Richard Delamain


Born: 1600 in London, England
Died: 1644

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Richard Delamain was a joiner by trade. He studied mathematics at Gresham College London. After this he remained in London becoming a private tutor of mathematics.

Delamain became mathematics tutor to Charles I, who was king of Great Britain and Ireland (1625-49). Delamain was the same age as the king he tutored, both being born in 1600. He received £40 per year in this position.

Delamain became a student of Oughtred and they were great friends at first. Oughtred wrote

As I did to Delamain, and to some others ... I freely gave ... my helpe and instruction. ... But Delamain was already corrupted with doring upon instruments, and quite lost from ever being made an artist.

They had a bitter dispute over the invention of a circular slide rule. Oughtred described the slide rule in 1622 but the circular slide rule was not described by him until 1632. Delamain described a circular slide rule in a 32 page pamphlet Grammelogia which was sent to the King in 1629 and published the following year. His fame as a mathematician rests on this work.

Delamain also published The Making, Description, and Use of . . . a Horizontal Quadrant (1631) which Oughtred claimed consisted of ideas stolen from him.

Delamain argued with Oughtred, not only concerning the invention of the circular slide rule but also as regards the use of instruments in teaching mathematics. Oughtred, as an attack on Delamain, claimed that

.. the true way of art is not by instruments, but by demonstration: and that it is a preposterous course of vulgar teachers to begin with instruments.

Delamain replied

... theory is as the mother that produceth the daughter, the very sinewes and life of practise, the excellencie and highest degree of true mathematical knowledge: but for those that would make but a step as it were into that kind of learning, whose onely desire is expedition and facilitie ... all are best effected with instrument rather than with tedious regular demonstrations...

If we think of modern instruments as computers then one would have to say that Delamain's views have a ring of realism in today's world which are somewhat lacking in Oughtred's high ideals.

As well as mathematical instruments Delamain also made sundials.

He died in the Civil war some time before 1645 about five years before Charles I was executed.

Article by: J J O'Connor and E F Robertson


List of References (4 books/articles)

Mathematicians born in the same country


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  1. The Galileo Project

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