John Speidell
John Speidell (fl. 1600–1634) was an English mathematician. He is known for his early work on the calculation of logarithms.
Speidell was a mathematics teacher in London[1][2] and one of the early followers of the work John Napier had previously done on natural logarithms.[3] In 1619 Speidell published a table entitled "New Logarithmes" in which he calculated the natural logarithms of sines, tangents, and secants.[4][5]
He then diverged from Napier's methods in order to ensure all of the logarithms were positive.[6] A new edition of "New Logarithmes" was published in 1622 and contained an appendix with the natural logarithms of all numbers 1-1000.[7]
Along with William Oughtred and Richard Norwood, Speidell helped push toward the abbreviations of trigonometric functions.[7]
Speidel published a number of work about mathematics, including An Arithmeticall Extraction in 1628.[8]
References
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