BRIGGS, HENRY (1561-163o ) , English mathematician, was born at Warley Wood, near Halifax, in Yorkshire. He gradu ated at St. John's college, Cambridge, in 1581, and obtained a fellowship in 1588. In 1592 he was made reader of the physical lecture founded by Dr. Thomas Linacre, and in 1596 first profes sor of geometry in Gresham House (afterwards College), Lon don. In his lectures at Gresham House he proposed the alteration of the scale of logarithms from the hyperbolic form which John Napier had given them, to that in which unity is assumed as the logarithm of the ratio of ten to one. In conferences with Napier the alteration proposed by Briggs was agreed upon; and on his return from his second visit to Edinburgh in he accordingly published the first chiliad of his logarithms. (See NAPIER, JOHN.) In 1619 he was appointed Savilian professor of geometry at Oxford. 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 his Arithmetica Loga rithmica, in folio, a work containing the logarithms of 30,000 natural numbers to 14 places of figures besides the index. He also completed a table of logarithmic sines and tangents for the hundredth part of every degree to 14 places of figures besides the index with a table of natural sines to 15 places, and tangents and secants for the same to ten places; all of which were printed at Gouda in 1631 and published in London in 1633 under the title of Trigonometria Britannica (see TABLE, MATHEMATICAL). Briggs died on Jan. 26, 1630.
Other works are: A Table to find the Height of the Pole, the Magnetical Declination being given (1602) ; "Tables for the Improve ment of Navigation," printed in the second edition of Edward Wright's treatise entitled Certain Errors in Navigation detected and corrected (161o) ; A Description of an Instrumental Table to find the part proportional, devised by Mr. Edward Wright (1616 and 1618) ; Euclidis Elementorum VI. libri priores (162o) ; A Treatise on the North-West Passage to the South Sea (1622), reprinted in Purchas's Pilgrims, vol. iii. p. 852 ; Mathematica ab Antiquis minus cognita. Some other works, as his Commentaries on the Geometry of Peter Remus, and Remarks on the Treatise of Longomontanus respecting the Quadrature of the Circle, have not been published.