Watt, with his usual want of confidence in himself in business affairs, was anxious that Boulton should come to him at Glasgow and arrange all pecuniary matters connected with the marriage. Watt had faced the daughter and conquered, but trembled at the thought of facing the father-in-law. He appeals to his partner as follows:
I am afraid that I shall otherwise make a very bad bargain in money matters, which wise men like you esteem the most essential part, and I myself, although I be an enamoured swain, do not altogether despise. You may perhaps think it odd that in the midst of my friends here I should call for your help; but the fact is that from several reasons I do not choose to place that confidence in any of my friends here that would be necessary in such a case, and I do not know any of them that have more to say with the gentleman in question than I have myself. Besides, you are the only person who can give him satisfactory information concerning my situation.
This being impracticable, as explained by Boulton, who thoroughly approved of the union, the partnership and Boulton's letter were accepted by the judicious father-in-law as satisfactory evidence that his daughter's future was secure. Boulton states in his letter, July, 1776:
It may be difficult to say what is the value of your property in partnership with me. However, I will give it a name, and I do say that I would willingly give you two, or perhaps three thousand pounds for your assignment of your third part of the Act of Parliament. But I should be sorry to make you so bad a bargain, or to make any bargain at all that tended to deprive me of your friendship, acquaintance, and assistance, hoping that we shall harmoniously live to wear out the twenty-five years, which I had rather do than gain a Nabob's fortune by being the sole proprietor.
This is the kind of expression from the heart to make a partner happy and resolve to do his utmost for one who in the recipient's heart had transposed positions, and is now friend first, and partner afterward.
The marriage took place in July, 1776. Two children were born, both of whom died in youth. Mrs. Watt lived until a ripe old age and enjoyed the fruits of her husband's success and fame. She died in 1832. Arago praises her, and says "Various talents, sound judgment, and strength of mind rendered her a worthy companion."
It is difficult to realise that many yet with us were contemporaries of Mrs. Watt, and not a few yet living were contemporaries of Watt himself, for he did not pass away until 1819, eighty-six years ago, so much a thing of yesterday is the material development and progress of the world, which had its basis, start and accomplishment in the steam engine.
The reasons given by Boulton for being unable to proceed to the side of his friend and partner in Glasgow, shed clear light upon the condition of affairs at Soho. Their London agent, like Watt, was also to be married and would be absent. Fothergill had to proceed to London. Scale, one of the managers, was absent. Important visitors were constantly arriving. Said Boulton:
Our copper bottom hath plagued us very much by steam leaks, and therefore I have had one cast (with its conducting pipe) all in one piece; since which the engine doth not take more than 10 feet of steam, and I hope to reduce that quantity, as we have just received the new piston, which shall be put in and at work tomorrow. Our Soho engine never was in such good order as at present. Bloomfield and Willey (engines) are both well, and I doubt not but Bow engine will be better than any of 'em.
He concludes, "I did not sleep last night, my mind being absorbed by steam." Means for increasing the heating surface swept through his mind, by applying "in copper spheres within the water," the present flue system, also for working steam expansively, "being clear the principle is sound."