Steam Engine, 
in view, a tight piston and a vacuous condenser ; that is 
to say, a condenser from which the atmospheric air is ex« 
eluded : to accomplish which it is made of as thin cop= 
per as it will admit, exposing a large surface to the water, 
then the steam internally comes in contact with the me» 
tal of the same temperature, and hence the condensation. 
We wish it were possible to put this grand design into a 
decided effect : but from some particulars we have ob- 
'' served in the doctrine of condensation, no method yet ex- 
plored will obtain so rapid a condensation as actual con- 
tact with the water : we do not account for this by an)r 
chemical affinity, but by the exposure of surface ; for the 
experiment has been tried to our satisfaction, that when 
the jet was not in a dispersive state, the condensation 
was tardy and inactive ; and if it were possible to dis- 
perse the jet into a mist, we should obtain the most prompt 
condensation possible. 
But still we do not conceive an instantaneous conden- 
sation is absolutely necessary ; for if it is performed du- 
ring the time of the required stroke, that is all which is 
wanted. We cannot say whether Mr. Cartwright .lias 
succeeded ultimately to this point or not. 
W e remember to have seen preparations for an appara- 
tus for this mode of condensing some years since, by an 
assemblage of taper pipes of about a quarter of an inch 
diameter, exposing a surface of between 90 and 100 feet 
to a 20-inch cylinder ; but an accident from a rude hand 
prevented its application for that time, and W’e do not 
think it was ever resumed. 
The packing of Mr. Cartwright’s piston is composed 
of a series of segments of brass, the arches of wffiich con- 
form exactly to the circumference of the cylinder ; these 
are to be laid on the verge of the piston so as to 
make one entire disk, then another and another stratum 
super stratum until the designed thickness is acquired : 
