Consider two sequences generated by ",,+ i Mi"„<hn)hn*\ M'i"„+X,b„), where the a„ and b„ are positive and M and M' are means. The paper discusses the nine processes which arise by restricting the choice of M and M' to the arithmetic, geometric and harmonic means, one case being that used by Archimedes to estimate it. Most of the paper is devoted to the arithmetic-harmonic mean, whose limit is e...