‘ MECHANICAL ACTION OF HEAT. 185 
4 The data in this case for calculating the power, are, 
P, = 8468 lb. per square foot. 
V,=7-584 cubic feet for one lb. of steam. 
P, V,=64221 Ib. raised one foot. 
pia Whence s=8) =5:944. 
Maximum possible effect of one pound of water, 
=P, V,x7 (1 is (5) ‘) =115600 Ib. raised one foot. 
Being the mechanical equivalent of 92°:3 centigrade degrees applied to one 
pound of liquid water at 0° C. ; or. 
92°:3 Ky 
Maximum possible effect of one cubic foot of water, 7,225,000 lb. raised one foot. 
In order to calculate directly the heat converted into power, we have, 
i =C+144°1 cent. 7, =C+81°7 
=549°-7 K,, 
Ae “568° ‘7 Ky = heat expended in the boiler. 
1—m='14 nearly = proportion of steam liquefied during the expansion. 
The heat converted into mechanical power, as calculated from these data, is 
found to be, 
91°-6 K,, 
differing by only 0°-7 from the amount as calculated from the power produced. 
The direct method, however, is much less precise than the other, and is to 
be regarded as only a verification of the general principle of calculation. 
The heat rendered effective, in the above example, is o “a? OF less than one- 
sixth of that expended in the boiler. 
As a second example, I shall suppose the steam to be produced at a pressure 
of eight atmospheres, and to expand to that of one atmosphere. In this case, 
; P, =16936 lbs. per square foot. 
q V,=403 cubic feet per Ib. of steam. 
enn): P, V,=68252 lbs. raised one foot. 
Be diate feian hash 
Pee s=5:657=8 
Maximum possible effect of one pound of water, 
% ; 1 
¥ =P, V,x6(1- (5) 6) =119,042 Ib. raised one foot: 
a Being the equivalent of 95°°8 K,, (Centigrade). 
Maximum possible effect of one cubic foot of water = 7,496,375 Ib. raised one foot. 
The data for calculating directly the heat rendered effective are, 
7,=C+170°9 cent. 7, =C+100° 
L,=537° K 
H,, ,=558"6 K,, = heat expended in the boiler. 
1—m='148 nearly = steam liquefied during the expansion. 

