WREN (Sir Christopher)

, a great philosopher and mathematician, and one of the most learned and eminent architects of his age, was the son of the rev. Christopher Wren, dean of Windsor, and was born at Knoyle in Wiltshire in 1632. He studied at Wadham college, Oxford; where he took the degree of master of arts in 1653, and was chosen fellow of Allsouls college there. Soon after, he became one of that ingenious and learned society, who then met at Oxford for the improvement of natural and experimental philosophy, and which at length produced the Royal Society.

When very young, he discovered a surprising genius for the mathematics, in which science he made great advances before he was 16 years of age.—In 1657 he was made professor of astronomy in Gresham college, London; and his lectures, which were much frequented, tended greatly to the promotion of real knowledge: in his inaugural oration, among other things, he proposed several methods by which to account for the shadows returning backward 10 degrees on the dial of king Ahaz, by the laws of nature. One subject of his lectures was upon telescopes, to the improvement of which he had greatly contributed: another was on certain properties of the air, and the barometer. In the year 1658 he read a description of the body and different phases of the planet Saturn; which subject he proposed to investigate while his colleague, Mr. Rooke, then professor of geometry, was carrying on his observations upon the satellites of Jupiter. The same year he communicated some demonstrations concerning cycloids to Dr. Wallis, which were afterwards published by the doctor at the end of his treatise upon that subject. About that time also, he resolved the problem proposed by Pascal, under the feigned name of John de Montford, to all the English mathematicians; and returned another to the mathematicians in France, formerly proposed by Kepler, and then resolved likewise by himself, to which they never gave any solution.— In 1660, he invented a method for the construction of solar eclipses: and in the latter part of the same year, he with ten other gentlemen formed themselves into a society, to meet weekly, for the improvement of natural and experimental philosophy; being the foundation of the Royal Society.—In the beginning of 1661, he was chosen Savilian professor of astronomy at Oxford, | in the room of Dr. Seth Ward; where he was the same year created Doctor of Laws.

Among his other accomplishments, Dr. Wren had gained so considerable a skill in architecture, that he was sent for the same year, from Oxford, by order of king Charles the 2d, to assist Sir John Denham, surveyor general of the works.—In 1663, he was chosen fellow of the Royal Society; being one of those who were first appointed by the Council aster the grant of their charter. Not long after, it being expected that the king would make the society a visit, the lord Brounker, then president, by a letter requested the advice of Dr. Wren, concerning the experiments which might be mo<*>proper on that occasion: to whom the doctor recommended principally the Torricellian experiment, and the weather needle, as being not mere amusements, but useful, and also neat in their operation. Indeed upon many occasions Dr. Wren did great honour to that illustrious body, by many curious and useful discoveries, in astronomy, natural philosophy, and other sciences, related in the History of the Royal Society, where Dr. Sprat has inserted them from the registers and other books of the society to 1665. Among others of his productions there enumerated, is a lunar globe; representing the spots and various degrees of whiteness upon the moon's surface, with the h<*>s, eminences and cavities: the whole contrived fo, that by turning it round to the light, it shews all the lunar phases, with the various appearances that happen from the shadows of the mountains and valleys, &c: this lunar model was placed in the king's cabinet. Another of these productions, is a tract on the Doctrine of Motion that arises from the impact between two bodies, illustrated by experiments. And a third is, The History of the Seasons, as to the temperature, weather, productions, diseases, &c, &c. For which purpose he contrived many curious machines, several of which kept their own registers, tracing out the lines of variations, so that a person might know what changes the weather had undergone in his absence: as windgages, thermometers, barometers, hygrometers, raingages, &c.—He made also great additions to the new discoveries on pendulums; and among other things shewed, that there may be produced a natural standard for measure from the pendulum for common use.—He invented many ways to make astronomical observations more easy and accurate: He sitted and hung quadrants, sextants, and radii more commodiously than formerly: he made two telescopes to open with a joint like a sector, by which observers may infallibly take a distance to half minutes, &c. He made many sorts of retes, screws, and other devices, for improving telescopes to take small distances, and apparent diameters, to seconds: He made apertures for taking in more or less light, as the observer pleases, by opening and shutting, the better to sit glasses for crepusculine observations.—He added much to the theory of dioptrics; much to the manufacture of grinding good glasses: He attempted, and not without success, the making of glasses of other forms than spherical. He exactly measured and delineated the spheres of the humours of the eye, the proportions of which to one another were only guessed at before: a discussion shewing the reasons why we see objects erect, and that reflection conduces as much to vision as refraction. He displayed a natural and easy theory of refractions, which exactly answered every experiment. He fully demonstrated all dioptrics in a few propositions, shewing not only, as in Kepler's Dioptrics, the common properties of glasses, but the proportions by which the individual rays cut the axis, and each other, upon which the charges of the telescopes, or the proportion of the eye-glasses and apertures, are demonstrably discovered.—He made constant observations on Saturn, and a true theory of that planet, before the printed discourse by Huygens, on that subject, appeared.—He made maps of the Pleiades and other telescopic stars: and proposed methods to determine the great question as to the earth's motion or rest, by the small stars about the pole to be seen in large telescopes—In navigation he made many improvements. He sramed a magnetical terella, which he placed in the midst of a plane board with a hole, into which the terella is half immersed, till it be like a globe with the poles in the horizon: the plane is then dusted over with steel filings from a sieve: the dust, by the magnetical virtue, becomes immediately figured into furrows that bend like a sort of helix, proceeding as it were out at one pole, and returning in by the other; the whole plane becoming figured like the circles of a planisphere.—It being a question in his time among the problems of navigation, to what mechanical powers sailing against the wind was reducible; he shewed it to be a wedge: and he demonstrated, how a transient sorce upon an oblique plane would cause the motion of the plane against the first mover: and he made an instrument mechanically producing the same effect, and shewed the reason of sailing on all winds. The geometrical mechanism of rowing, he shewed to be a lever on a moving or cedent fulcrum: for this end, he made instruments and experiments, to find the resistance to motion in a liquid medium; with other things that are the necessary elements for laying down the geometry of sailing, swimming, rowing, flying, and constructing of ships—He invented a very speedy and curious way of etching. He started many things towards the emendation of water-works. He likewise made some instruments for respiration, and for straining the breath from fuliginous vapours, to try whether the same breath, so purisied, will serve again.—He was the first inventor of drawing pictures by microscopical glasses. He found out perpetual, or at least longlived lamps, for keeping a perpetual regular heat, in order to various uses, as hatching of eggs and insects, production of plants, chemical preparations, imitating nature in producing fossils and minerals, keeping the motion of watches equal, for the longitude and astronomical uses.—He was the first author of the anatomical experiment of injecting liquor into the veins of animals. By this operation, divers creatures were immediately purged, vomited, intoxicated, killed, or revived, according to the quality of the liquor injected. Hence arose many other new experiments, particularly that of transfusing blood, which has been prosecuted in sundry curious instances. This is a short account of the principal discoveries which Dr. Wren presented, or suggested, to the Royal Society, or were improved by him.

