This engine had a steam-cylinder, Watt tells us, of “five or six” inches diameter, and of two feet stroke. It was of copper, smooth-hammered, but not bored out, and “not very true.” This was encased in another cylinder of wood. In August, 1765, he tried the small engine, and wrote Dr. Roebuck that he had had “good success,” although the machine was very imperfect. “On turning the exhausting-cock, the piston, when not loaded, ascended as quick as the blow of a hammer, and as quick when loaded with 18 pounds (being 7 pounds on the inch) as it would have done if it had had an injection as usual.” He then tells his correspondent that he was about to make the larger model. In October, 1765, he finished the latter. The engine, when ready for trial, was still very imperfect. It nevertheless did good work for so rude a machine.
Watt was now reduced to poverty, and, after borrowing considerable sums from friends, he was finally compelled to give up his scheme for the time, and to seek employment in order to provide for his family. During an interval of about two years he supported himself by surveying, and by the work of exploring coal-fields in the neighborhood of Glasgow for the magistrates of the city. He did not, however, entirely give up his invention.
In 1767, Dr. Roebuck assumed Watt’s liabilities to the amount of £1,000, and agreed to provide capital for the prosecution of his experiments and to introduce his invention; and, on the other hand, Watt agreed to surrender to Dr. Roebuck two-thirds of the patent. Another engine was next built, having a steam-cylinder seven or eight inches in diameter, which was finished in 1768. This worked sufficiently well to induce the partners to ask for a patent, and the specifications and drawings were completed and presented in 1769.
Watt also built and set up several Newcomen engines, partly, perhaps, to make himself thus thoroughly familiar with the practical details of engine-building. Meantime, also, he prepared the plans for, and finally had built, a moderately large engine of his own new type. Its steam-cylinder was 18 inches in diameter, and the stroke of piston was 5 feet. This engine was built at Kinneil, and was finished in September, 1769. It was not all satisfactory in either its construction or its operation. The condenser was a surface-condenser composed of pipes somewhat like that used in his first little model, and did not prove to be satisfactorily tight. The steam-piston leaked seriously, and repeated trials only served to make more evident its imperfections. He was assisted in this time of need by both Dr. Black and Dr. Roebuck; but he felt strongly the risks which he ran of involving his friends in serious losses, and became very despondent. Writing to Dr. Black, he says: “Of all things in life, there is nothing more foolish than inventing;” and probably the majority of inventors have been led to the same opinion by their own experiences.
“Misfortunes never come singly;” and Watt was borne down by the greatest of all misfortunes—the loss of a faithful and affectionate wife—while still unable to see a successful issue of his schemes. Only less disheartening than this was the loss of fortune of his steadfast friend, Dr. Roebuck, and the consequent loss of his aid. It was at about this time, in the year 1769, that negotiations were commenced which resulted in the transfer of the capitalized interest in Watt’s engine to the wealthy manufacturer whose name, coupled with that of Watt, afterward became known throughout the civilized world, as the steam-engine in its new form was pushed into use by his energy and business tact.
Watt met Mr. Boulton, who next became his partner, in 1768, on his journey to London to procure his patent, and the latter had then examined Watt’s designs, and, at once perceiving their value, proposed to purchase an interest. Watt was then unable to reply definitely to Boulton’s proposition, pending his business arrangements with Dr. Roebuck; but, with Roebuck’s consent, afterwards proposed that Boulton should take a one-third interest with himself and partner, paying Roebuck therefor one-half of all expenses previously incurred, and whatever he should choose to add to compensate “for the risk he had run.” Subsequently, Dr. Roebuck proposed to transfer to Boulton and to Dr. Small, who was desirous of taking interest with Boulton, one-half of his proprietorship in Watt’s inventions, on receiving “a sum not less than one thousand pounds,” which should, after the experiments on the engine were completed, be deemed “just and reasonable.” Twelve months were allowed for the adjustment of the account. This proposal was accepted in November, 1769.
Matthew Boulton.
[Matthew Boulton], who now became a partner with James Watt, was the son of a Birmingham silver stamper and piecer, and succeeded to his father’s business, building up a great establishment, which, as well as its proprietor, was well known in Watt’s time. Watt, writing to Dr. Roebuck before the final arrangement had been made, urged him to close with Boulton for “the following considerations: