THE CORNISH PUMPING ENGINE. 
19 
under the cylinder, and an extra one, constructed to collect and make use of the 
waste heat from the furnaces upon the works. This latter however being found a 
failure, it was removed after a very short use, and two new boilers of the same con 
struction and dimensions as the centre one were added, being fixed in low buildings 
on each side of the engine-house. These were found successful in furnishing the 
engine with steam. 33 
This engine supplied the place of two atmospheric engines formerly on the mine, 
one with a 64-inch and the other with a 62-inch cylinder, both 6 feet stroke. Mr. 
Smeaton reported that the duty of the new engine was greater than that of the two 
old ones, in the ratio of 7 to 4. 34 
After working a few years it was altered by Watt, who was paid a large sum 35 by 
the proprietors, as a composition for the use of his patent upon the works of the 
mine. 
28. Smeaton raised the average duty of the atmospheric engine from 7 to about 
10 millions. 
The duty of the Long Benton engine is stated by Mr. Farey to have been 
= 9,450,000, “ exclusive of friction.” 
Mr. Smeaton undertook that a large engine he constructed for Cronstadt should 
raise 24,300 tons of water 53 feet with 7\ chaldrons of coal, which is equivalent to 
performing a duty of 10,600,000. 
The duty of the Chacewater engine is not known, but after the side boilers were 
added it was probably equal to the average. 
Smeaton’s changes thus had the promise of being considerably advantageous to 
the Cornish miners; but before their beneficial effect could be extensively felt, they 
were thrown into the shade by the splendor of those greater improvements, the in 
troduction of which opened a new era upon mining operations, and laid the founda 
tion of the great and unexampled success which has since attended the application 
of steam power to this source of our national wealth and greatness. 
These improvements were, it is almost needless to add, the inventions of the 
immortal James Watt. 
33 This statement respecting the boilers was given by the late Mr. Movie, who was employed at the 
mine at the time Smeaton’s engine was erected, and recollected the circumstances well. 
34 For an explicit description, and drawings of the Chacewater engine, see Smeaton’s Reports; or 
Farey on the Steam Engine. 
35 M. Arago (Historical Eloge of Watt, English translation, page 77,) states this sum at 60,000 francs, 
= £ 2400 sterling; but I have been informed, upon the authority of Mr. Moyle, the agent, who paid the 
money, that it is overstated, and must have included other works, probably those of North Downs mine 
adjoining; the amount for Chacewater mine alone being £1000 per annum. Mr. Moyle well recollects 
paying a monthly instalment of £ 83. 6s. 8d.