optics and astronomy; his ill health induced him to pry into the
secrets of physiology; and his solitary walks through the country
attracted him to the study of botany and history. While carrying
on the business of a mathematical-instrument maker, he received an
order to build an organ; and, though without an ear for music, he
undertook the study of harmonics, and successfully constructed the
instrument. And, in like manner, when the little model of
Newcomen's steam-engine, belonging to the University of Glasgow,
was placed in his hands to repair, he forthwith set himself to
learn all that was then known about heat, evaporation, and
condensation,--at the same time plodding his way in mechanics and
the science of construction,--the results of which he at length
embodied in his condensing steam-engine.

For ten years he went on contriving and inventing--with little hope
to cheer him, and with few friends to encourage him. He went on,
meanwhile, earning bread for his family by making and selling
quadrants, making and mending fiddles, flutes, and musical
instruments; measuring mason-work, surveying roads, superintending
the construction of canals, or doing anything that turned up, and
offered a prospect of honest gain. At length, Watt found a fit
partner in another eminent leader of industry--Matthew Boulton, of
Birmingham; a skilful, energetic, and far-seeing man, who
vigorously undertook the enterprise of introducing the condensing-
engine into general use as a working power; and the success of both
is now matter of history. {5}

Many skilful inventors have from time to time added new power to
the steam-engine; and, by numerous modifications, rendered it
capable of being applied to nearly all the purposes of manufacture-