Dr. Halley. His “Calculations in Spherical Trigonometry abridged,” were printed in “Philosophical Transactions,*' vol. LXI. art. 46. After his death his name appeWed in the title-page of” A Geographical Dictionary,“of which the astronomical parts were said to be” taken from the papers of the late Mr. Israel Lyons, of Cambridge, author of several valuable mathematical productions, and astronomer in lord Mnlgrave’s voyage to the Northern hemisphere.“It remains to be noticed, that a work entitled” The Scholar’s Instructor, or Hebrew Grammar, by Israel Lyons, Teacher of the Hebrew Tongue in the University of Cambridge: the second edition, with many Additions and Emendations which the Author has found necessary in his long course of teaching Hebrew,“Cambridge, 1757, 8vo, was the production of his father; as was a treatise printed at the Cambridge press, under the title of” Observations and Enquiries relating to various parts of Scripture History, 1761," published by subscription at two shillings and six-pence. He died in August 1770, and was buried, agreeably to his own desire, although contrary to the Jewish principles, in Great St. Mary’s Church-yard, Cambridge. He was on this occasion carried through the church, and his daughter Judith read some form of interment-service over his grave. He had resided near forty years at Cambridge.

, a celebrated astronomer of Germany, whose name deserves to be preserved, was born about 1542, in the dutchy of Wirtemberg, and spent his youth in Italy, where he made a public speech in favour of Copernicus, which served to wean Galileo from Aristotle and Ptolemy, to whom he had been hitherto entirely devoted. He returned afterwards to Germany, and became professor of mathematics at Tubingen; where he had among his scholars the great Kepler. Tycho Brahe, though he did not assent to Maestlin, has yet allowed him to be an extraordinary person, and well acquainted with the science of astronomy. Kepler has praised several ingenious inventions of Mæstlin’s, in his “Astronomia Optica.” He died in 1590, after having published many works in mathematics and astronomy, among which were his treatises “De Stella nova Cassiopeia;” “Ephemerides,” according to the Prutenic Tables, which were first published by Erasmus Reinoldus in 1551. He published Iikew4se “Thesis de Eclipsibus” and an “Epitome of Astronomy,” &c.

, a celebrated astronomer and mathematician, was born at Bologna in 1674, and soon displayed a genius above his age. He wrote ingenious verses while he was but a child, and while very young formed in his father’s house an academy of youth of his own age, which in time became the Academy of Sciences, or the Institute, there. He was appointed professor of mathematics at Bologna in 1698, and superintendant of the waters there in 1704. The same year he was placed at the head of the college of Montalto, founded at Bologna for young men intended for the church. In 1711 he obtained the office of astronomer to the institute of Bologna. He became member of the Academy of Sciences of Paris in 1726, and of the Royal Society of London in 1729; and died on the 15th of February 1739. His works are: 1. “Ephemerides Motuum Coelestium ab anno 17 15 ad annum 1750;” 4 vols. 4to. The first volume is an excellent introduction to astronomy; and the other three contain numerous calculations. His two sisters were greatly assisting to him in composing this work. 2. “De Transitu Mercurii per Solem, anno 1723,” Bologna, 1724, 4to. 3. “De annuls Inerrantium Stellarum aberrationibus,” Bologna, 1729, in 4to; besides a number of papers in the Memoirs of the Academy of Sciences, and in other places, which are enumerated by Fabroni. The best edition of his Poems, which are still in repute, is that by Bodoni, in 1793, 8vo, with a life of the author.

, a learned astronomer and mathematician, was born in 1665 at Perinaldo in the county of Nice, a place already honoured by the birth of his maternal uncle, the celebrated Cassini. Having made a considerable progress in mathematics, at the age of twentytwo his uncle, who had been a long time settled in France, invited him there, that he might himself cultivate the promising genius of his nephew. Maraldi no sooner applied himself to the contemplation of the heavens, than he conceived the design of forming a catalogue of the fixed stars, the foundation of the whole astronomical edifice. In consequence of this design, he applied himself to observe them with the most constant attention; and he became by this means so intimate with them, that on being shown any one of them, however small, he could immediately tell what constellation it belonged to, and its place in that constellation. He has been known to discover those small comets, which astronomers often take for the stars of the constellation in which they are seen, for want of knowing precisely what stars the constellation consists f, when others, on the spot, and with eyes directed equally to the same part of the heavens, could not for a long time see any thing of them.

, an eminent astronomer and mathematician, the son of Edmund Maskelyne, esq. of Purton, in Wiltshire, was born at London in 1732, and educated at Westminster school, where he made a distinguished progress in classical learning. Before he left school his studies appear to have been determined to astronomy by his accidentally seeing the memorable solar eclipse of 1748, exhibited through a large telescope in a camera obscura. From this period he applied himself with ardour to astronomy and optics, and as a necessary preparation, turned his attention to geometry and algebra, the elements of which he learned in a few months without the help of a master. In 1749 he entered of Catherine hall, Cambridge, but soon after removed to Trinity college, where he pursued his favourite studies with increased success; and on taking his degree of B. A. in 1754, received distinguished honours from the university. He took his degrees of A.M. in 1757, B. D. in 1768, and D. D. in 1777. Being admitted into holy orders he officiated for some time as curate of Barnet; and in 1756 became a fellow of his college.

In 1764, the office of astronomer-royal becoming vacant by the death of Mr. Bliss, Dr. Maskelyne’s celebrity immediately pointed him out as the most competent person to fill the situation, and to carry into effect the purpose for which the royal observatory haid been established, that o preparing tables for finding the longitude at sea. Accordingly, his appointment to it, which was announced in the London Gazette, Feb 16, 1765, gave universal satisfaction. During the long period of Dr. Maskelyne’s official services, his time may be considered as chiefly occupied either at the observatory, the board of longitude, or the royal society; and his biography, therefore, like that of most other scientific men, consists chiefly in a history of his labours. ­Soon after his appointment he laid belor^he board of longitude the plan of an annual publication, to be entitled the “Nautical Almanac, and Astronomical Ephemeris.” The first volume was for 1767 and it has been continued under his direction, up to the present time, making in the whole fifty volumes a lasting monument of labour and profound learning. It is universally allowed to be the most useful work on practical astronomy ever published. In such high estimation has it been held by foreign astronomers, that they have generally and implicitly adopted its computations, and acknowledged its superior accuracy. M. Lalande, in giving an account of similar publications, says, “Le Nautical Almanac de Londres est l‘Ephemeride la plus parfaite qu’il y aitjarnais eu.”

