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. × 530° abs. × 0.238 ...................... = 30,053
194.46 lb. × 17-1/8 × 530° × 0.238,
the weight and heat of air....................... 420,660
194.46 × 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