True, although the fact that all of them are pretty much equivalent does mean that there's no real reason to think of it as a logarithm with 'base' anything. A

True, although the fact that all of them are pretty much equivalent does mean that there's no real reason to think of it as a logarithm with 'base' anything. Also to the best of my knowledge there's no logarithm tables that predate Napier (1550-1617), and when you try to calculate those tables you naturally stumble upon the natural logarithm (or at least a very close approximation), as the easiest way to create a logarithm table is to start with the powers of something like 1.00000001.