Another important and laborious duty that devolved on him in consequence of his office was, to examine the pretensions of the various candidates who claimed the parliamentary rewards for new or improved methods of finding the longitude. His appointment took place at a period peculiarly interesting in the history of astronomy. His success in introducing and promoting the lunar observations greatly excited the public attention to the subject of the longitude, which was rendered still more interesting by the great rewards held out by parliament for further improvements in the problem, whether by astronomical or mechanical methods. These offers, united with the powerful motives of honour and emulation, called forth, flaring several years, many extraordinary efforts of genius, and produced useful inventions both in arts and sciences, and particularly in the construction of time-keepers. The parliamentary offers likewise encouraged numerous candidates of very slight pretensions, and even visionaries, whose applications became very troublesome. The claims of all were referred by the board of longitude to the astronomer royal, by whom scientific plans were examined, and the rates of chronometers ascertained. Thus by his office he was constituted arbiter of the fame and fortune of a great number of anxious projectors; and it is easy to conceive how arduous as well as unpleasant such a duty must have been. It was not indeed to be expected that the sanguine hopes and self-love of such a variety of candidates could be gratified, with justice to the high trust and confidence thus 1 reposed in him; and hence complaints were frequently heard, and pamphlets published, expressive of discontent and disappointment. Appeals even were made to parliament; but whatever difference of opinion might have then existed, time and experience have since fully proved the truth and impartiality of Dr. Maskelyne’s decisions.

In the history of science, few persons can be mentioned who have contributed more essentially to the diffusion of astronomical knowledge than Dr. Maskelyne; and perhaps no man has been so successful in promoting practical astronomy, both by land and sea. During his time private observatories became very general, though scarcely known before; nor could such be made useful without his “Nautical Almanac,” and other tables, except by men of great science, and by very laborious calculations. Beside the assistance thus derived from his publications, he was always ready to give advice concerning any plans that were likely to promote the science. Among the observatories that were erected through his encouragement, may be mentioned that of the late Alexander Aubert, esq. whose excellent collection of instruments has been rarely equalled, even in national institutions; and several other instances might be adduced of observatories which were erected by the advice or direction of the astronomer royal. He was besides a great improver of instruments, and the inventor of some, among which may be noticed the prismatic micrometer; but though profoundly skilled in optics, and ingenious in mechanical contrivances, he always paid great deference to the opinions of opticians, and other practical mechanists. His plans were mostly directed to substantial objects, while a steady perseverance gave an efficiency to all his undertakings: and notwithstanding his profound knowledge of physical astronomy, his attention was chiefly directed to reduce the scientific theories of his predecessors to the practical purposes of life. In this he was eminently successful, particularly in his labours for the longitude, by which he essentially contributed to the advancement of navigation, the prosperity of commerce, and the wealth, honour, and power of his country.

, a very able French mathematician and astronomer, was born at Laon in 17 44, where his father was an architect, and at one time a man of considerable property. At an early age he discovered a strong inclination for mathematical pursuits, and while he was under the instruction of his tutors, corresponded with Lalande, whom he was desirous of assisting in his labours. In 1772, Mechain was invited to Paris, where he was employed at the depot of the marine, and assisted M. Darquier in correcting his observations. Here his merit brought him acquainted with M. Doisy, director of the depot, who gave him a more advantageous situation at Versailles. At this place he diligently observed the heavens, and, in 1774, sent to the Royal Academy of Sciences “A Memoir relative to an Eclipse of Aldebaran,” observed by him on the 15th of April. He calculated the orbit of the comet of 1774, and discovered that of 1781. In 1782, he gained the prize of the academy on the subject of the comet of 1661, the return of which was eagerly expected in 1790; and in the same year he was admitted a member of the academy, and soon selected for the superintendance of the Connoissance des Tems. In 1790, M. Mechain discoveredhis eighth comet, and communicated to the academy his observations on it, together with his calculations of its orbit. In 1792 he undertook, conjointly with M. Delambre, the labour of measuring the degrees of the meridian, for the purpose of more accurately determining the magnitude of the earth and the length of a metre. In the month of June 1792, M. Mechain set out to measure the triangles between Perpignan and Barcelona; and notwithstanding that the war occasioned a temporary suspension of his labours, he was enabled to resume and complete them during the following year. He died on the 20th of September 1805, at Castellon de la Plana, in the sixty-second year of his age. Lalande deplores his loss as that of not only one of the best French astronomers, but one of the most laborious, the most courageous, and the most robust. His last observations and calculations of the eclipse of the sun on the llth of February, are inserted in the Connoissance des Tems for the year 15; and he also published a great many in the Ephemerides of M. Bode, of Berlin, which he preferred to a former work after Lalande became its editor. A more extensive memoir of his labours may be seen in Baron von Zach’s Journal for July 1800, and Lalande’s History of Astronomy for 1804.

, an eminent mathematician and astronomer, whose name in High-Dutch was Kauffman, was born about 1640, at Holstein in Denmark. From his works we learn, that he had an early and liberal education, suitable to his distinguished genius, by which he was enabled to extend his researches into the mathematical sciences, and to make very considerable improvements: for it appears from his writings, as well as from the character given of him by other mathematicians, that his talent rather lay in improving, and adapting any discoveries and improvements to use, than invention. However, his genius for the mathematical sciences was very conspicuous, and introduced him to public regard and esteem in his own country, and facilitated a correspondence with such as were eminent in those sciences, in Denmark, Italy, and England, In consequence, some of his correspondents gave him an invitation to this country, which he accepted; and he afterwards continued in England till hi death. In 1666 he was admitted F. R. S. and gave frequent proofs of his close application to study, as well as of his eminent abilities in improving some branch or other of the sciences. But he is charged sometimes with borrowing the inventions of others, and adopting them as his own, and it appeared upon some occasions that he was not of an over-liberal mind in scientific communications. Thus, it had some time before him been observed, that there was an analogy between a scale of logarithmic tangents and Wright’s protraction of the nautical meridian line, which consisted of the sums of the secants; though it does not appear by whom this analogy was first discovered. It appears, however, to have been first published, and introduced into the practice of navigation, by Henry Bond, who mentions this property in an edition of Norwood’s Epitome of Navigation, printed about 1645; and he again treats of it more fully in an edition of Gunter’s works, printed in 1653, where he teaches, from this property, to resolve all the cases of Mercator’s sailing by the logarithmic tangents, independent of the table of meridional parts. This analogy had only been found to be nearly true by trials, but not demonstrated to be a mathematical property. Such demonstration seems to have been first discovered by Mercator, who, desirous of making the most advantage of this and another concealed invention of his in navigation, by a paper in the Philosophical Transactions for June 4, 1666, invites the public to enter into a wager with him on his ability to prove the truth or falsehood of the supposed analogy. This mercenary proposal it seems was not taken up by any one; and Mercator reserved his demonstration. Our author, however, distinguished himself by many valuable pieces on philosophical and mathematical subjects. His first attempt was, to reduce astrology to rational principles, which proved a vain attempt. But his writings of more particular note, are as follow: 1. “Cosmographia, sive Descriptio Cceli & Terrse in Circulos, qua fundamentum sterniter sequentibus ordine Trigonometric Sphericorum Logarithmicse, &c. a” Nicolao Hauffman Holsato,“Dantzic, 1651, 12mo. 2.” Rationes Mathematics subductse anno 1653,“Copenhagen, 4to. 3.” De Emendatione annua Diatribae duae, quibus exponuntur & demonstrantur Cycli Soiis & Lunce,“&c. 4to. 4.” Hypothesis Astronomica nova, et Consensus ejus cum Observationibus,“Lond. 1664, folio. 5.” Logarithmotechnia, sive Method us construendi Logarithmos nova, accurata, et facilis; scripto antehac communicata anno sc. 1667 nonis Augusti; cui nunc accedit, Vera Quadratura Hyperbolae, & inventio summae Logaritbmorum. Auctore Nicolao Mercatore Holsato e Societate Regia. Huic etiam jungitur Michaelis Angeli Riccii Exercitatio Geometrica de Maximis et Minimis, hie ob argument! praestantiam & exemplarium raritatem recusa,“Lond. 1668, 4to. 6.” Institutionum Astronomicarum libri duo, de Motu Astrorum communi & proprio, secundum hypotheses veterum & recentiorum praecipuas deque Hypotheseon ex observatis constructione, cum tabulis Tychonianis, Solaribus, Lunaribus, Lunae-solaribus, & Rudolphinis Solis, Fixarum &*quinque Errantium, earumque usu prajceptis et exemplis commonstrato. Quibus accedit Appendix de iis, quae uovissimis temporibus coelitus innotuerunt,“Lond. 1676, 8vo. 7.” Euclidis Elementa Geometrica, novo ordine ac methodo fere, demonstrata. Una cum Nic. Mercatoris in Geometriam Introductione brevi, qua Magnitudinum Ortus ex genuinis Principiis, & Ortarum Affectiones ex ipsa Genesi derivantur," Lond. 1678, 12mo. His papers in the Philosophical Transactions are, 1. A Problem on some Points of Navigation vol. I. p. 215. 2. Illustrations of the Logarithmo-technia vol. Hi. p. 759. 3. Considerations concerning his Geometrical and Direct Method for finding the Apogees, Excentricities, and Anomalies of the Planets; vol. V. p. 1168. Mercator died in 1594, about fifty-four years of age.

