g, and answers much better
than any other that has yet been made; and I expect that the
invention will be very beneficial to me."

A long series of experimental trials was, nevertheless, requisite
before the engine could be brought to such perfection as to render
it generally available to the public, and therefore profitable to
its manufacturers. In January, 1775, six years of the patent had
elapsed, and there seemed some probability of the remaining eight
running out as fruitlessly. An application which was made for the
extension of its term was unexpectedly opposed by the eloquence of
Burke; but the orator and his associates failed, and the extension
was accorded by Act of Parliament.

The first practical employment of Watt's engines to any considerable
extent was in the mining districts of Cornwall, where he himself
was, in consequence, compelled to spend much of his time subsequent
to 1775. Here he had to contend not only with natural obstacles in
the dark abysses of deeply flooded mines, but with a rude and
obstinate class of men as deeply flooded by inveterate prejudices.
The result in the way of profit was not, however, satisfactory,
notwithstanding the service to the mining interest was enormous. "It
appears," says Watt, in 1780, "by our books, that Cornwall has
hitherto eat up all the profits we have drawn from it, and all we
have got by other places, and a good sum of our own money to the
bargain."

At this stage Watt himself was more fertile in mechanical inventions
than in any other portion of his busy life. Taking his patents in
their chronological order, the first (subsequent to that of 1769)
was "For a new method of copying letters and other writings
expeditiously," by means of copying _presses_. Of the same date was
his invention of a machine "for drying linen and muslin by steam."
On October 25, 1781, he took out his third patent (the second of the
steam-engine series), "for certain new methods of applying the
vibrating or reciprocating motion of steam or fire engines, to
produce a continued rotative motion round an axis or centre, and
thereby to give motion to the wheels of mills or other machines."
One of these methods was that commonly known as the _sun-and-planet
wheels_; they were five in all. A favorite employment of his in the
workshops at Soho, in the later months of 1783 and earlier ones of
1784, was to teach his steam-engine, now become nearly as docile as
it was powerful, to work a tilt-