Steam Engine. 
the condenser. In an engine working with the improve-^ 
meats which Iiave been just described, while the steam is 
admitted to one side of the pistoji in the smaller c}dinder, 
tlie steam on the other side has room made for its admis- 
sion into the larger cylinder on one side of its piston, by 
the condensation going on on the other side of the large 
piston which is open to the condenser ; and that waste of 
steam which takes place in engines worked only by the 
expansive force of steam, from steam jiassing the piston, 
is prevented ; for all steam that passes the piston in the 
smaller cylinder is received into the larger. In such an 
engine, where it may be more convenient for any parti- 
cular purpose, tlie arrangement may be altered, and the 
top of the smaller made to communicate with the top of 
the larger, and the bottom of the smaller with the bottom 
of the larger cylinder ; in which case the only difference 
will be, that when the piston in the smaller cylinder de- 
scends that in the larger will ascend, and while the latter 
descends the former will ascend ; which for some parti- 
cular purposes may be more convenient than the arrange- 
ment before described. 
2dly. As the difficulty of giving a proper degree of 
strength to large cylinders, and the cases for the same, 
which are to be exposed to the action of strong steam, 
increases in proportion as their size is augmented; instead 
of employing, besides the smaller cylinder or steam mea- 
sure, one cylinder only of large diam.eter in steam engines 
of great power, I sometimes prefer substituting for the 
latter cylinder two or more cylinders of smaller diameter, 
but of such dimensions that their capacity, and the area 
of the pistons worked in them, are equal to the area of the 
one piston, and tlie capacity of the one cylinder which 
otherwise would be necessary ; and such substituted cy- 
linders are made to communicate with each other, that 
they m.ay at ont and the same time receive and part wdth 
