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TRANSACTIONS

OF THE

GLASGOW ARCHEOLOGICAL SOCIETY.

NO. I.

REMINISCENCES OF JAMES WATT:

BY

ROBERT HART, Esq.

[Read at a Meeting of the Society held at Glasgow, on 2nd November, 1857.]

As some of the members of the Society expressed a desire at our last meeting, that I would give some recollections of the interviews that my late brother (Mr. John Hart) and myself had with the celebrated Dr. James Watt, the inventor of our improved steam-engine, I have accordingly thrown together the following brief narrative:As these meetings took place forty-three years since, many observations that were made at the time may have escaped me at present; yet, when the same subjects are touched on, I have as distinct recollection of his treatment of them as if it were of yesterday. My brother and I had heard and read much of the inventions of Mr. Watt. They were so numerous, so various, and of so valuable a character, and were so likely to change for the better the character of the mechanical and mercantile world, we had formed a very high opinion of Mr. Watt, and looked upon him as the greatest and most useful man that ever lived. To have the pleasure of conversing with him was a thing we had little hope of. However, one forenoon while we were at work, one of our employers, a Miss M'Gregor, and a tall elderly gentleman came into the shop. She, without saying who he was, asked if we would show this gentleman our small engine.

It was not going at the time, and was covered up; my brother uncovered it. The gentleman examined it very minutely, and put a few pointed questions about her (the engine), and asked our reason for making it in that form? My brother, seeing he understood the subject, said that we made her to try what we thought was an improvement, and for this experiment we required another cistern and air-pump; and he was beginning to show what was properly Mr. Watt's engine, and what was not, when, at this observation, Miss. M'Gregor stopped him by saying, "Oh, he understands it; this is Mr. Watt." I never at any time saw my brother so much excited as he was at that moment. He called on me to join them, saying that "this was Mr. Watt." Up till this time I had continued to work at what I was doing when they came, and although I heard all that was said I had not joined the party till I learned who he was. Our supposed improvement was to save condensing water, and was on the principle introduced by Sir John Leslie, to produce cold by evaporation in a vacuum. Mr. Watt took much interest in this experiment, and said he had tried the same thing on a large scale, but without the vacuum, as that invention of Professor Leslie's was not known at that time; he tried it exposed to the air, and also kept wet; and at one of the large porter breweries in London he had fitted up an apparatus of the same nature. The pipes forming his condenser were laid in the water of the river Thames, but he could not keep them tight, from the expansion and contraction of the metal, as these were exposed to various temperatures. In speaking of his early experiments with Newcomon's engine, he said he tried canes for steam pipes, but found they would not do a second time, as they were always split; this he found was caused by the absorption of water by the soft woody part inside, which expanded it and split the outside shell. He asked if ever we had tried any experiments with a Newcomon's? We informed him that we had, and also on Savery'swe having made one of each, and these we had given to the Andersonian University. This turned the conversation on these first experiments in the small way, and he entered into all the details, of making joints, &c. He was much pleased with the simple way in which we made our temporary steam joints, which was to mix a little flour and water, dip a rag into it, and apply two or three turns round the joint; as soon as it got the steam it became quite tight. He said this conversation put him in mind of his younger days.

We waited upon him that night in Miss M'Gregor's, by invitation,

and found him alone with the ladies. In the course of conversation, which embraced all that was new at the time, the expansion and the slow contraction of metals were touched on. This led to a discussion on iron in engine-making. On that, he said—" We keep the various qualities of iron for the parts they are best fitted for." As an instance, he said "We take the iron nearest to the quality of steel for our cylinders, although more difficult to bore and finish; yet, after these cylinders are used, they become smooth as a watch spring." These were his words. Then all the other parts that are to be fixed on this cylinder were made of iron of same expansibility, or as near as possible to that of the cylinder. By these means the joints never gave any trouble; but without this precaution they were often faulty, &c. I give the above to show how minutely clear he made the subject.

In speaking of the difficulties Watt and Bolton had to contend with at first, He said :-"We used to send out a cylinder of double the size wanted, and cut off the steam at half-stroke. This was a great saving of steam as long as the valves were left as first set; but when our men had left her to the charge of the person who was to keep her, he began to make improvement; often by giving more 'steam, the engine did more work while the steam lasted, but the boiler could not keep up the demand. Then complaints of want of steam came, and we had to send a man down to see what was wrong. This was so expensive, that we resolved to give up the expansion of the steam until we could get men that could work it, as a few tons of coal per year was less expensive than having the work stopped. In some of the mines a few hours stoppage was a serious matter, as it cost the proprietor £70 per hour." He also said "When Mr. Murdoch introduced the slide valve I was very much against it, as I did not think it so good as the pupet valve; but I gave in from its simplicity."

On my brother mentioning, as one of his early recollections, a shop in the High Street, opposite the College, that used to take his particular attention, from the optical and mathematical apparatus in the window, and asking him if that was his shop, he gave a smile and said-" Na, na, lad; it was not mine. I was not so rich as to have a shop of that kind."

To the question, if it was in the College that he experimented on the engine, and invented the condenser? (as we had been told it was there by persons connected with the College) he said "No, it was

not there. I believe the Faculty would very willingly connect the invention with the College, now that it had been of some use to the world."

This was followed up by my brother saying, I should like much to know where the idea first struck you, and what led you to it? He said "It was in the Green of Glasgow. I had gone to take a walk on a fine Sabbath afternoon. I had entered the Green by the gate at the foot of Charlotte Street-had passed the old washing-house. I was thinking upon the engine at the time, and had gone as far as the Herd's-house, when the idea came into my mind, that as steam was an elastic body it would rush into a vacuum, and if a communication was made between the cylinder and an exhausted vessel, it would rush into it, and might be there condensed without cooling the cylinder. I then saw that I must get quit of the condensed steam and injection water, if I used a jet as in Newcomon's engine. Two ways of doing this occurred to me. First, the water might be run off by a descending pipe, if an offlet could be got at the depth of 35 or 36 feet, and any air might be extracted by a small pump; the second was to make the pump large enough to extract both water and air." He continued, “I had not walked farther than the Golfhouse [about the site of the Humane Society-house, or a little to the N.W. of that] when the whole thing was arranged in my mind.”

In putting the invention to the trial, he said he used a small cylinder with the mouth down, and hung a weight to the piston rod, which was a tube with a valve opening outwards. This was to allow the air to be blown out, as with the sniff-pipe of Newcomon's; and hanging the mouth down was to save a beam and framework. The condenser was formed of pipes laid horizontal, and had a small air-pump at one end, all under water, that it might be kept cool, and condense the steam by external cold, as he did not use a jet. He placed a cover on the mouth of the cylinder, with a stuffing round the piston rod, as he wished to keep the air out of the cylinder, and to act on it only by steam. To effect this he connected both ends of his cylinder with the boiler by pipes, and the bottom by a pipe to the condenser; each of these pipes had a stopcock. He produced the vacuum in the condenser by working the pump by hand, having freed his cylinder of air by allowing the steam to blow through it freely, by the valve on the piston rod. He then shut off the steam from above the piston, and opened the communication with the condenser, when instantly the piston was raised by the steam under it,

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