Background
Richard Delamaine was born c. 1600 in London, England.
Gresham College.
A page from Delamaines's pamphlet, Grammelogia.
A page from Delamaines's pamphlet, Grammelogia.
Delamaine was one of the original creators of the moder circular slide rule.
inventor mathematician scientist
Richard Delamaine was born c. 1600 in London, England.
Delamain was a joiner by trade, and studied mathematics at Gresham College, London.
Delamaine supported himself by teaching practical mathematics in London. Later he became mathematical tutor to King Charles I, for whom he fashioned a number of mathematical instruments. He was a pupil of William Oughtred, and in the early days of their association the two men became close friends. Unhappily this did not last, and later they quarreled violently over priority in the invention of the circular slide rule, which Delamain described in his Grammelogia, or the Mathematicall Ring.
Delamain’s fame rests mainly on this essay, a pamphlet of thirty-two pages. The manuscript was sent to the king in 1629, and the work was published the following year. The king retained Delamain’s services as tutor at a salary of £40 per annum. A few years later Delamain petitioned for an engineer’s post at a salary of £ 100 per annum. Following an interview with the king at Greenwich in 1637, he was granted a warrant for making a number of mathematical instruments.
The appearance of the Grammelogia was the signal for the beginning of the quarrel. Oughtred had invented the rectilinear slide rule as early as 1622, but his Circles of Proportion, which contained a description of the circular slide rule, was not made public until 1632 - by which time the Grammelogia had been in circulation for two years. William Forster, a friend and pupil of Oughtred, translated from the Latin and published the Circles of Proportion, the preface to which contains some ungenerous references to Delamain, who, it states, purloined the design of the circular slide rule from Oughtred. Delamain retaliated vigorously, attacking both Forster and Oughtred; the latter replied with a pamphlet, The Apologeticall Epistle, in which he refers to the "slaunderous insimulations of Richard Delamain in a Pamphlet called Grammelogia, or the Mathematical! Ring" and maintains that the latter’s horizontal quadrant is no other than the horizontal instrument he had invented thirty years earlier.
Delamain perished in the Civil War sometime before 1645. Oughtred lived until 1660, but his last years were embittered by the dispute with his former friend and pupil.
Delamaine was married and left ten children, one of whom bore his name, who is tentatively identified with the mathematician Richard Delamaine the younger.