8-5 
Steam Engine. 
heads or notices of schemes, many of them obviously im- 
practicable, which at various times had suggested them- 
selves to his very fertile and warm imagination. No 
contemporary record exists to illustrate or verify his de- 
scription of the contrivance which we presume to call a 
steam-engine, or to inform us where, and in what man- 
ner, it was carried into effect ; though it is evident, from 
his account, that he had actually constructed and worked 
a machine that raised water by steam. His description 
of the method is short and obscure ; but inclines us to 
think, contrary to what many have supposed, that the 
force of his engine was derived solely from the elasticity 
of steam ; and that the condensation of steam by cold, was 
no part of his contrivance. This last, we believe, was the 
invention of Captain Savary, who, in 1696, published an 
account of his machine, in a small tract entitled the Mi- 
ne fs Friend, having erected several engines previous to 
that period. In these engines the alternate condensation 
and pressure of the steam took place in the same vessel in- 
to which the water was first raised, from a lower reservoir, 
by the pressure of the atmosphere, and then expelled into 
a higher one, by the elastic force of strong steam> 
Steam, it must be observed, was thus employed merely 
to produce a vacuum, and to supply the strength that was 
applied, for a like effect, to the sucker or piston of an or- 
dinary pump ; and it was a great step to have discovered 
a method of bringing the air to act in this manner by the 
application of heat to water, without the assistance of me- 
chanical force. 
The next essential improvement was made by New- 
comen, for which he obtained a patent in 1705. It con- 
sisted in separating the parts of the engine in which the 
steam was to act, from those in which the water vv^as to be 
raised; the weight of the atmosphere being employed 
OQly for the purpose of pressure, and the steam for that 
