CS ee 
Mechanical Theory of Heat to the Steam Engine. 195 
I have also carried out this calculation for the above special 
case, whereby I have obtained the values given in the table for 
Tr that is for the work done during the expansion by the unit 
of mass. The kilogram is selected as the unit of mass, and 
which 1 kilogram of water evaporates at the temperature of 
150° and under a corresponding pressure, the value 18700. 
t | 150° 25° 
| 
4 | 0 11800 | 28200 | 35900 | 49300 
é 18. We turn our atten- 
tion now tothe consideration 
125° : 100° 
75° | 50° 
om 
| 
| 
matic figure, which is only 
intended to facilitate the 
general view of the whole 
series of processes connected. 
with the action of a com- 
From this, a portion of the = = 
passes into the cylin- ; 
der B, and forces the piston to a certain height. Then the cylin- 
der is cut off from the boiler, and the steam contained in it, lifts 
the piston still higher b expansion. The cylinder is thereupon 
put into connexion with the space Cc, which shall represent the 
condenser. We shall assume with respect to this, that it is not 
kept cool by ee he gs water but by cooling from without, which, 
as above remarked, produces no important difference in the re- 
Sults, but simplifies the consideration of the subject, Let the con- 
D ee 
= 5 is the equivalent of work for the unit of heat, and the above number signi- 
fies that the quantity of heat which is able to warm 1 kilogram of water from 0° 
to 1°. when gg into mechanical work gives a quantity of work equal to 
