Born 1550 in Merchiston, near Edinburgh; died there Apr. 4, 1617. Scottish mathematician; inventor of logarithms.
Napier studied at the University of Edinburgh. He had mastered the fundamental concepts of logarithms before 1594; however, his Mirifici logarithmorum canonis descriptio . .. (Description of the Marvelous Canon of Logarithms), in which he set forth this knowledge, was published in 1614. This work contained a definition of logarithms; an explanation of their properties; tables of the logarithms of sines, cosines, and tangents; and applications of logarithms to spherical trigonometry. In Mirifici logarithmorum canonis constructio . .. (Construction of the Marvelous Canon of Logarithms), published 1619, Napier set forth the principles for calculating the tables. The kinematic definition of a logarithm given by Napier is essentially equivalent to the definition of a logarithmic function in terms of a differential equation. Napier also discovered a number of formulas for solving spherical triangles that can be conveniently given in logarithmic form.