The engine was shortly after finished, mounted in a strong oak frame, and taken to Dalswinton. It was then placed on the deck of Mr. Miller’s double pleasure-boat, twenty-four feet long and seven broad, which had been prepared for its reception.
MR. MILLER’S EXPERIMENTAL STEAMBOAT.
The engine was placed on one side of the boat, the boiler on the other side to balance it, and the paddle-wheels in the middle; the rotary motion being obtained from the engine by chains, ratchet-wheels, and catches. The first experiment was tried on the 14th of October, 1788, and proved successful, the engine being propelled at the rate of five miles an hour.[371] Among the persons present on the occasion, besides Miller, Symington, and Taylor, were Alexander Nasmyth, the landscape painter, and Robert Burns, the poet, then a tenant of Mr. Miller on the neighbouring farm of Ellisland. After a few further experiments the engine was taken out of the boat and carried into Mr. Miller’s house, where it remained for many years, and was eventually deposited in the Museum of Patents at Kensington, where it is now to be seen.
The experiments made with this first steamboat were so satisfactory that Mr. Miller resolved to try one upon a larger scale. By this time Messrs. Allen and Stewart, of Leith, had built for him another double vessel, ninety feet in length; and he wrote to Symington, requesting his estimate of the cost of fitting it with a suitable steam-engine. Symington’s reply was to the effect that a proper-sized engine for such a vessel would, in his opinion, be about 250l., including the float-wheels. The necessary order was given, and Symington proceeded to the Carron Ironworks for the purpose of constructing it. The vessel arrived at Carron on the 24th June, and by the month of November following the engine was finished and put on board ready for trial.[372] The result was not so satisfactory as in the case of the experiment on Dalswinton Loch. The paddle-wheels were too weak; first one float and then another broke off; and the trial had to be suspended until the defects were remedied. The next trial was, however, more satisfactory. The vessel reached a speed of seven miles an hour; and this was repeated with the same result. There must, however, have been some defect in the engine performances; for, in a letter written by Miller to Taylor, who was present throughout, he expressed the opinion that Symington’s engine was altogether unsuitable for giving motion to a vessel.[373] He accordingly ordered the engine to be taken out and placed in the Carron Works, and the vessel itself to be laid up at Bruce Haven.
Thus matters remained until the spring of the following year, when Mr. Miller decided on applying to Boulton and Watt for an engine of a proper construction, offering at the same time to associate them with him in his enterprise. The negotiation was opened by Robert, afterwards Lord Cullen, who addressed Watt on the subject; but his reply was not encouraging. Like his partner, Watt was averse to new speculations; and he had had too much anxiety and worry in connexion with his original enterprise to enter upon any new one. It will also be observed that he entertained doubts as to the eventual success of ocean navigation by steam. The following was his reply:—
“Dear Sir,—We have heard of Mr. Miller’s ingenious experiments on double ships from Sir John Dalrymple, and also some vague accounts of the experiments with the steam-engine, from which we could gather nothing conclusive, except that the vessel did move with a considerable velocity.
“From what we heard of Mr. Symington’s engines, we were disposed to consider them as attempts to evade our exclusive privilege; but as we thought them so defective in mechanical contrivance as not to be likely to do us immediate hurt, we thought it best to leave them to be judged by Dame Nature first before we brought them to any earthly court.
“We are much obliged to Mr. Miller for his favourable opinion of us and of our engines, which we hope experience would more and more justify. We are also fully sensible of his kind intentions in offering to associate us with him in his scheme; but the time of life we have both arrived at, and the multiplicity of business we are at present engaged in, must plead our excuse for entering into any new concern whatever as partners; but as engineers and engine-makers we are ready to serve him to the best of our abilities, at our customary prices, for rotative engines, and to assist in anything we can do to bring the scheme to perfection.
“We conceive that there may be considerable difficulty in making a steam-engine to work regularly in the open sea, on account of the undulating motion of the vessel affecting the vis inertiæ of the matter; however, this we should endeavour to obviate as far as we could.