The interesting question has arisen as to whether Napier was aware of the base e for his logarithms.
The answer is that he knew of 1/e as ( 1- 0.9999999) to the power of 10 million which would be multiplied
by his other powers such as 0.693147 to arrive at 1/2. I have recently come to the conclusion that there
is far more to the historical origin of logarithms than most mathematicians suspect. Madhava of Sangamagrama
(1425) applied calculus to tangent formulae which could have inspired Napier to follow a similar path to arrive
at the basic formula for log2.