MOORE (Sir Jonas)

, a very respectable mathematician, Fellow of the Royal Society, and Surveyorgeneral of the Ordnance, was born at Whitby in Yorkshire about the year 1620. After enjoying the advantages of a liberal education, he bent his studies principally to the mathematics, to which he had al- ways a strong inclination. In the expeditions of King Charles the 1st into the northern parts of England, our author was introduced to him, as a person studious and learned in those sciences; when the king expressed much approbation of him, and promised him encouragement; which indeed laid the foundation of his fortune. He was afterwards appointed mathematical master to the king's second son James, to instruct him in arithmetic, geography, the use of the globes, &c. During Cromwell's government it seems he followed the profession of a public teacher of mathematics; for I find him styled, in the title-page of some of his publications, “professor of the mathematics.” After the return of Charles the 2d, he found great favour and promotion, becoming at length surveyor-general of the king's ordnance. He was it seems 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 it must be owned that 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, recommending 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 seems that by his interest 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. Here he soon found an opportunity of exerting his abilities in a manner somewhat answerable to his wishes, namely, that of serving the rising generation. And considering with himself the 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 all 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. I have not found in what year this happened; but it must have been but little before 1681, the year in which the 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.|

The list of Sir Jonas's works, as far as I have seen them, are the following:

1. The New System of Mathematics; above mentioned, in 2 vols 4to, 1681.

2. Arithmetic in two books, viz, Vulgar Arithmetic and Algebra. To which are added two Treatises, the one A new Contemplation Geometrical, upon the Oval Figure called the Ellipsis; the other, The two first books of Mydorgius, his Conical Sections analized &c. 8vo, 1660.

3. A Mathematical Compendium; or Useful Practices in Arithmetic, Geometry, and Astronomy, Geography and Navigation, &c, &c. 12mo, 4th edition in 1705.

4. A General Treatise of Artillery: or, Great Ordnance, Written in Italian by Tomaso Moretii of Brescia. Translated into English, with notes thereupon, and some additions out of French for Sea-Gunners. By Sir Jonas Moore, Kt. 8vo, 1683.

MORTALITY. Bills of Mortality, are accounts or registers specifying the numbers born, and buried, and sometimes married, in any town, parish, or district. These are of great use, not only in the doctrine of Life Annuities, but in shewing the degrees of healthiness and prolificness, with the progress of population in the places where they are kept. It is therefore much to be wished that such accounts had always been correctly kept in every kingdom, and regularly published at the end of every year. We should then have had under inspection the comparative strength of every kingdom, as far as it depends on the number of inhabitants, and its increase or decrease at different periods.

Such accounts are rendered still more useful, when they include the ages of the dead, and the distempers of which they have died. In this case they convey some of the most important instructions, by furnishing the means of ascertaining the law which governs the waste of human life, the values of annuities dependent on the continuance of any lives, or any survivorships between them, and the favourableness or unfavourableness of different situations to the duration of human life.

There are but few registers of this kind; nor has this subject, though so interesting to mankind, ever engaged much attention till lately. Indeed, bills of Mortality for the several parishes of the city of London have been kept from the year 1592, with little interruption; and a very ample account of them has been published down to the year 1759, by Dr. Birch, in a large 4to vol. which is perhaps the fullest work of the kind extant; containing besides the bills of Mortality, with the diseases and casualties, several other valuable tracts on the subject of them, and on political arithmetic, by several other authors, as Capt. John Graunt, F. R. S.; Sir William Petty, F. R. S.; Corbyn Morris, Esq. F. R. S.; and J. P. Esq. F. R. S.; the whole forming a valuable repository of materials; and it would be well if a continuation were published down to the present time, and so continued from time to time.

Bills containing the ages of the dead, were long since published for the town of Breslaw in Silesia. It is well known what use has been made of these by Dr. Halley, and after him by Mr. De Moivre. A table of the probabilities of the duration of human life at every age, deduced from them by Dr. Halley, was published in the Philos. Trans. vol. 17, and has been inserted in this work under the article Life-Annuities; which is the first table of this kind that has been published. Since the publication of this table, similar bills have been established in many other places, in England, Germany, Switzerland, France, Holland, &c, but most especially in Sweden; the results of some of which may be seen in the large comparative table of the duration of life, under the article Life-Annuities, in this work.