THE name of ISAAC BARROW stands eminent among the divines and philosophers of the seventeenth century. Of the many good and great men whom it is the glory of Trinity College Cambridge to number as her fostersons, there is none more good, none perhaps, after BACON and NEWTON, more distinguished than he: and he has an especial claim to the gratitude of all members of that splendid foundation as the projector of its unequalled library, as well as a liberal benefactor in other respects.

The father of Barrow, a respectable citizen of London, was linen-draper to Charles I., and the son was naturally brought up in royalist principles. The date of his birth is variously assigned by his biographers, but the more probable account fixes it to October, 1630. It is recorded that his childhood was turbulent and quarrelsome; that he was careless of his clothes, disinclined to study, and especially addicted to fighting and promoting quarrels among his school-fellows; and of a temper altogether so unpromising, that his father

often expressed a wish, that if any of his children should die, it might be his son Isaac. He was first sent to school at the Charter House, and removed thence to Felstead in Essex. Here his disposition seemed to change: he made great progress in learning, and was entered at Trinity College in 1645, in his fifteenth year, it being then usual to send boys to college about that age. He passed his term as an under-graduate with much credit. The time and place were not favourable to the promotion of Royalists; for a royalist master had been ejected to make room for one placed there by the parliament, and the fellows were chiefly of the same political persuasion. But Barrow's good conduct and attainments won the favour of his superiors, and in 1649, the year after he took his degree, he was elected fellow. It deserves to be known, for it is honourable to both parties, that he never disguised or compromised his own principles.

His earlier studies were especially turned towards natural philosophy; and, rejecting the antiquated doctrines then taught in the schools, he selected Bacon, Galileo, and Descartes as his favourite authors. He did not commence the study of mathematics until after he had gained his fellowship, and was led to it in a very circuitous way. He was induced to read the Greek astronomers, with a view to solving the difficulties of ancient chronology; and to understand their works a thorough knowledge of geometry was indispensable. He therefore undertook the study of that science; which suited the bent of his genius so well, that he became one of the greatest proficients in it of his age. His first intention was to become a physician, and he made considerable progress in anatomy, chemistry, botany, and other sciences subservient to the profession of medicine; but he changed his mind, and determined to make divinity his chief pursuit. In 1655 he went abroad. His travels extended through

France, Italy, and the Levant, to Constantinople; and, after an absence of four years, he returned to England through Germany and Holland. During this period he lost no opportunity of prosecuting his studies; and he sent home several descriptive poems, and some letters, written in Latin, which are printed in his Opuscula, in the fourth volume of the folio edition of his works. In the voyage to Smyrna he gave a proof of the high spirit, which, purified from its childish unruliness and violence, continued to form part of his character through life. The vessel being attacked by an Algerine corsair, Barrow remained on the deck, cheerfully and vigorously fighting, until the assailant sheered off. Being asked afterwards why he did not go into the hold, and leave the defence of the ship to those whom it concerned, he replied, “It concerned no one more than myself. I would rather have died than fallen into the hands of those merciless pirates." He has described this voyage, and its eventful circumstances, in a poem contained in his Opuscula.

He entered into orders in 1659, and in the following year was made Greek Professor at Cambridge. The numerous offices to which he was appointed about this time show that his merits were generally and highly esteemed. He was chosen to be Professor of Geometry at Gresham College in 1662; and was one of the first fellows elected into the Royal Society, after the incorporation of that body by charter in 1663; in which year he was also appointed the first mathematical lecturer on the foundation of Mr. Lucas, at Cambridge. Not that he made sinecures of these responsible employments, or thought himself qualified to discharge the duties of all at once; for he resigned the Greek professorship, on being appointed Lucasian Professor, for reasons explained in his introductory oration, which is extant in the Opuscula. The Gresham

professorship he also gave up in 1664, intending thenceforth to reside at Cambridge. Finally, in 1669, he resigned the Lucasian chair to his great successor, Newton, intending to devote himself entirely to the study of divinity. Barrow received the degree of D.D. by royal mandate, in 1670; and, in 1672, was raised to the mastership of Trinity College by the King, with the compliment, "that he had given it to the best scholar in England." In that high station he distinguished himself by liberality: he remitted several allowances which his predecessors had required from the college; he set on foot the scheme for a new library, and contributed in purse, and still more by his personal exertions, to its completion. It should be remarked that his patent of appointment being drawn up, as usual, with a permission to marry, he caused that part to be struck out, conceiving it to be at variance with the statutes. He was cut off by a fever in the prime of life, May 4, 1679, aged forty-nine, during a visit to London. His remains were honourably deposited in Westminster Abbey, among the worthies of the land; and in that noble building a monument was erected to him by the contributions of his friends. (See next page.)

Of Barrow's mathematical works we must speak briefly. The earliest of them was an edition of Euclid's Elements, containing all the books, published at Cambridge in 1655, followed by an edition of the Data in 1657. His Lectiones Opticæ, the first lectures delivered on the Lucasian foundation, were printed in 1669, and attracted the following commendation from the eminent mathematician, James Gregory:-"Mr. Barrow, in his Optics, shows himself a most subtle geometer, so that I think him superior to any that ever I looked upon. I long exceedingly to see his geometrical lectures, especially because I have some notions on that subject by me.' In this work (we speak on

the authority of Montucla, part iv. viii.), Barrow has applied himself principally to discuss subjects unnoticed or insufficiently explained by preceding authors. Among these was the general problem, to determine the focus of a lens; which, except in a few cases, as where the opposite sides of the lens are similar, and