Much, however, remained to be done before either Watt or Boulton could reap any benefit from the invention. Six years out of the fourteen for which the patent was originally taken had already expired; and all that had been accomplished was the erection of this experimental engine at Soho. What further period might elapse before capitalists could be brought to recognise the practical uses of the invention could only be guessed at; but the probability was that the patent right would expire long before such a demand for the engines arose as should remunerate Boulton and Watt for their investment of time, labour, and capital. And the patent once expired, the world at large would be free to make the engines, though Watt himself had not recovered one farthing towards repaying him for the long years of experiment, study, and ingenuity bestowed by him in bringing his invention to perfection. These considerations made Boulton hesitate before launching out the money necessary to provide the tools, machinery, and buildings, for carrying on the intended manufacture on a large scale and in the best style. When it became known that Boulton had taken an interest in a new engine for pumping water, he had many inquiries about it from the mining districts. The need of a more effective engine than any then in use was every year becoming more urgent. The powers of Newcomen’s engine had been tried to the utmost. So long as the surface-lodes were worked, its power was sufficient to clear the mines of water; but as they were carried deeper, it was found totally inadequate for the work, and many mines were consequently becoming gradually drowned out and abandoned. The excessive consumption of coals by the Newcomen engines was another serious objection to their use, especially in districts such as Cornwall, where coal was very dear. When Small was urging Watt to come to Birmingham and make engines, he wrote: “A friend of Boulton’s, in Cornwall, sent us word a few days ago that four or five copper-mines are just going to be abandoned because of the high price of coals, and begs us to apply to them instantly. The York Buildings Company delay rebuilding their engine, with great inconvenience to themselves, waiting for yours. Yesterday application was made to me by a Mining Company in Derbyshire to know when you are to be in England about the engines, because they must quit their mine if you cannot relieve them.” The necessity for an improved pumping power had set many inventors to work besides Watt, and some of the less scrupulous of them were already trying to adopt his principle in such a way as to evade his patent. Moore, the London linendraper, and Hatley, one of Watt’s Carron workmen, had brought out and were pushing engines similar to Watt’s; the latter having stolen and sold for a considerable sum working drawings of the Kinneil engine.