202 R. Clausius on the Application of the 
warming and evaporation, has much lower temperatures than 
the fire, and that thus the heat which is communicated to it 
must pass from a higher to a lower temperature, there is in V 
an uncompensated transformation which is not reckoned in the 
calculation, which with the reference to making the heat useful 
- occasions a great loss. The work which can be obtained in the 
steam engine from the quantity of heat, m,7,+Mce(7,—T,)= Q, 
is, as we see from equation (27), somewhat smaller than 
Qa, T, - To 
A; See = 
If therefore the same quantity of heat could be communicated 
to a variable body at the temperature of the fire, which may 
called 7’, while the temperature corresponding to the subtrac- 
_ tion of heat, remains as formerly 7, the work possibly to 
obtained in this case according to equation (4) would be repre- 
sented by 
oS ae 
—ar-. 
A 
In order to be able to compare the values of these expressions 
in some examples, let the temperature ¢, of the condenser be » 
fixed at 50° C., and let the temperatures 110°, 150°, and 180° C. 
be assumed for the boiler, of which the first two correspond — 
about to the low pressure engine and to the common high pres- 
sure engine, and the last is to be regarded as about the limit of © 
the temperatures engines in practice. For these 
in steam . 
cases, the fraction depending on the temperatures has the follow: - 
ing value. 
ty | 110° 150° 180° | 
| 
fF rae 0-157 | 0-286 | 0287 
‘ 
“g 
er ae sa oil 
Whereas the corresponding value for the temperature of / of 
° ©. is 0-74 z 
the fire, if we assume this only at 
25. It is hereby easy to perceive what S. Carnot and after — 
him many other authors have asserted, that in order to arrange 
portant advantage over steam engines, when we succeed in mak- : 
ing them work at considerable higher temperatures than steam — 
tures. 
ever also be obtained with overheated steam, since as soon 
the vapor is separated from the liquid, we may heat it still fur- : 
