Ash.............................................. 10.53 Hydrogen, oxygen, nitrogen, and sulphur.......... 7.18 ------ Total non-combustible..................... 43.79 Carbon, being useful combustible................. 194.46 ------ Total fuel................................ 238.25

Air per pound of carbon................................   17-1/8 lb. 
Time of experiment.....................................  4 h. 12 min. 
Water evaporated from 60 deg. into steam at 53 lb. pressure   1,620 lb. 
Heat lost by radiation and convection..................  70,430 units. 
Mean temperature of chimney............................    700 deg.  F.
"        "       " air................................     70 deg.  F.

No combustible gas was found in the chimney.

I will apply Carnot’s doctrine to this case.

Potential energy of the fuel with respect to absolute zero: 
Units.
239.25 lb. x 530 deg. abs. x 0.238 ...................... = 30,053
194.46 lb. x 17-1/8 x 530 deg. x 0.238,
the weight and heat of air....................... 420,660
194.46 x 14,544 units heat of combustion of carbon... 2,828,200
---------
Total energy 3,278,813
Heat absorbed in evaporating 26.08 lb. of water
in fuel............................................ -29,888
---------
Available energy.......................... 3,248,425

Temperature of furnace—­

   The whole of the fuel was heated up, but the heat absorbed in the
   evaporation of the water lowered the temperature of the furnace,
   and must be deducted from the heat of combustion.

Units. 
Heat of combustion...................................  2,828,200
"   " evaporation of 26.08 lb. water...............    -29,888
---------
Available heat of combustion..............  2,798,312

Dividing by 238.25 lb. gives the heat per 1 lb.
of fuel used................................... = 11,745 units. 
And temperature of furnace: 
11,745 units/(18.125 lb. x 0.238) + 530 deg.......... = 3,253 deg. 
Temperature of chimney 700 deg. + 460 deg................ = 1,160 deg. 
Maximum duty (3,253 deg. - 1,160 deg.)/3,253 deg............. = 0.643 deg.

Work of displacing atmosphere by smoke at 700 deg.: 
Cubic feet. 
Volumes of gases at 70 deg......................... = 228.3
" " " " 700 deg......................... = 499.8
-----
Increase of volume.................... 271.5

Units. 
Work done=
(194.46 lb. x 271.5 cub. ft. x 144 sq. in. x 15 lb.)
722 units ..................................... = 147,720
Maximum amount of work to be expected =
3,248,425 x 0.643.............................. = 2,101,700
Deduct work of displacing atmosphere............. = 147,720
---------
Available work........................ 1,953,980