BRIGGS, HENRY, one of the greatest mathematicians of the sixteenth century, was born in 1556 at Warley Wood, near Halifax in Yorkshire. He studied at Oxford, where in 1592 he was appointed examiner and lecturer in mathematics; soon afterwards reader of the physical lecture founded by Dr Linacre; and in 1596, first professor of geometry in Gresham College. In 1609 he contracted with Usher, afterwards archbishop of Armagh, an intimacy which was kept up chiefly by letters, two of which, written by the subject of this notice, are still extant. In one of these letters, dated in August 1610, he tells his friend he was engaged on the subject of eclipses; and in the other, dated in March 1615, he acquaints him with his being wholly employed about the noble invention of logarithms, then lately discovered, and in the improvement of which he had afterwards a large share. In his lectures at Gresham College, he proposed the alteration of the scale of logarithms, from the hyperbolic form which Napier had given them, to that in which unity is assumed as the logarithm of the ratio of ten to one; and soon afterwards he wrote to the inventor to make the same proposal to himself. In 1616 Briggs paid a visit to Napier at Edinburgh, in order to confer with that eminent person respecting the suggested change; and next year he repeated his visit for a similar purpose. During these conferences the alteration proposed by Briggs was agreed upon; and on the return of the latter from his second visit in 1617, he accordingly published the first chiliad of his logarithms. In 1619 he was appointed Savilian professor of geometry at Oxford, and resigned his professorship of Gresham College on the 25th of July 1620. Soon after his settlement at Oxford he was incorporated master of arts in that university, where he continued a laborious and studious life, employed partly in discharging the duties of his office, and partly in the computation of logarithms and in other useful works. In 1622 he published a small tract on the "North-west Passage to the South Seas, through the continent of Virginia and Hudson's Bay;" and in 1624 he printed at London his Arithmetica Logarithmica, in folio, a work containing the logarithms of thirty thousand natural numbers to fourteen places of figures besides the index. He also lived to complete a table of logarithmic sines and tangents for the hundredth part of every degree to fourteen places of figures besides the index, with a table of natural sines to fifteen places, and the tangents and secants for the same to ten places; all of which were printed at Gouda in 1631, and published in 1633, under the title of Trigonometria Britannica. In the construction of these works, the author, besides immense labour and application, displayed great powers of genius and invention; and in his investigations may be detected the germs of discoveries in mathematics which are generally considered as of later invention, namely, the binomial theorem, the differential method and construction of tables by differences, the
interpolation by differences, together with angular sections, and several other things of scarcely inferior importance. Mr Briggs terminated his laborious and useful life on the 26th of January 1630, in the seventy-fourth year of his age. Dr Smith gives him the character of being a man of great probity, a contemner of riches, and contented with his own station, preferring a studious retirement to all the splendid circumstances of life.
His works are, 1. A Table to find the Height of the Pole, the Magnetic Declination being given, London, 1602, 4to; 2. Tables for the Improvement of Navigation, printed in the second edition of Edward Wright's treatise entitled "Certain Errors in Navigation detected and corrected," London, 1610, 4to; 3. A Description of an Instrumental Table to find the part proportional, devised by Mr Edward Wright, London, 1616 and 1618, 12mo; 4. Logarithmorum Chitias prius, London, 1617, 8vo; 5. Lucubrations et Annotationes in opera posthumum J. Neperi, Edinburgh, 1619, 4to; 6. Euclidis Elementorum VI. libri priores, London, 1620, folio; 7. A Treatise on the North-west Passage to the South Sea, London, 1622, 4to, reprinted in Purchas's Pilgrims, vol. iii. p. 852; 8. Arithmetica Logarithmica, London, 1624, folio; 9. Trigonometria Britannica, Gouda, 1633, folio; 10. Two Letters to Archbishop Usher; 11. Mathematica ab Antiquis usque cognitæ; and some other works, as his Commentaries on the Geometry of Peter Ramus, and Remarks on the Treatise of Longomontanus respecting the quadrature of the Circle, which have not been published.