383 
Steam E7igine. 
Ill his working without a lever and beam. Also 
Part of the steam previous to condensation is employ^ 
ed a second time in another cylinder, the piston of which 
is depressed by the atmospherCo In this second applica- 
tion it performs the office of an air pump, and adds to the 
total force of the machine, 
Mr. Hmmblower^ as may be seen by his patent w’hich I 
have inserted, early proposed the use of the steam in a se= 
cond cylinder previous to condensation ; which has also 
been adopted by Mr. Woolf, I do not find that any engh 
neer, has superceded the use of the beam previous to Mr» 
Sadler, But whether his engine is in vogue or not, I can? 
not say. There is no beam to the jx)rtable engine of Mr, 
Cleggs of which I have given a plate. The method of 
giving rotatory motion adopted by Messrs. Long and 
Hauto^ of Germantown, if it succeeds will also supercede 
the necessity of the beam. Their other principle, of giv= 
ing motion by the pressure of a colunm of water confin- 
ed in a pipe, has been used in France about the year 1731, 
and afterward in Cornwall : since that by Mr. R, Trevi- 
thick^ at the Druid copper mine near Truro, in Cornwall ; 
and has been applied to packing goods by Mr, Brama^ of 
London, See 1 Nich. Jour. Bvo. p, 161, 
Sthly. Mr. R, Trevethickh steam engine, seems con- 
structed on the plan of using steam at a very high tempe- 
rature, and letting it escape without condensation. The 
accident that happened to one of his engines, and of which 
i have given an account, has brought them into disrepute, 
to a certain degree, but 1 see no objection to the princi- 
ple, which may be applied with perfect safety if reason- 
able caution be used in the construction of the apparatus, 
and in working it. 
9thly. Portable steam lengines have lately become 
filshionable, E^att and Boulton make them of all si^es ! 
