116 THE WATT AND THE TREVITHICK ENGINES. 



The 63-inch was an open-top cylinder atmospheric 

 engine at Dolcoath Mine under the management of 

 Trevithick, sen.; and shortly after, in 1777 or 1778, 

 Watt's first engine was erected in Cornwall. 1 



In 1783 Trevithick, sen., gave Watt an order for a 

 patent engine for Dolcoath, in size similar to the old 

 Newcomen atmospheric, having a cylinder 63 inches 

 in diameter, that a working trial might be made be- 

 tween the rival engines. The Watt engine having 

 a cylinder -cover, with the patent air-pump and con- 

 denser, was known in the county as the Dolcoath 

 great 63-inch double-acting engine. Three steam- 

 engines were then at work in that mine : Trevithick 

 senior's Carloose (then called Bullan Garden) atmo- 

 spheric 45-inch cylinder, the atmospheric 63-inch 

 cylinder, and Watt's 63-inch cylinder double-acting 

 vacuum engine; all of which continued in operation 

 side by side for five years until 1788, when for a time 

 Dolcoath ceased to be an active mine. Trevithick, 

 jun., was then a boy of seventeen years. 



After ten years of idleness and rust, as if mourning 

 the death of Trevithick, sen., in 1798 Richard Trevithick, 

 jun., as engineer, and Andrew Yivian as manager, 

 induced shareholders to resuscitate the old mine. Fire 

 was again given to the voracious jaws of the boilers, 

 and the three engines recommenced their labours and 

 their rivalries. 



A year or two before this Trevithick had made 

 models of high-pressure steam-engines. Davies Gilbert, 

 in 1796, met him among other engineers, giving evi- 

 dence in the Watt lawsuits, when he mentioned his 

 ideas of an engine to be worked solely by the force of 

 steam. Watt had claimed such an engine in his patent 



1 See vol. i., p. 30. 



