Earliest Known Uses of Some of the Words of Mathematics (R) Last revision: Aug. 13, 2005 RADIAN. According to Cajori (1919, page 484): An isolated matter of interest is the origin of the term 'radian', used with trigonometric functions. It first appeared in print on June 5, 1873, in examination questions set by James Thomson at Queen's College, Belfast. James Thomson was a brother of Lord Kelvin. He used the term as early as 1871, while in 1869 Thomas Muir, then of St. Andrew's University, hesitated between 'rad', 'radial' and 'radian'. In 1874, T. Muir adopted 'radian' after a consultation with James Thomson. In a footnote, Cajori gives a reference to Nature, In a letter appearing in the April 7, 1910, Nature, Thomas Muir wrote: "I wrote to him [i.e., to Alexander J. Ellis, in 1874], and he agreed at once for the form 'radian,' on the ground that it could be viewed as a contraction for 'radial angle'..." In a letter appearing in the June 16, 1910, Nature, James Thomson wrote: "I shall be very pleased to send Dr. Muir a copy of my father's examination questions of June, 1873, containing the word 'radian.' ...It thus appears that 'radian' was thought of independently by Dr. Muir and my father, and, what is really more important than the exact form of the name, they both independently thought of the necessity of giving a name to the unit-angle" [Dave Cohen]. A post on the Internet indicated that Thomas Muir (1844-1934) claimed to have coined the term in 1869, and that Muir and Ellis proposed the term as a contraction of "radial angle" in 1874. A reference given was: Michael Cooper, "Who named the radian?" | |
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