an excellent mathematician and astronomer, was born April 17, 1656, at Dublin, where his father, a gentleman of good family and fortune, lived*. Being of a tender constitution, he was educated under a private tutor at home, till he was near fifteen, and then placed in the university of Dublin, under the care of Dr. PaJliser, afterwards archbishop of Cashell. He distinguished himself here by the probity of his manners as

Thus accomplished, hfc returned to Ireland in June 1678, and shortly after married Lucy, daughter of sir William Domvile, the king’s attorney-general. Being master of an easy fortune, he continued to indulge himself in prosecuting such branches of moral and experimental philosophy as were most agreeable to his fancy; and astronomy having the greatest share, he began, about 1681, a literary correspondence with Flamsteed, the king’s astronomer, which he kept up for several years. In 1683, he formed a design of erecting a philosophical society at Dublin, in imitation of the royal society at London; and, by the countenance and encouragement of sir William Petty, who accepted the office of president, they began a weekly meeting that year, when our author was appointed their first secretary. The reputation of his parts and learning, which by means of this society became more known, recommended him, in 1684, to the notice and favour of the duke of Ormond, then lord lieutenant of Ireland; by whose influence he was appointed that year, jointly with sir William Robinson, surveyor-general of his majesty’s buildings and works, and chief engineer. In 1685, he was chosen fellow of the royal society at London; and that year, for the sake of improving himself in the art of engineering, he procured an appointment from the Irish government, to view the most considerable fortresses in Flanders. Accordingly he travelled through that country and Holland, and some part of Germany and France; and carrying with him letters of recommendation from Flamsteed to Cassini, he was introduced to him, and other eminent astronomers, in the several places through which he passed. Soon after his return from abroad, he printed at Dublin, in 1686, his “Sciothericum telescopium,” containing a description of the structure and use of a telescopic dial invented by him: another edition of which was published at London in 1700, 4to. On the publication of sir Isaac Newton’s “Principia” the following year, 1687, our author was struck with the same astonishment as the rest of the world; but declared also, that he was not qualified to examine the particulars. Halley, with whom he constantly corresponded, had sent him the several parts of this inestimable treasure, as they came from the press, before the whole was finished, assuring him, that he looked upon it as the utmost effort of human genius.

, an eminent French astronomer and mathematician, was born at Paris, Nov. 23, 1715. His education was chiefly directed to the sciences, to which he manifested an early attachment; and his progress was such that at the age of twenty-one, he was chosen as the co-operator of Maupertuis, in the measure of a degree of the meridian at the polar circle. At the period when the errors in Flamsteed’s catalogue of the stars began to be manifest, he undertook to determine anew the positions of the zodiacal stars as being the most useful to astronomers. In 1743 he traced at St. Sulpice a grand meridian line, in order to ascertain certain solar motions, and also the small variations in the obliquity of the ecliptic.

, a celebrated mathematician, was born at Lyons in the year 1725, and giving early indications of a love of learning, was placed under the instructions of the Jesuits, with whom he acquired an intimate acquaintance with the ancient and modern languages, and some knowledge of the mathematics. At the age of sixteen he went to Toulouse to study the law, and was admitted an advocate, though without much intention of practising at the bar. Having completed his studies, he went to Paris, cultivated an acquaintance with the most distinguished literary characters, and it was owing to his intercourse with them, that he was induced to undertake his “History of the Mathematical Sciences.” But in the interim he published new editions, with additions and improvements, of several mathematical treatises which were already held in the highest estimation. The first of these was “Mathematical Recreations,” by M. Ozanam, which has been since translated into English, and published in London, in 4 vols. 8vo. To all the works which he edited, after Ozanam’s, he gave the initials of his name. He also contributed his assistance for some years to “The French Gazette;” and in 1755 he was elected a member of the Royal Academy of Sciences at Berlin. In the following year, when the experiment of inoculation was about to be tried on the first prince of the blood, Montucla translated from the English an account of all the recent cases of that practice, which had been sent from Constantinople, by lady Mary Wortley Montague. This translation he added to the memoir of De la Condamine on the subject. Previously to this publication, he had given to the world his “History of Inquiries relative to the Quadrature of the Circle.” The encouragement which this met with from very able judges of its merit, afforded him great encouragement to apply with ardour to his grand design, “The History of the Mathematics;” and in 1758 he published this “History,” in two volumes, 4to, which terminates with the close of the 17th century. It answered the expectations of all his friends, and of men of science in all countries, and the author was instantly elevated to a high rank in the learned world. His fame was widely diffused, and he was pressed from all quarters to proceed with the mathematical history of the 18th century, which he had announced for the subject of a third volume, and for which he had made considerable preparations; but he was diverted from his design, by receiving the appointment of secretary to the Intendance at Grenoble. Here he spent his leisure hours chiefly in retirement, and in scientific pursuits. In 1764, Turgot, being appointed to establish a colony at Cayenne, took Montucla with him as his “secretary,” to which was added the title of “astronomer to the king,” and although he returned without attaining any particular object with regard to the astronomical observations, for which he went out, he had an opportunity of collecting some valuable tropical plants, with which he enriched the king’s hothouses at Versailles. Soon after his return, he was appointed chief clerk in an official department, similar to that known in this country by the name of the “Board of Works,” which he retained till the place was abolished in 1792, when he was reduced to considerable pecuniary embarrassments. Under the pressure of these circumstances, he began to prepare a new and much enlarged edition of his “History,” which he presented to the world in 1799, in two volumes, quarto. In this edition are many important improvements; and many facts, which were barely announced in the former impression, are largely detailed and illustrated in this. After the publication of these two volumes, the author proceeded with the printing of the third; but death terminated his labours, when he had arrived at the 336th page. The remainder of the volume, and the whole of the fourth, were printed under the inspection of Lalande. Montucla had been a member of the National Institute from its original establishment. He had obtained various employments under the revolutionary government, though he was but meanly paid for his labour, and had to struggle with many difficulties to furnish his family with the bare necessaries of life. At length he was reduced to seek the scanty means of support by keeping a lottery-office, till the death of Saussure put him in the possession of a pension of about one hundred pounds per annum, which he enjoyed only four months. He died in December 1799, in the 75th year of his age. He was a man of great modesty, and distinguished by acts of generosity and liberality, when it was in his power. He was also friendly, cheerful, and of very amiable manners.

