A scientific calculator has two 'log' buttons on it. These are marked log and ln. The log key is used for calculations of the form \({\log _{10}}x\). For example, to work out that \(\log 10000 = 4\) ...

HAVING been asked to give a short course of lectures to working men, which involved an account of logarithms and the slide-rule, I felt that, although not important, there would be some advantage in ...