In the mean time, the works at Soho continued to be fully employed in the manufacture of pumping-engines. But as the county of Cornwall was becoming well supplied,--no fewer than twenty-one having now been erected there, only one of the old Newcomen construction continuing in work,--it was probable that before long the demand from that quarter must slacken, if not come to an end. There were, however, other uses to which the pumping-engine might be applied; and one of the most promising was the drainage of the Fen lands. Some adventurers at Soham, near Cambridge, having made inquiries on the subject, Watt wrote to his partner, “I look upon these Fens as the only trump card we have left in our hand.”[256] The adventurers proposed that Boulton and Watt should take an interest in their scheme by subscribing part of the necessary capital. But Watt decidedly objected to this, as he did not wish to repeat his Cornish difficulties in the Fens. He was willing to supply engines on reasonable terms, but as for shares he would have none of them. The conclusion he eventually arrived at with respect to his proposed customers was this,--“Consider Fen men as Cornish men, only more cunning.” In the midst of his great labours, Boulton was reminded that he was human. He had for years been working at too high pressure, and the tear and wear began to tell upon his health. Watt expostulated with him, telling him that he was trying to do half-a-dozen men’s work; but in vain. He was committed to so many important enterprises--he had so much at stake--the liabilities he had to meet from day to day were so heavy--that he was in a measure forced to be active. To his friend Matthews he lamented that he was under the necessity of “slaving from morning till night, working fourteen hours a day, in the drudgery of a Birmingham manufacturer and hardware merchant.” But this could not last, and before long he was threatened with a break-down. His friends Drs. Withering and Darwin urged him at once to “knock off” and take a long holiday--to leave Soho and its business, its correspondence, and its visitors, and get as far away from it as possible. [256] 4th December, 1782.