JAMES WATT 259 Watt's negotiations for partnership with Boulton were long and tedious. Dr. Roebuck's creditors concurred because, curiously enough, none of them valued Waifs engine at a farthing. Watt himself now began to despair, and his health failed ; yet in 1 774, when he had removed to Birmingham, he wrote to his father : " The fire-engine I have invented is now going, and answers much better than any other that has yet been made ; and I expect that the invention will be very bene- ficial to me." A long series of experimental trials was, nevertheless, requisite before the en- gine 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 exten- sion 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 Par- liament. 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 con- tend 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 preju- dices. The result in the way of profit was not, however, satisfactory, notwith- standing 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 1 769) 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 recipro- cating 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 1 783 and earlier ones of 1 784, was to teach his steam-engine, now become nearly as docile as it was powerful, to work a tilt-hammer for forging iron and making steel. " Three hundred blows per minute a thing never done before," filled him, as his biographer says, with feelings of excusable pride. Another patent in the steam-engine series, taken out in 1 784, contained, besides other methods of converting a circular or angular motion into a perpendicular or rectilineal motion, the well-known and much-ad- mired parallel motion, and the application of the steam-engine to give motion to
