By the middle of March he had sufficiently matured his ideas of a reciprocating expansive engine to enable him to take out letters patent, and the invention was enrolled on the 4th of July in the same year. It included the double engine and double-acting engine (steam pressing the piston upwards as well as downwards), the employment of steam on the expansive principle, various methods of equalising the power of the engine, the toothed rack and sector for guiding the piston-rod, and a rotative engine or steam-wheel. While perfecting these beautiful adaptations, Watt was often plunged in the depths of distress through many causes,--by sickness, headaches, and low spirits; by the pecuniary difficulties of the firm; by the repeated attempts of the Cornish miners to lower their dues; and by threatened invasions of his patent from all quarters. Another of his worries was the unsteadiness of his workmen. His letters to Boulton were full of complaints on this score. Excepting Wm. Murdock, who was in constant demand, there was scarcely one of them on whom he could place reliance. “We have very little credit, indeed,” said he, “in our Soho workmen. James Taylor has taken to dram-drinking at a most violent rate,--is obstinate, self-willed, and dissatisfied.” And again, “Cartwright’s engine has been a continued scene of botching and blunders. J. Smith and the rest are ignorant, and all of them must be looked at daily, or worse follows. Had I had any one man of common prudence and experience, who would have attended from morning till night, these things might have been avoided, and my life would have been more comfortable. As things are, it is much otherwise.”[234] Three months later, matters had not mended. J. Smith is pronounced “a very slow hand,” and “J. Taylor is sometimes three days together at the alehouse, except when he judged I should be going my rounds.... Dick Cartwright also continues too much devoted to beer.... I have read all our men lectures upon industry and good hours, though I fear it will not be to much purpose; idleness is ingrained in their constitution.”[235] Boulton wrote to him to “send home the most rascally of the Sohoites;” but this was impracticable, as better men to replace them were not at that time to be had. Things were quite as bad at Soho itself; for early in 1782 we find Boulton writing thus: “The forging-shop wants a total reformation; Peploe and others constantly drunk; spoke mildly to them at first, then threatened, and am now looking out for good hands, which are very scarce.”[236] [234] Watt to Boulton, 20th September, 1781. [235] Watt to Boulton, 20th December, 1781.