John Napier, 1550-1617, Scottish mathematician. Napier came from a landed family and so was educated in France and at St. Andrews in Scotland. He studied mathematics as a hobby and he published his first logarithm tables in 1614, in the process of which he developed decimal notation. For the tables he chose the transcendental number e (approximately 2.717) as the base. These Napierian, or natural, logarithms are most relevant to exponential systems. His logarithms greatly helped Kepler in his calculations of planetary motion. As well as inventing logarithms, he also sketched ideas for what we would now recognize as the submarine and the tank.