136 THE WATT AND THE TKEV1THICK ENGINES. 



the quantity of iron smelted. The promise that the 

 wages of one-half of the number of boiler firemen would 

 be saved, was understood. Trevithick's high-pressure 

 boilers replaced the Watt low-pressure, resulting in a 

 largely - increased quantity of iron from the greater 

 power and pressure of blast in the furnaces, and at one- 

 half the expsnditure of coal in the boilers : ten men 

 had been employed as firemen of the Watt boilers 

 during twenty-four hours ; with Trevithick's boilers, 

 five men did the work. 



The high-pressure puffer-engine, with an 18-inch 

 cylinder, working with 45 Ibs. of steam, rolled as much 

 iron as the two larger low-pressure vacuum engines of 

 Watt, of 24 and 27 inch cylinders, which together were 

 more than three times the size of the high-pressure 

 engine, and cost three times as much. 



At Stourbridge, as elsewhere, everyone was against 

 the new plan. The engineer in charge did not like it, 

 and the carpenters, smiths, and masons saw the end 

 of their occupation as engine erectors, if there was no 

 longer a necessity for foundations, well-work, &c., for 

 condensing water, and many other things, necessary 

 to complete a Watt engine ; while the high-pressure 

 puffer was no sooner unloaded than it was ready to 

 work. 



A great charm in Trevithick's character was his 

 freedom and largeness of view in questions of competi- 

 tion. He was then making three engines at Coalbrook- 

 dale, to be worked with high-pressure steam, combined 

 with the Watt air-pump and condenser ; and though 

 smarting from the contest with his great rival, yet 

 wrote, " I think it is better to make them ourselves, for 

 if we do not, some others will, for there must be a 

 paving 1 of coal by condensing. But with small engines, 



