Baker, Thomas

, an eminent mathematician in the seventeenth century, the son of James Baker of Ikon in Somersetshire, steward to the family of the Strangways of Dorsetshire, was born at Ikon about the year 1625, and entered in Magdalen-hall, Oxon, in the beginning of the year 1640. In April 1645, he was elected scholar of Wadham college and did some little servicb to king Charles I. within the garrison of Oxford. He was admitted bachelor of arts, April 10, 1647, but left the university without completing that degree by determination. Afterwards he became vicar of Bishop’s-Nymmet in Devonshire, where he lived many years in studious retirement, applying chiefly to the study of the mathematics, in which he made very great progress. But in his obscure neighbourhood, he was neither known, nor sufficiently valued for his skill in that useful branch of knowledge, till he published his famous book. A little before his death, the members of the royal society sent him some mathematical queries to which he returned so satisfactory an answer, that they gave him a medal with an inscription full of honour and respect. He died at Bishop’s-Nymmet aforementioned, on the 5th of June 1690, and was buried in his own church. His book was entitled “The Geometrical Key, or the Gate of Equations unlocked, or a new Discovery of the construction of all Equations, howsoever affected, not exceeding the fourth degree, viz. of Linears, Quadratics, Cubics, Biquadratics, and the rinding of all their roots, as well false as true, without the use of Mesolahe, Trisection of Angles, without | Reduction, Depression, or any other previous Preparations of Equations, by a Circle, and any (and that one only) Farabole, &c.” London, 1684, 4to, in Latin and English. In the Philosophical Transactions, it is observed, that the author, in order to free us of the trouble of preparing the equation by taking away the second term, shews us how to construct all affected equations, not exceeding the fourth power, by the intersection of a circle and parabola, without omission or change of any terms. And a circle and a parabola being the most simple, it follows, that the way which our author has chosen is the best. In the book (to render it intelligible even to those who have read no conies), the author shews, how a parabola arises from the section of a cone, then bow to describe it in piano, and from that construction demonstrates, that the squares of the ordinates are one to another, as the correspondent sagitta or intercepted diameters then he shews, that if a line be inscribed in a parabola perpendicular to any diameter, a rectangle made of the segments of the inscript, will be equal to a rectangle rr.ade of the intercepted diameter and parameter of the axis. From this last propriety our author deduces the universality of his central rule for the solution of ai! 2 biquadratic and cubic equations, however affected or varied in terms or signs. After the synthesis the author shews the analysis or method, by which he found this rule which, in the opinion of Dr. R. Plot (who was then secretary to the royal society) is so good, that nothing can be expected more easy, simple, or universal. ¹