8 
THE CORNISH PUMPING ENGINE. 
3rd. To lift water 15 fathoms, or 90 feet, would have required steam of a 
pressure of upwards of 30 lbs. on the square inch above the atmosphere (sup 
posing 20 or 30 feet of the lift to be performed by condensation), involving a 
serious risk and danger to the works and the men engaged in them from the 
possibility of the boilers bursting ; particularly as in those days the vessels 
were not so well made as at present, and as Savery does not seem to have been 
acquainted with the use of the safety valve, which was subsequently added to 
his engine by Dr. Desaguliers. 
4th. The expenditure of coals with Savery’s engine was very considerable ; 
so that no adequate advantage of economy was offered to compensate for 
the inconveniences of its use, and the outlay of capital required for its esta 
blishment. This objection had particular force in Cornwall, where coals were 
dear; and it was a long time before even the atmospheric engine, which, in 
dependently of its other advantages, performed twice or thrice the work with 
the same quantity of fuel, 10 was deemed sufficiently economical to be brought 
into general use. 
11. Although, from these causes, Savery failed in the application of his engine to 
draining mines, although his machine has since been entirely superseded by a better, 
and although what he did contributed but little towards the invention or improve 
ment of the engine now in use, we must be careful not therefore to deny him the 
great degree of honour he is justly entitled to as an inventor, and the high place his 
name will ever hold in the history of the steam engine. 
It has been well remarked, 11 that when a comparison is made between Savery’s 
engine and those of his predecessors, the result will be in every respect favorable 
to his character as an inventor and as a practical engineer ; all the details of his 
invention are made out in a masterly style, and accidents and contingencies are 
provided for, so as to render it a real working engine ; whereas De Caus, the 
Marquis of Worcester, Sir Samuel Morland, and Papin, though ingenious philo 
sophers, only produced mere outlines, which required great labour and skill of 
10 We are now in ignorance of the consumption of fuel in Savery’s original engines. Savery himself 
says, “ the quantity could not be easily ascertained, because of the different nature of the several sorts of 
coals.” Bradley, in his ‘ New Improvements of Planting and Gardening,’ states that an engine erected 
at Cambden House would raise up (58 feet high) four of the receivers full in one minute, = 52 gallons, 
which is 3120 gallons an hour. He then says the quantity of coals required for each working was about half 
a peck ; but he does not add how long each working lasted. This passage has sometimes been erroneously 
transcribed. 
Smeaton tried two engines put up at Manchester in 1774 on Savery’s plan improved, and found the 
duty 5 to 5f millions. (See Farey, p. 125.) 
11 Farey on the Steam Engine, page 108.