The base is flexible. A slide rule is fundamentally just a set of adding sticks where you perform addition and subtraction in "log space". As long as you convert back out of the log scale it doesn't matter what the base was.
My primary use for logarithms today is verifying how many bits an intermediate calculation is going to need on a calculator without base-2 logs. The base conversion algorithm doesn't care what intermediate base you use as long as they match: bits ~= log2(x) == log10(x) / log10(2) == ln(x) / ln(2).
My primary use for logarithms today is verifying how many bits an intermediate calculation is going to need on a calculator without base-2 logs. The base conversion algorithm doesn't care what intermediate base you use as long as they match: bits ~= log2(x) == log10(x) / log10(2) == ln(x) / ln(2).