that he could distinguish the fifth part of a note; could judge of the size of a room by the same sense; and, even he walked over a pavement, in courts

or piazzas, which reflected a sound, and was afterwards conducted thither again, could tell in what part of it he stood, merely by the note it sounded.

BROOK, son of John Taylor, Esq. of Bifrons House, in Kent, was born at Edmonton, in 1685. After having made considerable progress in the languages and mathematics, under a private tutor, he was, in 1701, entered a fellow-commoner of St. John's College, Cambridge. Pursuing his mathematical studies with ardour and success, he wrote, in 1708, his Treatise on the Centre of Oscillation, which was subsequently published in the Philosophical Transactions; and, in the following year, he graduated B.A. In 1712, he was elected a fellow of the Royal Society, having previously given a solution of Kepler's famous problem, in the course of a correspondence between himself and Professor Keill. In 1714, he was elected secretary of the Royal Society, whose reputation he considerably augmented by his knowledge of those branches of science, which, at this time, engaged their particular attention, and involved them in controversies with several foreign academies. In the same year, he took his degree of LL.D.; and, in 1715, held a correspondence with Count Raymond de Montmort, respecting the tenets of Malebranche, in which he displayed so much ability, as to come in for a share of praise in the éloge pronounced before the French Academy, on the death of that eminent mathematician. Whilst visiting Paris, in 1716, the greatest attention and respect were paid to him by the most distinguished characters, and, among others, he was introduced to Lord Bolingbroke, Count de Caylus, and the celebrated Bossuet.

Shortly after his return to London, in February, 1717, he composed, and communicated to the Royal Society, three admirable treatises, entitled, respectively, An Attempt towards an Improvement of the Method of Approximating in the Extraction of Roots in Equations in Numbers; A Solution of

Demoivre's Fifteenth Problem, with the assistance of Combinations and Infinite Series; and A Solution of the Problem of G. G. Leibnitz, proposed to the English. The injury his health had received in consequence of his intense study, compelled him to make a second tour to the continent, where he resided, for some months, at Aix-la-Chapelle. On his return, he devoted himself chiefly to the completion of a treatise, which his taste for drawing had induced him to write, on Linear Perspective, a work in much reputation with artists, as improved and published by Mr. Kirby, under the title of Brook Taylor's Perspective made Easy. The original was characterized, by Joseph Bernouilli, in the Acta of Leipsic, as "abstruse to all, and unintelligible to artists;" an assertion which produced an irreconcileable quarrel between him and the subject of our memoir. It must be confessed, that the work is ill calculated for practitioners, though, unquestionably of great merit, and one which, among mathematicians, is deservedly held in high repute. Dr. Taylor's answer to Bernouilli's objections, may be seen in the Thirtieth Volume of the Philosophical Transactions, to which he communicated his last paper that he published there, in 1721, entitled An Experiment made to ascertain the Proportion of Expansion of Liquor in the Thermometer, with regard to the degree of Heat. The author died, of a decline, which was undoubtedly hastened by his intense study, in December, 1731, in the forty-sixth year of his age. He was twice married, and survived both his wives, the last dying in child-bed, in 1730.

Dr. Taylor appears to have been a very accomplished man, and to have extended his inquiries into a variety of subjects, besides those of which we have already spoken. Among his post

humous papers, were found detached parts of a treatise on the Jewish sacrifices, and a dissertation, of great length, on the lawfulness of eating blood. He is said to have drawn figures with extraordinary precision and beauty of pencil, and to have painted landscapes with admirable force of colour, and freedom of touch. He was also a tolerable proficient in music, and, but for his attention to other pursuits, promised to become eminent, both in the theory and practice of that art. With respect to his private character, his biographer and grandson, Sir William Young, observes: "in the best acceptation of duties relative to each situation of life in which he was engaged, his

own writings, and the writings of those who best knew him, prove him to have been the finished Christian, gentleman, and scholar."

Besides the works before-mentioned, Dr. Taylor was the author of an essay, entitled Contemplatio Philosophica, a very masterly performance, published by Sir William Young, in 1793. His other papers, in the Philosophical Transactions, are, On the Ascent of Water between Two Glass Planes; On the Motion of a Stretched String; Methodus Incrementorum ; An Account of an Experiment for the Discovery of the Law of Magnetic Attraction; and his Treatise on the Principles of Linear Perspective.

