attainments, and is still known as having been the author of a translation of Macquer's' Chemistry,' and of an interesting paper on the crystallisation of glass; of another paper in the 'Philosophical Transactions' on the congelation of the vitriolic acid; of a treatise on the different kinds of permanently elastic fluids or gases, in 1777 and 1779; of a fragment of a Dictionary of Chemistry in 1789-90; as well as of an Account of the Life and Writings of the eccentric Philanthropist, Thomas Day, in 1791.

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On fully conversing with his guest as to the nature, position, and prospects of his invention, Mr. Boulton expressed a desire to be "concerned in the fire-engine;" but Mr. Watt, with that regard which throughout life he invariably showed not only to the rights and interests but also to the feelings of others, deferred entering into any agreement to that effect until he should first have seen Dr. Roebuck again on the subject, and obtained his full concurrence. This he did on returning to Scotland in October, and the result was thus communicated by him to Mr. Boulton, dated the 20th of that month :-"When you were so kind as to express a desire to "be concerned in my fire-engine, I was sorry I could not immediately make you an offer. The case is this:-By "several unsuccessful projects and expensive experiments I "had involved myself in a considerable debt before I had brought the theory of the fire-engine to its present state. "About three years ago, a gentleman who was concerned "with me died. As I had at that time conceived a very "clear idea of my present improvements, and had even made some trial of them, though not so satisfactory as has been "done since, Dr. Roebuck agreed to take my debts upon "him, and to lay out whatever more money was necessary "either for experiments or securing the invention; for which "cause I made over to him two-thirds of the property of the "invention. The debts and expenses are now about 12007. "I have been since that time employed in constructing "several working fire-engines on the common principles, as "well as in trying experiments to verify the theory. As the "Doctor, from his engagements at Bo'ness, and other business,

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"cannot pay much attention to the executive part of this, "the greatest part of it must devolve on me, who am, from my natural inactivity and want of health and resolution, "incapable of it. It gave me great joy when you seemed to "think so favourably of our scheme, as to wish to engage in "it; I therefore made it my business, as soon as I got home, "to wait on the Doctor and propose you as one I wished he "would make an offer to, which he agreed to with a great "deal of pleasure, and will write you in a few days, that if "agreeable you may be a third part concerned, on paying "the half of the cost and whatever you may think the risk "he has run deserves, which last he leaves to yourself. If you should not choose to engage on these terms, we will "make you an offer when the whole is more perfect, which I hope it will soon be." "If this reciprocating

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"engine should not [answer], it must be [from] some mecha"nical difficulty, which, I think, we may certainly get the "better of. If Dr. Small should choose to be concerned "with you in this, I have reason to think it would be agree"able to Dr. Roebuck, and would be highly so to me. If you should not choose to engage with this affair in its present state, or at any rate, you will let this letter remain a secret except to Dr. Small."

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It was in the meantime determined, while awaiting Mr. Boulton's reply, that the patent should be taken out, so as at all events to secure the property in the new engine to its inventor, and those who might be associated with him in its manufacture. On the 5th of January, 1769, accordingly, the memorable patent for "A NEW METHOD OF LESSENING THE 99 CONSUMPTION OF STEAM AND FUEL IN FIRE-ENGINES was obtained; and the relative specification in due course, that is, within four months afterwards, enrolled. Dr. Roebuck had agreed, in consideration of receiving an assignation of twothirds of the property of the invention, to defray the debt (of nearly 10007.) incurred by Mr. Watt in making the previous experiments, and also the expense of the patent, and of any further experiments; while Mr. Watt was "to attend and "conduct the experiments." In reality it turned out that

Mr. Watt had to meet all the expenses, with the exception of the debt of 10007., which Roebuck took, as agreed, upon himself; and although the funds thus required were not of any very large amount, they still were such as Mr. Watt might have had extreme difficulty in providing out of his small profits in the regular way of his business. We have ascertained that, at least to nearly the whole extent required for obtaining the patent, they were advanced by Dr. Black; who in this, as well as in many other ways, had both the ability and the inclination to promote the success of the labours of his young friend.

We need scarcely add that the sum thus provided was gratefully repaid, with interest, by Mr. Watt, when days of greater affluence had dawned upon him. But we feel pleasure in making known this instance, which we believe is not a solitary one, in which Dr. Black showed himself ready to aid a deserving neighbour less opulent than himself; as it has been alleged, probably not altogether without reason,—that the learned Doctor was somewhat penuriously attached to the saving of money. The considerable fortune which he bequeathed to his relations, (upwards of 20,0007.), certainly bore witness to his prudence as a financier no less than to his success as a physician; but on this subject we cannot do better than quote from one of his letters to Mr. Watt, written in the last year of his life, in which he says,-" You should study now to enjoy relaxation from business, and the amuse"ments which are the most suited to your taste; but above "all, relaxation and ease, and gentle exercise, and change of "air. You need not be anxious now about your fortune. It "is already abundant, and it will increase constantly, even "while you are sleeping. It is, however, one of the follies of "old age to be too intent on the accumulation of riches; and "I feel in myself a degree of that inclination. Those of us especially who have made a little fortune by our own industry, set a high value on riches on account of the labour " which they have cost us; and when time has put an end to

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*

* Dr. Black to Mr. Watt, Edinburgh, 1 Feb. 1799.

"other enjoyments, one of our greatest pleasures is to increase "the hoard. We do not consider that it is already sufficient "for every reasonable purpose. We have acquired a taste " and a habit which we indulge. If you can be amused with "the works of Horace, you will find in them many pleasant "allusions to this folly, and ingenious expositions of the absurdity of it." We can hardly imagine either a more pleasant allusion to the foible in question, or a more sound exposition of the absurdity of it, than those thus delivered by the amiable and philosophic Doctor; whose discourse sounds partly as a warning against the sin, and partly as a rather complacent confession of its commission.

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CHAPTER XIV.

SPECIFICATION OF THE PATENT OF 1769- INTERRUPTED NEGOTIATIONS— CONTINUED EXPERIMENTS EXPANSIVE POWER OF STEAM -SUCCESSFUL TRIAL OF ENGINE AT KINNEIL PIPE-CONDENSER · FURTHER NEGOTIATIONS WITH SOHO-CONTINGENT AGREEMENT WITH DR. ROEBUCK— POSITION AND CIRCUMSTANCES OF MR. WATT.

WATT, while continuing his experiments at Glasgow, and his preparations for further trials of the engine "in the glen "behind Kinneil," where "the burn afforded plenty of cold "water" for condensation, and there was greater "freedom "from speculation than about Bo'ness," now busied himself in making a draft of the Specification, which had to be given in and enrolled within four calendar months of the date of the Letters Patent. In the preparation of this document, which afterwards became one of great interest in the history of the steam-engine, not only from the nature of its contents, but also from the long and fiercely-contested litigation of which it was the turning-point, he received the benefit of the advice of his friends Dr. Small and Mr. Boulton; and the event showed that their enlarged views of the principles on which it ought to be framed, were sound and judicious.

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"Mr. Boulton and I," writes Dr. Small to Mr. Watt,* "have considered your paper, and think you should neither give drawings nor descriptions of any particular machinery, (if such omissions would be allowed at the office), but specify in the clearest manner you can that you have dis"covered some principles, and thought of new applications of "others, by means of both which, joined together, you intend "to construct steam-engines of much greater powers, and "applicable to a much greater number of useful purposes, "than any which hitherto have been constructed; that to

5 Feb. 1769.