As to his architectural works: It has before been | observed that he had been sent for to assist Sir John Denham. In 1665 he travelled into France, to examine the most beautiful edifices and curious mechanical works there, when he made many useful observations. Upon his return home, he was appointed architect, and one of the commissioners for repairing St. Paul's cathedral. Within a few days after the fire of London, 1666, he drew a plan for a new city, and presented it to the king; but it was not approved of by the parliament. In this model, the chief streets were to cross each other at right angles, with lesser streets between them; the churches, public buildings, &c, so disposed as not to interfere with the streets, and four piazzas placed at proper distances.—Upon the death of Sir John Denham, in 1668, he succeeded him in the office of surveyorgeneral of the king's works; and from this time he had the direction of a great many public edifices, by which he acquired the highest reputation. He built the magnificent theatre at Oxford, St. Paul's cathedral, the Monument, the modern part of Hampton Court, Chelsea-college, one of the wings of Greenwich hospital, the churches of St. Stephen Walbrook, and St. Mary-le-bow, with upwards of 60 other churches and public works, which that dreadful fire made necessary. In the management of which business, he was assisted in the measurements, and laying out of private property, by the ingenious Dr. Robert Hook. The variety of business in which he was by this means engaged, requiring his constant attendance and concern, he resigned his Savilian professorship at Oxford in 1673; and the year following he received from the king the honour of knighthood.—He was one of the commissioners who, on the motion of Sir Jonas Moore, surveyor-general of the ordnance, had been appointed to find out a proper place for erecting an observatory; and he proposed Greenwich, which was approved of; the foundation stone of which was laid the 10th of August 1675, and the building was presently finished under the direction of Sir Jonas, with the advice and assistance of Sir Christopher.

In 1680 he was chosen president of the Royal Society; afterwards appointed architect and commissioner of Chelsea-college; and in 1684, principal officer or comptroller of the works in Windsor-castle. Sir Christopher sat twice in Parliament, as a representative for two different boroughs. While he continued surveyor-general, his residence was in Scotland-yard; but after his removal from that office, in 1718, he lived in St. James's-street, Westminster. He died the 25th of February 1723, at 91 years of age; and he was interred with great solemnity in St. Paul's cathedral, in the vault under the south wing of the choir, near the <*>ast end.

As to his person, Sir Christopher Wren was of a low stature, and thin frame of body; but by temperance and skilful management he enjoyed a good state of health, to a very unusual length of life. He was modest, devout, strictly virtuous, and very communicative of his knowledge. Besides his peculiar eminence as an architect, his learning and knowledge were very extensive in all the arts and sciences, and especially in the mathematics.

Sir Christopher never printed any thing himself, but several of his works have been published by others: some in the Philosophical Transactions, and some by Dr. Wallis and other friends.—His posthumous works and draughts were published by his son.