THOMAS, a celebrated algebraist, was born at Oxford in 1560, where he was also educated. In 1579 he completed his bachelor's degree; and, being already distinguished for his mathematical learning, was soon after recommended to Sir Walter Raleigh, as a proper person to instruct him in that science. He was accordingly received into the family of that gentleman; who, in 1585, sent him with the colony, under Sir Richard Granville, to Virginia; of which country, having remained there about a year, he afterwards published a topographical description. About the year 1588, Mr Harriot was introduced by his patron Sir Walter Raleigh, to Henry Percy earl of Northumberland, who allowed him a pension of £20 per annum. He spent many years of his life in Sion college; where he died in July 1621, of a cancer in his lip, and was buried in the church of St Christopher, where a handsome monument was erected to his memory. Anthony Wood tells us, he was a deist, and that the divines looked upon his death as an judgment. Be his religious opinions what they might, he was doubtless one of the first mathematicians of the age in which he lived, and will always be remembered as the inventor of the present improved method of algebraical calculation. His improvements in algebra were adopted by Des Cartes, and for a considerable time imposed upon the French nation as his own invention; but the theft was at last detected, and exposed by Dr Wallis, in his history of Algebra, where the reader will find our author's invention accurately specified. His works are, 1. A brief and true report of the new-found land of Virginia; of the commodities there found, and to be raised, &c. 2. Artis analyticae praxis ad aquationes algebraicas nova expe-
dita, et generali methodo resolvendas & posthumis Thomae Harrioti, &c. 3. Ephemeris chymometrica. Manuscript, in the library of Sion college. He is said to have left several other manuscripts, which are probably lost.
Dr Zach, who fully established the truth of Des Cartes having pilfered from the Artis analyticae praxis, &c. of Harriot, and given it to the world as his own, speaks thus of our celebrated mathematician and algebraist: "It is remarkable, that the fame and the honour of this truly great man, were constantly attacked by the French mathematicians, who could not endure that Harriot should in any way diminish the fame of their Vieta and Des Cartes, especially the latter, who was openly accused of plagiarism from our author.
"Des Cartes published his Geometry six years after Harriot's work appeared, viz. in the year 1637. Sir Charles Cavendish, then ambassador at the French court, observed to the famous geometrician Roverval, that these improvements in analysis had been already made these six years in England; and showed him afterwards Harriot's Artis Analyticae Praxis: which, as Roverval was looking over, at every page he cried out, yes! yes! he has seen it! Des Cartes had also been in England before Harriot's death, and had heard of his new improvements and inventions in analysis.
"I found likewise (says Dr Zach) among the papers of Harriot a large set of observations on the satellites of Jupiter, with drawings of them, their positions, and calculations of their revolutions and periods. His first observation of these discovered satellites, I find to be of January 16. 1610, and they go till February 26. 1612. Galileo pretends to have discovered them January 7. 1610; so that it is not improbable that Harriot was likewise the first discoverer of these attendants of Jupiter."