"The industrial revolution was well under way before the steam-engine came into general use... Only two prime-movers—the water-wheel and the —were widely available, and with very few exceptions these yielded no more than 10 h.p. and often less. ...In the late eighteenth and in the nineteenth century the efficiency of the water-wheel was considerably improved by theoretical and practical studies made by ... Among the numerous engineers influenced by his work was Joseph Glynn... Up to 1800 there were no steam-engines developing more than about 50 h.p. ...as late as 1835 the average power of steam-engines in Britain was only 15 h.p."