^{2})=2 log(a), and log(√a)=1/2 log(a) (remember that taking a square root is the same as raising that number to the power 1/2). Napier tabulated thousands of logarithms and developed a simple device, called a slide rule, that lets you compute any logarithm with 3-digit or higher accuracy. Many mathematicians after Napier refined his tables to so many values that they fill entire books. So if you wanted to compute, say, √2 you would use the fact that log(√2)= (1/2) log(2). You'd look up the value of log(2) in the table, get 0.3010 (usually they tabulated the decadic, or base-10, logarithms), divide it by 2, get 0.1505, then look up which log would give you 0.1505, and it would be 1.414, which is √2 rounded to 4 significant digits. It's really neat!

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