"One of the greatest curiosities of the history of science that Napier constructed logarithms before exponents were used. To be sure, Stifel and Stevin made some attempts to denote powers by indices, but this notation was not generally known,—not even to T. Harriot, whose algebra appeared long after Napier's death. That logarithms flow naturally from the exponential symbol was not observed until much later. ...While F. Vieta represented A^3 by "A cubus" and Stevin x^3 by a figure 3 within a small circle [around it], Descartes wrote a^3."