RECIPROCATING AND TURBINE ENGINES ON STEAMSHIPS. 189 
of 23 pounds corresponding to a drop in temperature from 240.1 to 126.26 
or 113.84 degrees. ‘The aggregate drop in pressure for the second and third 
stages or two-thirds of the total horse-power, is from 70 pounds absolute to 2 
pounds absolute, a drop of 68 pounds corresponding to a drop in temperature 
from 302.9 to 126.26 or 176.64 degrees. 
In the turbine the second or last stage, or two-thirds of the total horse- 
power, is obtained by a drop in the pressure from 35 pounds absolute to 1 
pound absolute, being a drop of 34 pounds corresponding to a drop in tem- 
eprature from 259.3 to 102 or 157.3 degrees. 
These pressures and temperatures are not given for the purpose of 
making any comparison between the economic performance of the recipro- 
cating engine and the turbine, for as a whole their economy was practically 
the same. The consumption of fuel of like quality was practically the same 
per horse-power with the advantage in favor of the turbine as between shaft 
and indicated horse-power, the volume of steam passing through the cylinders 
was practically the same as that passing through the rotors, yet 1,886 horse- 
power, slightly over one-third of the total, was developed with a drop of 
pressure of 110 pounds, corresponding to a drop in temperature of 70 degrees, 
consequently the mean temperature of the high pressure cylinder, with its 
small surfaces, would be about 35 degrees below that of the entering steam. 
In the second stage, 1,874 horse-power, slightly more than one-third, was 
developed with a drop of pressure of 45 pounds, corresponding to a drop in 
temperature of 62.8 degrees, consequently the mean temperature of the 
intermediate pressure cylinder would be about 31.4 degrees below that of 
the entering steam. In the third stage, however, 1,840 horse-power, 26 less 
than one-third, was developed with a drop of pressure of 23 pounds, corre- 
sponding to a drop in temperature of 113.84 degrees, consequently the mean 
temperature of the low pressure cylinder would be 56.92 degrees below that 
of the entering steam, which, taken in connection with the larger surfaces, 
accounts for the great loss in the last stage. The intermediate cylinder 
being steam jacketed would indicate that considerable re-evaporation took 
place in that cylinder. 
It is unfortunate that, if the exact point was known in the expansion 
of steam where on the one side the economy would be with the reciprocating 
engine and on the other with the turbine, yet that point might not be the 
best place to make the division. There are other matters such as maneuver- 
ing with reciprocating engines, propeller design and desirable arrangement 
in the available engine room space, that may render the best arrangement 
for steam economy not the best for general economy. 
I believe that the best result in steam consumption could be gained 
from having the terminal pressure for the reciprocating part of the engine 
power at or about 30 pounds absolute, or a little above the usual low pressure 