After the return of Charles II. he found great favour and promotion, becoming at length surveyor-general of the king’s ordnance, and receiving the honour of knighthood. He was a great favourite both with the king and the duke of York, who often consulted him, and were advised by him upon many occasions; and he often employed his interest with the court to the advancement of learning and the encouragement of merit. Thus he got Flamsteed house built in 1675, as a public observatory, recommended Mr. Flamsteed to be the king’s astronomer, to make the observations there: and being surveyor-general of the ordnance himself, this was the reason why the salary of the astronomer royal was made payable out of the office of ordnance. Being a governor of Christ’s hospital, it was by his interest that the king founded the mathematical school there, allowing a handsome salary for a master to instruct a certain number of the boys in mathematics and navigation, to qualify them for the sea-service. Foreseeing the great benefit the nation might receive from a mathematical school, if rightly conducted, he made it his utmost care to promote the improvement of it. The school was settled; but there still wanted a methodical institution from which the youths might receive such necessary helps as their studies required: a laborious work, from which his other great and assiduous employments might very well have exempted him, had not a predominant regard to a more general usefulness engaged him to devote al the leisure hours of his declining years to the improvement of so useful and important a seminary of learning.

Having thus engaged himself in the prosecution of this general design, he next sketched out the plan of a course or system of mathematics for the use of the school, and then drew up and printed several parts of it himself, when death. put an end to his labours, before the work was completed. He died at Godalming, in his way from Portsmouth to London, August 27, 1679. Pieces of cannon, amounting to the number of his years, were discharged at the Tower, during his funeral. He was buried in the chapel of the Tower, where is a monument and inscription, which has enabled us to correct the mistakes 6f his biographers as to his age, place of birth, &c. In 1681, his great work was published by his sons-in-law, Mr. Hanway and Mr. Potinger. Of this work, the arithmetic, practical geometry, trigonometry, and cosmography, were written by sir Jonas himself, and printed before his death. The algebra, navigation, and the books of Euclid, were supplied by Mr. Perkins, the then master of the mathematical school. And the astronomy, or doctrine of the sphere, was written by Mr. Flamsteed, the astronomer royal. He always intended to have left his collection of mathematical books to the Royal Society, of which he was a fellow, but he died without a will. His only son, Jonas, had the honour of knighthood conferred on him, and the reversion of his father’s place of surveyor- general of the ordnance; “but,” adds Aubrey, “young sir Jonas, when he is old, will never be old sir Jonas, for all the gazette’s eulogie.”

The first time-keeper, after it had been tried by Mr. Maskelyne, astronomer-royal, was in possession of M. de Zach (astronomer to the duke of Saxe Gotha) from May 1786 to July 1788, during which time he carried it from London to Gotha, thence to Hieres, thence by sea to Genoa, thence by land to Pisa, Milan, and back to Hieres. At the end of about a year’s absence from Gotha (to which he returned by Geneva) after having travelled over several thousand miles, he found that it had preserved the same regularity of going which it had when it first came into his possession; and by its very great accuracy, he was enabled to ascertain the longitude of several places with a greater degree of precision than had ever been done before.

In 1784 and 1785, this time-keeper was carried two royages to Newfoundland by the late admiral Campbell, and in each voyage went so well as to determine the longitude within one mile and a quarter on the first voyage, and to six miles and an eighth on the second. In consequent e of this, it was the admiral’s opinion that such time-keepers were capable of answering every nautical purpose tin; could be required of them. After Mr. Mudge had received the 5001. instead of making only one more time-keeper, which would have been sufficient to answer the purposes of the act, he immediately set about making two, and when completed, they likewise^ pursuant to the act, underwent a trial by the astronomer-royal.

, commonly called Regiomontanus, from his native place, Mons Regius, or Koningsberg, a town in Franconia, was born in 1436, and became the greatest astronomer and mathematician of his time. He was indeed a very prodigy for genius and learning. Having first acquired grammatical learning in his own country, he was admitted, while yet a boy, into the academy at Leipsic, where he formed a strong attachment to the mathematical sciences, arithmetic, geometry, astronomy, &c. But not finding proper assistance in these studies at this place, he removed, at only fifteen years of age, to Vienna, to study under the famous Purbacb, the professor there, who read lectures in those sciences with the highest reputation. A strong and affectionate friendship soon took place between these two, and our author made such rapid improvement in the sciences, that he was able to be assisting to his master, and to become his companion in all his labours. In this manner they spent about ten years together, elucidating obscurities, observing the motions of the heavenly bodies, and comparing and correcting the tables of them, particularly those of Mars, which they found to disagree with the motions, sometimes as much as two degrees.

, celebrated by ancient writers as a philosopher, astronomer, and poet, was, according to Plato and Diodorus Siculus, an Athenian, the son of Orpheus, and chief of the Eleusinian mysteries, instituted at Athens in honour of Ceres; or, according to others, he was only the disciple of Orpheus. He is allowed to have been one of the first poets who versified the oracles. He is placed in the Arundelian marbles, Epoch 15, 1426 B.C. at which time his hymns are there said to have been received in the celebration of the Eleusinian mysteries. Laertius tells us, that Musæus not only composed a theogony, but formed the first sphere but he was probably misled by the title of a poem said to have been written by Mnsaeus, “de Sphaera.” The doctrine which he taught was, that all things are produced fiom one, and shall be resolved into the same; an Orphic doctrine, which is the first principle of the system of emanation, and the foundation of all the ancient theogonies. He is celebrated by Virgil in the character of Hierophant, or priest of Ceres, among the most illustrious mortals who have merited a place in Elysium, and is made the conductor of Æneus to the recess, where he meets the shade of his fatber Anchises.

