20 
THE CORNISH PUMPING ENGINE. 
THE ERA OF WATT, 1776 TO 1800. 
29. The history of Watt’s improvements to the steam engine is so well known, 
that it is sufficient here to coniine ourselves to such facts and dates as have more 
particular reference to the introduction and use of his engine in Cornwall. 
The date of Watt’s first and principal patent was 1769, and it was prolonged by 
Act of Parliament, in 1775, for twenty-five years from that date. The first suc 
cessful engine on a large scale was made just before the passing of that Act, namely, 
about the latter end of 1774, and immediately after the commencement of Watt’s 
connection with Mr. Boulton at Soho. 
When this engine was in action, those Cornish gentlemen who were interested in 
the mines were invited to inspect its operation. The individuals who formed a 
deputation from the adventurers, for the purpose of observing this experiment, gave 
a very favorable report as to the effects of the patent engine with relation to the 
saving it made in fuel. 36 
30. This accredited account having reached Cornwall, the adventurers were not 
slow in testing the merits of the new invention by trial in their own county, and 
engines were immediately demanded there. 
The first erected by Watt in Cornwall was one with a cylinder 30 inches in 
diameter, fixed at Creegbraws, near Chacewater, very soon after Smeaton’s engine at 
Chacewater; probably about 1776. It worked there a few months, and was then 
removed to Wheal Busy, where it remained in action for some time afterwards. 
In 1777 the patentees erected three more engines, namely, at Ting-tang, Owan- 
vean, and Tregurtha Downs. 37 These were of larger dimensions ; two of them had 
cylinders 63 inches diameter, and were capable of working with a load of 11 or 
12 lbs. per square inch of the piston. 38 The first-named of these three, that at 
Ting-tang, was put up with the concurrence of one of the Hornblowers, who was 
engineer to the mine at the time. In Watt’s first engines, and in this among the 
number, the air pump and condenser were exhausted previously to starting by 
means of a small pump worked by hand, and, on the first trial, the engine suddenly 
started and killed the man who was working the pump. Watt, who was present at 
the time, afterwards added the arrangement for bloiving through, in order to produce 
a vacuum at starting, by condensation. 
36 Stuart’s Anecdotes of Steam Engines, page 263. 
37 Appendix to Pryce’s Mineralogia, added for the purpose of describing Watt’s improved engine, then 
newly introduced. 
33 Letter of the Patentees to Smeaton, published in Farey on the Steam Engine, p. 330.