SAUNDERSON, (Da. Ntenor...a,) in biography, an illustrious professor of mathematics in the University of Cam bridge, and a fellow of the Royal Society, was born at Thurlston, in Yorkshire, in 1682 When he was but twelve months old, he lost not only his eye-sight, but his very eye-balls, by the small-pox ; so that he could retain no more ideas of vi sion than if he had been born blind. At an early age, however, being of very promising parts, he was sent to the free school at Penniston, and there laid the foundation of that knowledge of the Greek and Latin languages, which he af terwards improved so fir, by his own application to the classic authors, as to hear the works of Euclid, Archimedes, and Diophantes, read in their original flreek.
Having acquired a grammatical educa tion, his father, who was in the excise, instructed him in the common rules of arithmetic. And here it was that his ex cellent mathematical genius first appear ed; for he very soon became able to work the common questions, to make very long calculations by the strength of his memory, and to form new rules to himself, for the better resolving of such questions as are often proposed to learn ers as trials of skill.
At the age of eighteen our author was introduced to the acquaintance of Richard West, of Underbank, Esq., a lover of mathematics, who, observing Mr. Saun derson's uncommon capacity, took the pains to instruct him in the principles of algebra and geometry, and gave him every encouragement in his power to the prosecution of these studies. Soon after this he became acquainted also with Dr. Nettleton, who took the same pains with him. And it was to these two gentle men that Mr. Saunderson owed his first instruction in the mathematical sciences ; they furnished him with books, and often read and expounded them to him. But be soon surpassed his masters, and be came fitter to teach, than to learn any thing from them.
His hither, otherwise burdened with a numerous family, finding a difficulty in supporting him, his friends began to think of providing both for his education and maintenance. His own inclination led him strongly to Cambridge, and it was at length determined he should try his for tune there, not as a scholar, but as a mos. ter ; or, if this design should not suc ceed, they promised themselves success in opening a school for him at London.
Accordingly he went to Cambridge in 1707, being then twenty-five years of age, and his fame in a short time filled the University. Newton's Principia, Optics, and Universal Arithmetic, were the foun dations of his lectures, and afforded him a noble field for the display of his genius ; and great numbers came to hear a blind man give lectures on optics, discourse on the nature of light and colours, explain the theory of vision, the effect of glasses, the phenomenon of the rainbow, and other objects of sight.
As he instructed youth in the princi• plea of the Newtonian philosophy, he soon became acquainted with its incom parable author, though he had several years before left the University ; and fre quently conversed with him on the most difficult parts of his works : he also held a friendly communication with the other eminent mathematicians of the age, as Halley, Cotes, De Moivre, &c.
Mr. Whiston was all this time in the ma thematical professor's chair, and read lec tures in the manner proposed by Mr. Saun derson on his settling at Cambridge ; so that an attempt of this kind looked like an encroachment on the privilege of his office ; but as a good natured man, and. an encourager of learning, he readily consented to the application of friends made in behalf of so uncommon a per son.
Upon the removal of Mr. Whiston from his professorship, Mr. Sanderson's merit was thought so much superior to that of any other competitor, that an extraordi. nary step was taken in his favour, to qualify him with a degree, which the statute requires : in consequence he was chosen, in 1711, Mr. Whiston's successor in the Lucasian professorship of mathema tics ; Sir Isaac Newton interesting him self greatly in his favour. His first per formance, after he was seated in the chair, was an inaugural speech made in very elegant Latin, and a style truly Cice roman ; for be was very well versed in the writings of Tully, who was his fa vourite in prose, as Virgil and Horace were in verse. From this time he applied himself closely to the reading of lectures, and gave up his whole time to his pupils. He continued to reside among the gen tlemen of Christ College till the year 1723, when he took a house in Cam bridge, and soon after married a daughter of Mr. Dickens, rector of Bosworth, in Cambridgeshire, by whom he had a son and a daughter.