, a learned Spanish physician, divine, and botanist, was born at Cadiz in 1734. He studied medicine at his native place and at Seville, and having obtained much reputation, was appointed professor of anatomy at Madrid, where he signalized himself by his physiological knowledge. In 1760 the marquis della Vega, being appointed viceroy of New Granada, solicited Mutis to accompany him as his physician. On his arrival at Santa Fe de Bogota, the capital of New Granada, Mutis, by permission of the viceroy, undertook to introduce the mathematics as a branch of study in the university, and his lectures on that subject were heard with attention and admiration, and he was at length, by the authority of the Spanish government, established professor of philosophy, mathematics, and natural history, at Santa Fe. While enjoying this post, some unfortunate speculations in the mines, which exhausted his pecuniary resources, occasioned his taking orders in the church, and his clerical duties now shared a considerable portion of his time. Part of it likewise was employed in botanical researches, and he corresponded with Linnæus, to whom he sent numerous specimens [of his own discover) 7 particularly the Mutisia, so named in honour of him by Linnæus. In 1776 he settled at Sapo, in the government of Mariquita, where he had many enviable opportunities of discovering and collecting singular plants and flowers. In 1778 don Antonio Caballeroy Gorgora, the new archbishop, on his arrival at Santa Fe, discovered the superior merits of Mutis, and determined to extricate him from his difficulties, and procure him a pension, with the appointment of botanist and astronomer to the king. Accordingly, under the patronage of this liberal prelate, he became the superintendant of a botanical school for investigating the plants of America. In 1783, attended by some of his pupils, and several draughtsmen, he made a tour through the kingdom of New Granada; and by his diligence much new light was thrown upon the history of the Peruvian bark, and its various species. He also taught his countrymen the culture and the value of indigo. His health having suffered from the climate of Mariquita, he was directed to repair to Santa F, and to fix on some of his pupils, whose y; uth and constitutions might be more adequate to such labours. In 1797 he had an opportunity to visit Paris, to consult with Jussieu, and the other eminent botanists of that capital, concerning the composition of a “Flora Bogotensis,” and to make himself master of all the new improvements and discoveries. He remained at Paris till 1801, when he went back to Madrid. Whether he subsequently returned to his native country, we know not, but in 1804 he was appointed to the professorship of Botany, and superintendance of the royal garden at Madrid. Although his advancing age made repose now in some measure necessary, he continued to be serviceable to the government of his native country, and to the prosperity of that in which he had so long been naturalized. He lived to an advanced age, but of the precise date of his death we are not informed.

, a learned traveller, whose German name was Oelschlager, was born in 1599, or 1600, at Aschersieben, a small town in the principality of Anhalt. 43is parents were very poor, and scarcely able to maintain him, yet by some means he was enabled to enter as a student at Leipsic, where he took his degrees in arts and philosophy, but never was a professor, as some biographers have asserted. He quitted Leipsic for Holsteiu, where the duke Frederic, hearing of his merit and capacity, wished to employ him. This prince having a wish to extend the commerce of his country to the East, determined to send an embassy to the Czar Michael Federowitz, and the king of Persia, and having chosen for this purpose two of his counsellors, Philip Crusius and Otto Bruggeman, he appointed Olearius to accompany them as secretary. Their travels lasted six years, during which Olearius collected a great fund of information respecting the various countries they visited. The Czar of Moscovy on his return wished to have retained him in his service, with the appointment of astronomer and mathematician; not, however, his biographers tell us, so much on account of his skill in these sciences, as because the Czar knew that Olearius had very exactly traced the course of the Volga, which the Russians then wished to keep a secret from foreigners. Olearius had an inclination, however, to have accepted this offer, but after his return to the court of Holstein, he was dissuaded from it, and the duke having apologized to the Czar, attached him to himself as mathematician and antiquary. In 1643, the duke sent him on a commission to Moscow, where, as before, his ingenuity made him be taken for a magician, especially as on this occasion he exhibited a camera obscura. In 1650 the duke appointed him his librarian, and keeper of his curiosities. The library he enriched with many Oriental Mss. which he had procured in his travels, and made also considerable additions to the duke’s museum, particularly of the collection of Paludanns, a Dutch physician, which the duke sent him to Holland ta purchase; and he drew up a description of the whole, which was published at Sleswick in 1666, 4to. He also constructed the famous globe of Gottorp, and an armillary sphere of copper, which was not less admired, and proved how much mathematics had been his study. He died Feb. 22, 1671. He published, in German, his travels, 1647, 1656, 1669, fol. Besides these three editions, they were translated into English by Davies, and into Dutch and Italian. The most complete translation is that, in French, by Wicquefort, Amst. 1727, 2 vols. fol. who also translated Olearius’s edition of Mandelso’s “Voyages to Persia,” c. fol. Among his other and less known works, are some lives of eminent Germans “The Valley of Persian Roses,” from the Persian; “An abridged Chronicle of Holstein,” &c

, an able mathematician of France, aud one of the most learned astronomers of the seventeenth century, was born at Fleche, and became priest and prior of Rillie in Anjou. Coming afterwards to Paris, his superior talents for mathematics and astronomy soon made him known and respected. In 1666 he was appointed astronomer in the Academy of Sciences. And five years after, he was sent, by order of the king, to the castle of Urani burgh, built by Tycho Brahe in Denmark, to make astronomical observations there; and from thence he brought the original manuscripts written by Tycho Brahe; which are the more valuable, as they differ in many places from the printed copies, and contain a book more than lias yet appeared. These discoveries were followed by many others, particularly in astronomy: he was one of the first who applied the telescope to astronomical quadrants: he first executed the work called “La Connoissance des Temps,” which he calculated from 1679 to 1683 inclusively: he first observed the light in the vacuum of the barometer, or the mercurial phosphorus: he also first of any went through several parts of France, to measure the degrees of the French meridian, and first gave a chart of the country, which the Cassini’s afterwards carried to a great degree of perfection. He died in 1682 or 1683, leaving a name dear to his friends, and respectable to his contemporaries and to posterity. His works are: 1. “A treatise on Levelling.” 2. “Practical Dialling by calculation.” 3. “Fragments of Dioptrics.” 4. “Experiments on Running Water.” 5. “Of Measurements.” 6. “Mensuration of Fluids and Solids.” 7. ' Abridgment of the Measure of the Earth.“8.” Journey to Uraniburgh, or Astronomical Observations made in Denmark.“9.” Astronomical Observations made in divers parts of France.“10” La Connoissance des Temps," from 1679 to 1683.

