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 and one of the early followers of the work

John Napier John Napier of Merchiston (; 1 February 1550 – 4 April 1617), nicknamed Marvellous Merchiston, was a Scottish landowner known as a mathematician, physicist, and astronomer. He was the 8th Laird of Merchiston. His Latinized name was Ioann ...

had previously done on

natural logarithms The natural logarithm of a number is its logarithm to the base of the mathematical constant , which is an irrational and transcendental number approximately equal to . The natural logarithm of is generally written as , , or sometimes, if ...

. In 1619 Speidell published a table entitled "New Logarithmes" in which he calculated the natural logarithms of sines, tangents, and secants. He then diverged from Napier's methods in order to ensure all of the logarithms were positive. A new edition of "New Logarithmes" was published in 1622 and contained an appendix with the natural logarithms of all numbers 1-1000. Along with

William Oughtred William Oughtred ( ; 5 March 1574 – 30 June 1660), also Owtred, Uhtred, etc., was an Kingdom of England, English mathematician and Anglican ministry, Anglican clergyman.'Oughtred (William)', in P. Bayle, translated and revised by J.P. Bernar ...

and

Richard Norwood Richard Norwood (1590? – 1675) was an English mathematician, Underwater diving, diver, and surveying, surveyor. He has been called "Bermuda’s outstanding genius of the seventeenth century". Life Born about 1590, he was in 1616 sent out by the ...

, Speidell helped push toward the abbreviations of

trigonometric functions In mathematics, the trigonometric functions (also called circular functions, angle functions or goniometric functions) are real functions which relate an angle of a right-angled triangle to ratios of two side lengths. They are widely used in all ...

. Speidel published a number of work about mathematics, including ''An Arithmeticall Extraction'' in 1628. His son,

Euclid Speidell Euclid Speidell (died 1702) was an English customs official and mathematics teacher known for his writing on logarithms. Speidell published revised and expanded versions of texts by his father, John Speidell. He also published a book called ''Logar ...

, also published mathematics texts.

References

{{DEFAULTSORT:Speidell, John 16th-century births 17th-century deaths 17th-century English mathematicians