ROBERT SIMSON was born of a respectable family, in the county of Lanark, in 1687. He was educated at the University of Glasgow, where some of his relations were professors; and made great progress in every branch of learning, particularly philosophy and theology. He was accounted one of the best botanists of his years; and such was his proficiency in the oriental languages, that he was enabled to supply the place of a sick relation, who taught in that class. He studied divinity, with a view of entering into the church; but his fondness for mathematics, which, as he pursued them, increased almost to adoration, ended in his determination to devote himself to that science altogether. In 1711, his reputation caused him to be elected regius professor of mathematics in the University of Glasgow; and, about the same time, he went to London, where he formed an acquaintance with Halley, and other eminent men of that period. On his return, he applied himself to the duties of his professorship, with equal zeal for the interest of science and the advancement of his pupils.

Dr. Simson had, for some time, deeply studied the works of the ancient geometers; and, satisfied with demonstrating truth on the pure principles laid down in them, had paid, com

paratively, little attention to the modern inventions of fluxions and logarithms. With these, however, some of his posthumous papers show him to have been fully acquainted; but as the ancient geometrical analysis was but imperfectly known to many, he determined to attempt the entire recovery of this method. He first undertook the restoration of Euclid's Porisms, from the scanty and mutilated account of that work in a single passage of Pappus, a copy of whose mathematical collections had been given him by Dr. Halley, enriched with his own notes. Of this discovery, which he effected as early as 1718, he communicated an account to the Royal Society, in 1723, in which year it was printed in the Philosophical Transactions. He next engaged upon the Loci Plani of Apollonius, and completed it about 1738; though, in his own estimation, so imperfectly, that he withheld the impression for some years after it was printed, and only consented to its publication, in 1746, at the earnest solicitation of his friends. He, however, recalled as many copies as possible, for the purpose of recorrecting the work; and even then was loth to consider it a perfect restoration of Apollonius. About the same time, appeared his Treatise on Conic Sections; which, together with his restoration of

The Loci, was received with unanimous approbation, and stamped the author as one of the first and most elegant geometers of the age. Science, however, is, perhaps, less indebted to him for these works, than for his restitution of the Elements and Data of Euclid; an edition of which he published about the year 1758. This was a great deside. ratum in geometry; for although other authors had attempted a restoration of the data of Euclid, it was but partial, in comparison with the ample restitution effected by Dr. Simson. Few incidents varied the life of one so much devoted to study as the subject of our memoir, who died, after a long course of almost uninterrupted health, in 1768, at the age of eighty-one.

Dr. Simson was tall and dignified in stature, with a fine expressive countenance, and a gracefulness of manner,

which he retained till his latest moments. He was never married; and, instead of living in a commodious house, allotted to him as professor, took some chambers, spacious enough for his accommodation, with scarcely any other furniture than his small but valuable library, which he left to the university. His official servant acted as valet, footman, and bed-maker; and when he entertained company, it was at a neighbouring house, where an apartment was specially kept for himself and his guests.

Besides the works before-mentioned, he restored The Sectio Determinata of Apollonius, which was published after his death, along with the work on the Porisms of Euclid, at the expense of the Earl of Stanhope. A very interesting account of Dr. Simson's life and writings has been published by Dr. Trail, in one quarto volume.

THIS gentleman, one of the most distinguished promoters of scientific knowledge, of his day, was the son of a barrister, and born in Westminster, in the year 1690. He received the first part of his education under the private tuition of Mr. Cappel, nephew of the celebrated Lewis Cappel. In his seventeenth year, he was entered of Clare Hall, Cambridge, where he distinguished himself in his pursuit of mathematical and philosophical studies. As early as his twenty-third year, he was elected a fellow of the Royal Society, of which Sir Isaac Newton was then at the head. The subject of our memoir was frequently elected into the council of the Society; and, in 1723, he was nominated, by Sir Isaac, who entertained a high opinion of his abilities, one of the vice-presidents. On the death of Newton, in 1727, Mr. Folkes was a candidate for the presidentship, which was, however, obtained by Sir Hans Sloane, but he still continued a member of the council, and was re-appointed vicepresident, in 1733.

