"factory, and himself writing volumes of other letters on

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business, which alone would have furnished full employ"ment even to an industrious intellect." His mind also," continues the same excellent authority, "had been greatly "affected by his unavoidable absence from the death-bed "of his aged father; and during the greater part of the "time, I well remember seeing him suffer under most acute "sick headaches, sitting by the fireside for hours together, "with his head leaning on his elbow, and scarcely able to "give utterance to his thoughts. It was unquestionably the "busiest as well as the most anxious period of his life, and fraught with the most important results."

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Often, in the course of the period of which we have been speaking, especially towards its close, we find him uttering complaints of his bad health, of what he calls his own stupidity," and "want of the inventive faculty;" complaints which, had they issued from less sincere lips, might have been almost deemed ironical, but were with him, like everything else that he uttered, the honest expression of the true feelings of his mind. Towards the close of 1785, he says, "my own health is so bad that I do not think I can hold out "much longer, at least as a man of business." "I cannot help being dispirited, because I find my head fail me much; "business an excessive burden to me, and little prospect of any speedy release from it. Were we both young and "healthy, I see no reason to despair, but very much the con

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trary; however, we must do the best we can, and hope for quiet in Heaven, when our weary bones are laid to rest :”"on the whole, I find it now full time to cease attempting to "invent new things, or to attempt anything which is attended "with any risk of not succeeding, or of creating trouble "in the execution. Let us go on executing the things "we understand, and leave the rest to younger men, who "have neither money nor character to lose." Early in 1786, also, he writes:-" in the anguish of my mind amid the vex"ations occasioned by new and unsuccessful schemes, like Lovelace, I curse my inventions,' and almost wish, if we "could gather our money together, that somebody else should "succeed in getting our trade from us." And, in June of the same year, "I should have written to you long ago, but have really been in a worse situation in some respects this spring "than I have ever been in my life. The illness I was "seized with in London in the spring greatly weakened me "both in body and mind; and, I believe, was brought on by "over-exertions, endeavouring to get home as soon as pos"sible. The bodily disease has in great measure subsided; "but an unusual quantity of business, which by Mr. Boulton's frequent and long absences has fallen wholly on me, and "several vexations, with the consequent anxious thoughts, "have hitherto prevented my mind from recovering its energy. I have been quite effete and listless, neither daring to face business, nor capable of it; my head and "memory failing me much; my stable of hobby-horses pulled down, and the horses given to the dogs for carrion. "In such a situation it requires something very pressing, or very animating, to make one put pen to paper. I have "had serious thoughts of throwing down the burthen I find myself unable to carry, and perhaps, if other sentiments "had not been stronger, should have thought of throwing off "the mortal coil; but, if matters do not grow worse, I may perhaps stagger on. Solomon said that in the increase of knowledge there is increase of sorrow: if he had substituted "business for knowledge, it would have been perfectly true."

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The history of one other patent will exhaust the series of

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those taken out by Mr. Watt. On the 25th of March, 1785, he wrote to Mr. Boulton, "I think we are in the way of getting quit of smoke in the engines;" and on the 10th of September in the same year, to Mr. De Luc, "I have some hopes of being able to get quit of the abominable smoke "which attends fire-engines. Some experiments which I It is not on Mr. Argand's

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"have made promise success.

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principle, but on an old one of my own, which is exceedingly different." On the 9th of October, "We had a first "trial yesterday of a large furnace to burn without smoke "under the big boiler, at Soho, that used to poison Mr. B.'s garden so much, and it answered very well, as far as we "could judge from a wet furnace, and without the engines being at work."

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Of the date of this invention being devised or completed by Mr. Watt, we have no more exact information; but in September of the same year in which he obtained his patent for it, he mentioned that the principle on which it proceeded was an old one of his own." Until that time, he does not appear ever to have tried it on a large scale; but, both then and since, it has, we believe, been always found to answer well in practice. "It is astonishing," writes his son Mr. James Watt to him from Manchester in 1790, "what an

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impression the smoke-consuming power of the engine has “made upon the minds of everybody hereabouts; nobody "would believe it until the engine was set a-going, and even "then they scarcely trusted to the evidence of their senses. "You would be diverted to hear the strange hypotheses "which have been started to account for it. However, it has "answered one extremely good end, it has made your engines general topics of conversation, and consequently universally known; which they were by no means before in "this country." And on the 14th of June, 1785, he took out a patent" for certain newly improved methods of constructing furnaces or fire-places for heating, boiling, or evaporating of water and other liquids which are applicable to "steam-engines and other purposes, and also for heating, melting, and smelting of metals and their ores, whereby

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greater effects are produced from the fuel, and the smoke is "in a great measure prevented or consumed," which newly improved methods he describes to consist "in causing the smoke or flame of the fresh fuel, in its way to the flues or chimney, "to pass together with a current of fresh air through, over, "or among fuel which has already ceased to smoke, or which "is converted into coke, charcoal, or cinders, and which is intensely hot, by which means the smoke and grosser parts "of the flame, by coming into close contact with, or by "being brought near unto the said intensely hot fuel, and by being mixed with the current of fresh or unburnt air, "are consumed or converted into heat, or into pure flame "free from smoke."

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"I put this in practice," he continues,-" First, by stopping up every avenue or passage to the chimney or flues, "except such as are left in the interstices of the fuel, by

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placing the fresh fuel above, or nearer to the external air, “than that which is already converted into coke or charcoal; "and by constructing the fire-places in such manner that the "flame, and the air which animates the fire, must pass down“wards, or laterally or horizontally, through the burning "fuel, and pass from the lower part, or internal end or side "of the fire-place, to the flues or chimney. In some cases, "after the flame has passed through the burning fuel, I "cause it to pass through a very hot tunnel, flue, or oven, "before it comes to the bottom of the boiler, or to the "part of the furnace where it is proposed to melt metal, or perform other office, by which means the smoke is still more effectually consumed. In other cases I cause the " flame to pass immediately from the fire-place into the space "under a boiler, or into the bed of a melting or other "furnace." He varied the figure or form and proportions of the fire-places, &c., but in all cases the principle was the same; the fresh or raw fuel being placed next to the external air, and so that the smoke or flame passed over or through the coked or charred part of the fuel.

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"Secondly," he goes on, "in some cases I place the fresh “fuel on a grate as usual, and beyond that grate, at or near

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"the place where the flame passes into the flues or chimneys, "I place another small grate, on which I maintain a fire of "charcoal, coke, or coals which have been previously burnt "until they have ceased to smoke; which, by giving intense “heat and admitting some fresh air, consumes the smoke of "the first fire.

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Lastly, be it remembered," he concludes, " that my said "new invention consists only in the method of consuming the "smoke and increasing the heat, by causing the smoke and "flame of the fresh fuel to pass through very hot tunnels or

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pipes, or among, through, or near fuel which is intensely "hot, and which has ceased to smoke, and by mixing it with "fresh air when in these circumstances; and in the form and "nature of the fire-places herein mentioned, described, and "delineated: the boilers and other parts of the furnaces "being such as are in common use. And be it also remem"bered, that these new invented fire-places are applicable to furnaces for almost every use or purpose."

The Specification, which was enrolled on the 9th of July, 1785, is printed in the Mechanical Inven

tions of James Watt,' 1854, vol. iii.

pp. 115 to 121; and the relative drawings are engraved on Plates XXX., XXXI., XXXII., and XXXIII. of the same work.