When steam was produced, it was admitted into the cylinder and soon issued through the perforation of the rod, and at the valve of the condenser: when it was judged that the air was expelled, the steam cock was shut, and the air pump piston rod was drawn up, which, leaving the small pipes of the condenser in a state of vacuum, the steam entered them and was condensed. The piston of the cylinder immediately rose and lifted a weight of about 18 lbs. which was hung to the lower end of the piston rod. The exhaustion rod was shut, the steam was readmitted into the cylinder, and the operation repeated. The quantity of steam consumed and the weights it could raise were observed, and, excepting the non-application of the steam case and external covering, the invention was complete in so far as regarded the saving of steam and fuel.

“My whole thoughts are bent on this machine. I can think of nothing else,” he said. He made another and more satisfactory engine in a larger apartment within an old pottery, near his house in the lane. He was greatly hindered by the want of skilled workmen. He could not get his cylinder and other parts of the machine properly made. He also lacked the capital to make it known and protect it. Most fortunately there was in the neighbourhood Dr. Roebuck, the founder of the Carron Iron Works, a gentleman of extensive knowledge in all the branches of civil engineering. He was also well accustomed to great enterprises, not scared by difficulties, or sparing in expense. In 1767, when Watt had become considerably involved by the expenses in perfecting his engine, Roebuck assumed his liabilities, to the amount of £1,000, and agreed to provide capital for the prosecution of experiments, and to introduce the invention. In return, Watt agreed to assign to Roebuck two-thirds of his patent, which was granted in 1769.

In accordance with this arrangement, Watt proceeded in that year to take out his patent, and to erect his first engine which came to be named “Beelzebub” — because of the mystery by which it was surrounded, and the power it was expected to display in the world. It was erected in an outhouse (in order to avoid prying eyes) behind the Kinneil mansion near Borrowstonness, which was then the residence of Dr. Roebuck. The cylinder, 18 inches diameter and five feet stroke, was cast at Carron; the most of the other materials were brought from Mr. Watt’s works at Glasgow. It was slow and trying work. He had to complain of the “villainous bad work.” The truth is, the men were not up to it, and whenever he was away, things went wrong. At