He passed the greater part of this and the two following years, in Italy, where he devoted the principal portion

of his time to the study of classical antiquities. The weight and value of ancient coins, formed the chief object of his researches, with a view to which, he inspected various cabinets; and, on his return, he presented the Society of Antiquaries, of which he was a member, a dissertation on the subject. Before the same body, he also read a paper upon the measurements of Trajan's and Antonine's pillars; and, at their request, subsequently printed a table of all the English gold coins with which he had presented them. Among other papers, which he communicated to the Royal Society, were, Remarks on the Standard Measure, preserved in the capitol of Rome; and a Model of an Ancient Sphere, preserved in the Farnesian Palace: a draught of the latter was published in Dr. Bentley's edition of Manilius.

In 1739, Mr. Folkes visited Paris, where he was treated with marked respect by all the literary and scientific savans of that metropolis. On the resignation of Sir Hans Sloane, in 1741, he was chosen president of the Royal Society; and shortly afterwards was enrolled, in the room of Dr. Halley, as

one of the eight foreign members of the Royal Academy of Sciences at Paris. In 1745, appeared his valuable work, entitled A Table of English Silver Coins, from the Norman Conquest to the Present Time, with their weights, intrinsic values, and some remarks upon the several pieces. At the same time, he reprinted his Table of Gold Coins, and intended to have illustrated both with plates, but his death prevented their publication by himself. They were subsequently purchased, and published, in a new edition of the work, by the Antiquarian Society. Of this body, Mr. Folkes became president, and he was also honoured with the degree of LL.D., by both universities, some time previous to his decease, which took place in 1754. cause of it was palsy, repeated attacks

The

of which, had, a short time previous to his death, deprived him of the use of his mental faculties.

Mr. Folkes appears to have attained a very unusual degree of eminence in the scientific world, considering that he benefitted it by no new discovery. He was principally skilled in the elucidation of the intrinsic subjects of weights, coins, and measures; but was an active promoter of every species of curious and useful knowledge. He left a large and valuable cabinet and library, which was sold by public auction. Besides the works before-mentioned, he communicated a variety of papers to the Philosophical Transactions, displaying considerable elegance of style and extent of information. His private character is said to have been extremely estimable.

THIS eminent astronomer was born at Shireborn, in Gloucestershire, in the year 1692. His life, devoted almost entirely to science, affords but few incidents for the biographer. He received the first part of his education at a boarding-school in Northleach, and being intended for the church, was sent to Baliol College, Oxford, of which he was admitted a commoner, on the 15th of March, 1710. He graduated B. A. in 1714, M. A. in 1717, and received ordination as deacon, from the Bishop of London, on the 24th of May, 1719. Shortly afterwards, he obtained priest's orders from the Bishop of Hereford, who made him his chaplain, and, at the same time, presented him to the vicarage of Bridstow, in Herefordshire.

Bradley would, in all probability, have risen to eminence in the church, by his own talents, and the patronage of his friends, had not his early predilection for the science of astronomy given his mind a different turn. To enable him to pursue this uninterruptedly, Mr. Molyneux, then secretary to the Prince of Wales, and distinguished for his successful cultivation of optics and astronomy, procured for him the sinecure rectory of Landewy Welfry, in Pem

brokeshire, to which he was admitted a few months after he had taken priest's orders.

It was during his residence at Wanstead, in Essex, with his uncle, Dr. Pound, to whom he sometimes officiated as curate, that Bradley commenced those observations, which afterwards conducted him to some of the finest discoveries of which the science of astronomy can boast. He soon began to attract the notice of some of the most eminent members of the Royal Society; and Lord Macclesfield, Sir Isaac Newton, Dr. Halley, and others, were amongst those who particularly encouraged him.

On the 31st of October, 1721, he was appointed to succeed Dr. Keill, as Savilian professor of astronomy; and, on his acceptance of this office, resigned his livings, both of Bridstow and Landewy. In 1724, he communicated to the Royal Society his observations on the comet of 1723; and, in 1726, his observations on some eclipses of Jupiter's satellites; neither papers possessing any other merit than the accuracy with which the observations were made.

He was, however, not long in making a very important discovery, that of