responsible for the publication in 1614 of the first tables of logarithms. His mathematical interests, pursued in spare time from church and state affairs, were in spherical trigonometry and, notably, in computation. His logarithms were defined geometrically rather than in terms of a base. He defined the logarithm of x to be y, with

As ${\left(1-{10}^{-7}\right)}^{{10}^7}\approx 1/e$, Napier was effectively using base 1/e for his logarithms.