tin-plate, the ends of the brass cylinder, a, of a syringe one and three-quarters inch in diameter, and ten inches long. A valve was fixed at the lower orifice of a longitudinal perforation made through the axis of the piston-stem, b, which was placed to move downwards. Two tin-plate pipes, c, d, about one-sixth of an inch in diameter and ten inches long, placed perpendicularly, communicated at top with a short horizontal pipe, e, of large diameter, shut at its upper end, having a valve, i, opening upwards; these pipes were connected at bottom with another perpendicular pipe,

Mr. More, on this occasion, was asked, whether he had read the specification of Mr. Watt's invention, and whether, in his opinion, it contained a disclosure of the principles of the steam-engine? To this question he answered, I am fully of opinion that it contains the principles entirely, clearly, and demonstratively.' He was then asked, Did you ever meet with the application of these principles before you knew of Mr. Watt's engine?' his answer was, 'I do declare I never saw the principles laid down in Mr. Watt's specification, either applied to the steam-engine previous to his taking it It is not up, or ever read of any such thing whatever.' easy to reconcile these two answers given by that gentleman on his oath, with the words that Mr. Hornblower has put into his mouth. Mr. Gainsborough's idea, whatever it was, was posterior by more than twenty years." (?) p. 328, vol. xiii. We know not if the claim which is put forth in the above extract, is the same as that alluded to by the late venerable Professor Jardine. "I happened," says he, "to be tutor to Dr. Roebuck's sons at that time (when Watt was at Kinneil); I had then the pleasure of seeing the experiments on a great scale, which were carrying on. This accidental circumstance, and this opportunity, connected me so much with what was going on, that when they were completed, I was asked by Mr. Watt to go with him to Berwick, when he went to give in a specification of his invention before a Master in Chancery, previous to the obtaining of a patent. And many years afterwards, when a groundless and frivolous charge was brought against Mr. Watt, by a person who claimed a share in the invention, I was called to give evidence of what I knew of this in Chancery. It is needless to add, Mr. Watt was triumphantly victorious."

o, about an inch in diameter, and ten inches long; this was furnished with a piston, a, and served for a pump; a pipe, s, conveyed steam from a boiler to the top and bottom of the cylinder.—(Engraving marked WATT L., fig. 2.)

Having placed the pistons at the bottoms of their respective vessels, he admitted the steam from the boiler to flow into the cylinder until it escaped through the perforation in the stem, and through the valve into the condenser. When he thought all the air was expelled from these vessels, he shut the steam-cock, and drew up the piston in the small pump; the steam rushed into them was condensed, and a vacuum being thus produced above the piston, and its under side being open to the boiler, the piston in the cylinder rose and lifted a weight of eighteen pounds which was hung to the lower end of its rod. He again shut the exhaustion-cock, and admitted steam, and the operation was repeated; and thus a hot cylinder and a perfect vacuum, which all previous engineers had wished for, sought for, but abandoned as hopeless, were produced by means almost rivalling those of nature herself, in their simplicity.

So favourable a result, with such an imperfect apparatus, gave him confidence to attempt a second experiment. He knew the varying and often most contradictory results from an engine on the scale of a model, and one of dimensions adapted to practice; and although in his experiments the smallness of his cylinders gave a great advantage to those of large proportions, yet other parts of his mechanism might be differently effected. A large model, however, required a large room, and his usual place of business offered no convenience of constructing a machine of any

238

SECOND MODEL.

magnitude, and yet conceal its parts, and preserve the secret of its principle.

He had assisted one of his friends in establishing a small pottery at a short distance from the town, and held a share in its property. He appropriated one of the rooms of this "Delft Work" to his purpose, and, assisted by his ingenious apprentice, John Gardiner, he began the construction of his second model on a scale of some magnitude. The cylinder had a diameter of nine inches, and was enclosed by a casing of wood, and its piston-rod was attached to a balanced lever. An accident terminated his operations with this engine; the beam broke, and neither his leisure nor his means enabling him to repair the damage, the model was thrown aside, and his project was suspended. He states, however, in his narrative, that the saving of steam, and the increase of power which it indicated, satisfied his expectations.

His practice as a land-surveyor, to which he was devoting himself, introduced him to employment as an engineer. He made various surveys for lines of canal, and he was intrusted with the superintendence of a short one, which was formed between the Monkland collieries and Glasgow. But whether it was from a wish not to interfere with those arrangements to which he had pledged his time, or the fear of the opposition which he might encounter, or a diffidence in the project, or himself, that for three or four years prevented a disclosure of his discovery, even to his friends, is not known; but he seems to have felt that a fair trial could only be given to his invention by the erection of an engine on a large scale, and, above all other mechanisms, the steam-engine, in its simplest form, was one of the most costly; and who, in this community, could he hope to induce to hazard

some thousands of pounds on the chance of a mere experiment, with a machine then little used, and less understood in his neighbourhood? for, it should not be forgotten, that the system of commercial adventure was very different then from what it is now. Pedlars who at this time were gathered to their fathers, slept in dignity, with "merchant" inscribed on their tomb stones, and their higgling spirit was inherited by their children. Some small fortunes had been made in the foreign trade, few had been risked in any; and a solitary instance was all that could be held up as a stimulus to excite the hope of a fortune being realized by a manufacturing speculation.