# 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

1. ^ John Aubrey; Andrew Clark (1898). 'Brief Lives': I-Y. At the Clarendon Press. pp. 230–231.
2. ^ Kerry Downes; John F. Bold; Edward Chaney (1993). English Architecture Public & Private: Essays for Kerry Downes. A&C Black. pp. 28–. ISBN 978-1-85285-095-1.
3. ^ E. W. Hobson (29 March 2012). John Napier and the Invention of Logarithms, 1614: A Lecture by E.W. Hobson. Cambridge University Press. pp. 43–. ISBN 978-1-107-62450-4.
4. ^ Charles Hutton (1785). Mathematical Tables, Containing Common, Hyperbolic and Logistic Logarithms, Also Sines Tangents, Secants and Versed Sines, Both Natural and Logarithmic. Robinson and Baldwin. pp. 30–.
5. ^ Florian Cajori (26 September 2013). A History of Mathematical Notations. Courier Corporation. pp. 1–. ISBN 978-0-486-16116-7.
6. ^ Sir David Brewster (1819). Second American edition of the new Edinburgh encyclopædia. Published by Samuel Whiting and John L. Tiffany; also, by N. Whiting, New-Haven; A. Seward, Utica; S. Parker, Philadelphia; Wm. Snodgrass, Natchez; and I. Clizbe, New-Orleans 1819. pp. 112–.
7. ^ a b Florian Cajori (1893). A History of Mathematics. Macmillan & Company. pp. 165–.
8. ^ Augustus De Morgan (1847). Arithmetical Books from the Invention of Printing to the Present Time: Being Brief Notices of a Large Number of Works Drawn Up from Actual Inspection. Taylor and Walton. pp. 37–.