, a French mathematician and astronomer, was born at Paris, in 1711. In 1727 he became a member of the canons regular of the congregation of France. He was intended for the church, hut the freedom of his opinions displeased his superiors, and after a few years’ study of theology, he devoted himself entirely to the sciences. In 1749 he was appointed a member of the academy of sciences in Rouen, and was elected to fill the office of astronomer, and attained to first-rate excellence. His earliest production, as an author, was the “Calculation of an Eclipse of the Moon,” on the 23d of December 1749. Lacaille had calculated it at Paris; but the calculations differed by four minutes: Lacaille., however confessed his error, and received Pingre into his friendship. In May 1753 he was elected correspondent of the Academy of Sciences at Paris, after having sent them an observation of the transit of Mercury, which he made at Rouen. He was next appointed librarian of the abbey of St. Genevieve, obtained the construction of an observatory, and was furnished by the abbot and chapter with a six-foot telescope, while he had the loan of an excellent quadrant from the academy. At the desire of Le Monnier, he next engaged in calculating “A Nautical Almanack,” to enable navigators more easily to ascertain the longitude by means of lunar observations. He calculated a table of the eclipses visible of the sun and moon from the commencement of the Christian aera to 1900, and afterwards a table of the eclipses visible from the northern pole to the equator, for a thousand years before our aera. The utility of these labours for verifying historical dates, induced the Academy of Inscriptions to insert a part of them in the forty-second volume of their Memoirs. He published the “State of the Heavens” for 1754: in this the moon’s place was calculated with the utmost exactness according to the tables of Dr. Halley for noon and midnight, with the right ascension in seconds of time twice a day. In 1753 he published “A Memoir relating to the Discoveries made in the South Sea, during the Voyages of the English and French round the World.” In 1760, Pingre left France for the island of Rodriguez, in the Indian ocean, to observe the transit of Venus, that was to take place in the following year; and on the 6th of June of that year he made his observations, from which he concluded that the parallax, of the sun was 10“. 2. At the same time the English astronomer Mason concluded, from the observations which he made at the Cape of Good Hope, that the parallax was 8”. 2. La Lande, in his “Astronomy,” published in 1764, adopted a medium between these conclusions, and supposed l,he parallax to be 9“, in which he was followed by astronomers in general, till more numerous observations, made on the transit of 1769, led to a different result. After the return of Pingre from the East, he published a description of Pekin, in which he shewed the position of that capital from the result of a number of calculations of eclipses; and ascertained its longitude by other calculations, with a degree of precision to which none of the labours of the scientific missionaries had any pretensions. In 1769 he sailed for the island of St. Domingo, on board the Isis man of war, to observe the transit of Venus, and performed the service committed to him in the most able and satisfactory manner possible. An account of this voyage, which proved of considerable importance to the science of geography, as well as astronomy, appeared in 1773, in two vols. 4to. After comparing the results of the immense number of calculations made by the observers of the transit in 1769J the sun’s parallax has been concluded to be about 8”. 6. In 1771, Pingre made another voyage, on board the Flora frigate, with a view of extending the interests of geographical and astronomical knowledge, having with him, as the companion of his pursuits, the chevalier de Borda, a celebrated engineer and geometrician. The account of their proceedings, observations, and experiments, was published in 1778, in two vols. 4to. In 1784, M. Pingre published his “Cometography, or historical and theoretical treatise on Comets,” in two vols. 4tc, which is his most considerable work, and contains calculations of the orbits of all the comets of which an. account has been preserved. After a long life, spent in the most important services to the world, he died in the month of May 179tf, leaving behind him a high character for integrity, having enjoyed the esteem of the public, as well as that of his friends. He was author of many other works besides those that have been already noticed.

, a great geographer, mathematician, and astronomer of antiquity, was born at Pelusium, in Egypt, about the year 70, and flourished in the reigns of Adrian and Marcus Antoninus. He tells us himself, in one place, that he made a great number of ob* servations upon the fixed stars at Alexandria, in the second year of Antoninus Pius and in another, that he observed an eclipse of the moon in the ninth year of Adrian, whence it is reasonable to conclude that this astronomer’s observations upon the heavens were made between A. D. 125, and A. D. 140. Hence appears the error of some authors in supposing that this Claudius Ptolemy was the same with the astrologer Ptolemy, who constantly attended Galba, promised Otho that he should survive Nero, and afterwards that he should obtain the empire; which is as improbable as what Isidorus, an ecclesiastical writer of the seventh century, and some modems after him, have asserted; namely, that this astronomer was one of the kings of Egypt. We know no circumstances of the life of Ptolemy but it is noted in his Canon, that Antoninus Pius reigned three-and-twenty years, which shews that himself survived him.

Science is greatly indebted to this astronomer, who has preserved and transmitted to us the observations and principal discoveries of the ancients, and at the same time augmented and enriched them with his own. He corrected Hipparchus’s catalogue of the fixed stars; and formed tables, by which the motions of the sun, moon, and planets, might be calculated and regulated. He was indeed the first who collected the scattered and detached observations of the ancients, and digested them into a system which he set forth in his “Μεγαλη συνταξις, sive Magna Constructio,” divided into thirteen books, and which has been called from him the Ptolemaic system, to distinguish it from those of Copernicus and Tycho Brahe. About the year 827, this work was translated by the Arabians into their language, in which it was called “Almagestum,” by the command of one of their kings and from Arabic into Latin, about 1230, under the encouragement of the emperor Frederic II. There were other versions from the Arabic into Latin and a manuscript of one, done by Girardus Cremonensis, who flourished about the middle of the fourteenth century, is said by Fabricius to be still extant, and in the library of All Souls college at Oxford. The Greek text began to be read in Europe in the fifteenth century and was first published by Simon Grynaeus, at Basil, 1538, in folio, with the eleven books of commentaries by Theon, who flourished at Alexandria in the reign of the elder Theodosius. In 1454, it was reprinted at Basil, with a Latin version by Georgius Trapezuntius and again at the same place in 1551, with the addition of other works of Ptolemy, to which are Latin versions by Camerarius. We learn from Kepler, that this last edition was used by Tycho.

, a very eminent mathematician and astronomer, was born at Purbach, a town upon the confines of Bavaria and Austria, in 1423, and educated at Vienna. He afterwards visited the most celebrated universities in Germany, France, and Italy; and found a particular friend and patron in cardinal Cusa, at Rome. Returning to Vienna, he was appointed mathematical professor, in which office he continued till his death, which happened in 1461, in the 39th year of his age only, to the great loss of the learned world.

