Gregory , family , scientists

David Gregory of Kinnairdie (1627-1720), inventor: apprenticed by his father to a mercantile house in Holland; returned in 1655, and succeeded to the estate of Kinnairdie on the death of an older brother; highly regarded in medicine, having a large gratuitous practice both among the poor, and people of standing; first man in Aberdeenshire to possess a barometer, and his weather forecasts exposed him to suspicions of witchcraft; moved to Aberdeen and investigated artillery; with the help of an Aberdeen watchmaker constructed an improved model of a cannon, forwarding it to his eldest son David, and to Sir Isaac Newton, who held it was 'for the diabolical purpose of increasing carnage', and who urged him to break it up.

David Gregorie (1661-1708), astronomer: son of David Gregory (1627-1720); Professor of Mathematics at Edinburgh University in 1683; first professor to lecture publicly on Newtonian philosophy, and enthusiastic promoter of Newton's 'Principia'; in 1691 went to Oxford where he was introduced to Newton, who became an intimate friend and who with John Flamsteed influenced his appointment as Savilian Professor of Astronomy in Oxford; Fellow of the Royal Society, 1692; his principal work Astronomiae Physicae et Geometricae Elementa in 1702 was the first text book composed on gravitational principles and remodelling astronomy in conformity with physical theory; approved by Newton, who had included in it his lunar theory, and for which he wrote a preface; Gregory was a skilful mathematician who left manuscript treatises on fluxions, trigonometry, mechanics and hydrostatics, and who was also known for his printing in 1703 of all the writings attributed, with any show of authority, to Euclid.

James Gregory (1638-1675), mathematician: younger brother of David Gregory (1627-1708); his scientific talent was discovered and encouraged by his brother, and in 1673 at the age of 24 he published his Optica Promota, containing the first feasible description of a reflecting telescope, his invention of it dating from 1661, and inspiring Newton to make his own reflecting telescope; studied mathematics in Padua, 1664-1667, publishing Vera Circuli et Hyperbolae Quadratura in 1667, showing how to find the areas of the circle, elipse, and hyperbole by means of converging series, and applying the same new method to calculation of logarithms; Fellow of the Royal Society, 1668; friendly debate with Newton, 1672-1673, as to merits of their respective telescopes; from 1674 first exclusively mathematical professor at Edinburgh.

Charles Gregory was one of the 32 children of David Gregory (1627-1720) and brother of the second David Gregory (1661-1708).