cannot suppose that less than twelve engines will be wanted in two or three years, but after that very few more, as these will be sufficient to get ore enough; though you cannot reckon the average profits to us at above 200_l._ per engine.” When Boulton and Watt first started the manufacture of steam-engines, they were mainly concerned to get orders, and were not very particular as to the terms on which they were obtained. But when the orders increased, and the merits of the invention gradually became recognised, they found it necessary to require preliminary agreements to be entered into as to the terms on which the patent was to be used. It occurred to them, that as one of its principal merits consisted in the saving of fuel, it would be a fair arrangement to take one-third of the value of such saving by way of royalty, leaving the owners of the engines to take the benefit of the remaining two-thirds. Nothing could be fairer than the spirit of this arrangement, which, it will be seen, was of even more advantage to the owners of the engines than to the patentees themselves. The first Cornish engines were, however, erected without any condition as to terms; and it was only after they had proved their power by “forking” the water, and sending the miners twenty fathoms deeper into the ground, that the question of terms was raised. Watt proposed that agreements should be entered into on the basis above indicated. But the Cornish men did not see the use of agreements. They had paid for the engines, which were theirs, and Boulton and Watt could not take them away. Here was the beginning of a long series of altercations, which ended only with the patent right itself. The miners could not do without the engine. It was admitted to be of immense value to them, rendering many of their mines workable that would otherwise have been valueless. But why should they have to pay for the use of such an invention? This was what they never could clearly understand. To prevent misunderstandings in future, Watt wrote to Boulton, recommending that no further orders for engines should be taken unless the terms for using them were definitely settled beforehand. “You must excuse me,” he added, “when I tell you that, for my part, I will not put pen to paper [_i. e._ make the requisite drawings] on a new subject until that is done. Until an engine is ordered, our power is greater than that of the Lord Chancellor; as I believe even he cannot compel us to make it unless we choose. Let our terms be moderate, and, if possible, consolidated into money _à priori_, and it is certain we shall get _some_ money, enough to keep us out of jail, in continual apprehension of which I live at present.”[168]