, a French mathematician and astronomer, was born at Montpellier, Sept. 1, 1722, and from his earliest years became attached to the study of the sciences, particularly mathematics. When very young, he was appointed secretary to the Montpellier academy of sciences, which office he held until all academies in France were dissolved. In the course of his office, he published two volumes of their “Memoirs/' and was preparing a third at the time of the revolution. He also contributed many valuable papers himself on philosophical and mathematical subjects, and furnished some articles for the” Dictionnaire Encyclopedique.“The comet of 1759, the subject of so much prediction and expectation, so far altered his pursuits as to make them afterwards centre in astronomy. He was for a long time considered as the only good astronomer at Montpellier, and made many useful observations, particularly on the famous transit of Venus in 1761. Such was his zeal, that when old age prevented him from making observations with his usual accuracy, he maintained a person for that purpose at his own expence as keeper of the observatory at Montpellier. On the death of his father, in 1770, he became counsellor of the court of aids, and was often the organ of that company on remarkable occasions. In 1793, when such members of the old academy as had esdaped the murderous period of the revolution attempted to revive it under the name of” Societe* Libre des sciences et belles lettres de Montpeliier,“De Ratte was chosen president. Some volumes of their transactions have been published under the title of” Bulletins." When the national institute was formed, De Ratte was chosen an associate, and also a member of other learned societies in France, and at last one of the legion of honour. He died Aug. 15, 1805, aged eighty-three. His astronomical observations have been collected for publication by M. De Flaugergues, an astronomer of Viviers; but our authority does not mdntipn whether they haV yet appeared.

, an eminent astronomer and mathematician, was born at Salfeldt in Thuringia, a province in Upper Saxony, the llth of October, 1511. H^ studied mathematics under James Milichi at Wittemberg, in which university he afterwards became professor of those sciences, which he taught with great applause. After writing a number of useful and learned works, he died February 19, 1553, at 42 years of age only. His writings are chiefly the following: 1. “Theorize novae Planetarum G. Purbachii,” augmented and illustrated with diagrams and Scholia in 8vo, 1542; and again in 1580. In this work, among other things worthy of notice, he teaches (p. 75 and 76) that the centre of the lunar epicycle describes an ovalfgure in each monthly period, and that the or hit of Mercury is also of the same oval figure. 2. “Ptolomy’s Almagest,” the first book, in Greek, with a Latin version, and Scholia, explaining the more obscure passages, 1549, 8vo. At the end of p. 123 he promises an edition of Theon’s Commentaries, which are wry useful for understanding Ptolomy’s meaning; but his immature death prevented Reinhold from giving this and other works which he had projected. 3. “Prutenicse Tabulae Ccelestiurn Motuum,” 1551, 4to; again in 1571; and also iii 1585. Reinhold spent seven years labour upon this work, in which he was assisted by the munificence of Albert, duke of Prussia, from whence the tables had their name. Reinhold compared the observations of Copernicus with those of Ptolomy and Hipparchus, from whence he constructed these new tables, the uses of which he has fully explained in a great number of precepts and canons, forming a complete introduction to practical astronomy. 4. “Primus liber Tabularum Directionum” to which are added, the “Canon Fcecundus,” or Table of Tangents, to every minute of the quadrant and New Tables of Climates, Parallels, and Shadows, with an Appendix containing the second Book of the Canon of Directions; 1554, 4to. Reinhold here supplies what was omitted by Regiomontanus in his Table of Directions, &c.; shewing the finding of the sines, and the construction of the tangents, the sines being found to every minute of the quadrant, to the radius 10,000,000; and he produced the Oblique Ascensions from 60 degrees to the end of the quadrant. He teaches also the use of these tables in the solution of spherical problems.

, a celebrated German astronomer and mathematician, was born at Feldkirk in Tyrol, February 15, 1514. After imbibing the elements of the mathematics at Zurick with Oswald Mycone, he went to Wittemberg, where he diligently cultivated that science, and was made master of philosophy in 1535, and professor in 1537. He quitted this situation, however, two years after, and went to Fruenburg to profit by the instructions of the celebrated Copernicus, who had then acquired great fame. Rheticus assisted this astronomer for some years, and constantly exhorted him to perfect his work “De Revolutionibus,” which he published after the death of Copernicus, viz. in 1543, folio, atNorimberg, together with an illustration of the same, dedicated to Schoner. Here too, to render astronomical calculations more accurate, he began his very elaborate canon of sines, tangents and secants, to 15 places of figures, and to every 10 seconds of the quadrant, a design which he did not live quite to complete. The canon of sines however to that radius, for every 10 seconds, and for every single second in the first and last degree of the quadrant, computed by him, was published in folio at Francfort, 1613, by Pitiscus, who himself added a few of the first sines computed to 22 places of figures. But the larger work, or canon of sines, tangents, and secants, to every 10 seconds, was perfected and published after his death, viz. in 1596, by his disciple Valentine Otho, mathematician to the electoral prince palatine; a particular account and analysis of which work may be seen in the Historical Introduction to Dr. Button’s Logarithms.

, a learned Italian astronomer, philosopher, and mathematician, was born in 1598, at Ferrara, a city in Italy, in the dominions of the pope. At sixteen years of age he was admitted into the society of the Jesuits, and the progress he made in every branch of literature and science was surprising. He was first appointed to teach rhetoric, poetry, philosophy, and scholastic divinity, in the Jesuits’ colleges at Parma and Bologna; yet applied himself in the mean time to making observations in geography, chronology, and astronomy. This was his natural bent, and at length he obtained leave from his superiors to quit all other employment, that he might devote himself entirely to those sciences.

, or Rømer (Olaus), a Danish astronomer and mathematician, was born at Arhusen in Jutland in 1644; and, at eighteen, was sent to the university of Copenhagen. He applied himself assiduously to the study of mathematics and astronomy, and became such an adept in those sciences, that, when Picard was sent by Lewis XIV. in 1671, to make observations in the North, he was so pleased with him, that he engaged him to return with him to France, and had him presented to the king, who ordered him to teach the dauphin mathematics, and settled a pension on him. He was joined with Picard and Cassini, in making astronomical observations; and, in 1672, was admitted a member of the academy of sciences. During the ten years he resided at Paris, he gained a prodigious reputation by his discoveries; yet is said. to have complained afterwards that his coadjutors ran away with the honour of many things which belonged to him. In 1681, Christian V. king of Denmark called him back to his own country, and made him professor of astronomy at Copenhagen. He employed him also in reforming the coin and the architecture, in regulating the weights and measures, and in measuring the high roads throughout the kingdom. Frederic IV. the successor of Christian, shewed the same favour to Roemer, and conferred new dignities on him. He was preparing to publish the result of his observations, when he died Sept. 19, 1710, aged 66; but some of his observations, with his manner of making those observations, were published in 1735, under the title of “Basis Astronomise,” by his scholar Peter Horrebow, then professor of astronomy at Copenhagen. Roemer was the first who found out the velocity with which light moves, by means of the eclipses of Jupiter’s satellites. He had observed for many years that, when Jupiter was at his greatest distance from the earth, where he could be observed, the emersions of his first satellite happened constantly 15 or J 6 minutes later than the calculation gave them. Hence he concluded that the light reflected by Jupiter took up this time in running over the excess of distance, and consequently that it took up 16 or 18 minutes in running over the diameter of the earth’s orbit, and 8 or in coming from the sun to us, provided its velocity was nearly uniform. This discovery had at first many opposers but it was afterwards confirmed by Dr. Bradley in the most ingenious and beautiful manner.

He died Jan. 24, 1708-9, in his fifty-eighth year, and was buried in Canterbury cathedral, where a monument is erected to his memory. In his private life he was a good husband, and a kind master, lived hospitably towards his neighbours, and left behind him a moderate fortune; so moderate, that when he came to make his will it surprized those who were present; but sir George assigned the reason in a few words, “I do not leave much,” said he, i( but what I leave was honestly gotten it never cost a sailor a tear, or the nation a farthing." 1 Rooke (Lawrence), an English astronomer and geometrician, was born at Deptford, in Kent, 1623, and educated at Eton school, whence he removed to King’s college, Cambridge, in 1639. After taking the degree of M. A. in 1647, he retired for some time into the country, but in 1650 went to Oxford, and settled in Wadham college, that he might associate with Dr. Wilkins, and Mr. Seth Ward the astronomy professor; and also accompany Mr. Boyle in his chemical operations. After the death of Mr. Foster he was chosen astronomy professor in Gresham college, London, in 1652. He made some observations upon the comet at Oxford, which appeared in the month of December that year; which were printed by Mr. Seth Ward the year following. And, in 1655, Dr. Wallis publishing his treatise on conic sections, he dedicated that work to those two gentlemen. In 1657 Mr. Rooke was permitted to exchange the astronomy professorship for that of geometry. This step might seem strange, as astronomy still continued to be his favourite study; but it was thought to have been from the convenience of the lodgings, which opened behind the reading hall, and therefore were proper for the reception of those gentlemen after the lectures, who, in 1660, laid the foundation of the royal society. Most of those learned men who had been accustomed to assemble with him at Oxford, coining to London, joined with other philosophical gentlemen, and usually met at Gresham college to hear Mr. Rooke’s iectwes, and afterwards withdrew into his apartment; till their meetings were interrupted by the quartering of soldiers in the college in 1658. And after the royal society came to be formed into a regular body, Mr. Rooke was very zealous and serviceable in promoting that great and useful institution; though he did not live till it received its establishment by the royal charter.

, a considerable mathematician and astronomer, was born at Mundeilheitn in Schwaben, in 1575. He entered into the society of the Jesuits whenhe was twenty; and afterwards taught the Hebrew tongue and the mathematics at Ingolstadt, Friburg, Brisac, and Rome. At length, he became rector of the college of the Jesuits at Neisse in Silesia, and confessor to the archduke Charles. He died in 1650, at the age of seventylive.

, an eminent mathematician, mechanist, and astronomer, was descended from an ancient family at Little-Horton, near Bradford, in the West Riding of Yorkshire, where he was born about 1651. He was at first apprenticed to a merchant at Manchester, but his inclination and genius being decidedly for mathematics, he obtained a release from his master, and removed to Liverpool, where be gave himself up wholly to the study of mathematics, astronomy, &c. and for a subsistence, opened a school, and taught writing and accounts, &c. Before he had been long at Liverpool, he accidentally met with a merchant or tradesman visiting that town from London, in whose house the astronomer Mr. Flamsteed then lodged; and such was Sharp’s enthusiasm for his favourite studies, that with the view of becoming acquainted with this emiment man, he engaged himself to the merchant as a bookkeeper. Having been thus introduced, he acquired the friendship of Mr. Flamsteed, who obtained for him a profitable employment in the dock-yard at Chatham. In this he continued till his friend and patron, knowing his great merit in astronomy and mechanics, called him to his assistance, in completing the astronomical apparatus in the royal observatory at Greenwich, which had been built about the year 1676.

, a mathematician and astronomer of great talents, was born about 1734, and rose from a low situation, little connected with learning, to some of the first ranks in literary pursuits. His early labours contributed to the “Ladies Diary,” a useful little work which has formed many eminent mathematicians. In 1761) he was deemed a fit person to be sent to Hudson’s Bay to observe the transit of Venus over the sun; and the manner hi which he discharged that trust did honour to his talents.

On his return he communicated to the royal society an excellent paper of observations made at that station, which was inserted in their Transactions; and the year following, his general observations made at Hudson’s Bay were published in a large quarto volume. He next, in the character of astronomer, accompanied capt. Cook in his first voyage. 1772 1774, and again iti his other voyage of 1776 1779. In 1777 appeared his “Observations on a Voyage with captain Cook;” and in 1778, “Remarks on Dr. Fovster’s Account of the Voyage,” in which he showed considerable talents as a controversial writer. Soon after his return from his last voyage he was elected a fellow of the royal society, and proved a very useful member; and on the death of Mr. Daniel Harris he was appointed mathematical master to Christ’s Hospital, London, and some years after, secretary to the board of longitude, both which offices he held till the time of his death, which happened in 1798, in the sixty-fourth year of his age. In 1781 he published an “Enquiry into the state of the Population in England and Wales,” and in 1794 his treatise on the longitude by time-keepers. He published also an ingenious restoration of one of the lost pieces of Apollonius; and it has been said, was author of one of the dissertations on the achronical rising of the Pleiades, annexed to Dr. Vincent’s Voyage of Nearch us. Besides these he wrote some ingenious papers in the Philosophical Transactions, and in various periodical publications, particularly the “Ladies Diary,” sometimes signed with his own name, and sometimes under certain fictitious signatures. T

, a good astronomer and mathematician, was born in 1728. He was maternally descended from the celebrated clock and watchmaker, Daniel Quare, in which business he was himself brotignt up, and was educated in the principles of the Quakers, all his progenitors for many generations having been of that community, whose simplicity of manners he practised through life. It appears that he cultivated the study of astronomy at a very early age, as he had a communication on that subject in the “Gentleman’s Diary” for 1741, which must have been written when he was thirteen years of age. Soon after this he became a frequent writer both in the Diaries and in the Gentleman’s Magazine, sometimes under his own name, but oftener with the initials G. W. only. In 1764 he published a map, exhibiting the passage of the moon’s shadow over England in the great solar eclipse of April 1, that year; the exact correspondence of which to the observations gained him great reputation. In the following year he presented to the commissioners of longitude a plan for calculating the effects of refraction and parallax, on the, moon’s distance from the sun or a star, to facilitate the discovery of the longitude at sea. Having taught mathematics in London for many years with much reputation, he was in 1767 elected F. R. S. and appointed head master of the royal naval academy at Portsmouth, where he died of a paralytic stroke in 1785, aged fiftyseven.