Expence for fuel, 17 pecks of coal, at 1L. 3s. 3d. per ton, -- -- -- -- -- 0 3 2 1/2 ------------- Total L. 7 19 11 1/2
With this kind of food there is no allowance of bread, nor is any necessary.
It would be hardly possible to invent a more nourishing or more palatable kind of food, than Calecannon, as it is made in Ireland; but the expence of it might be considerably diminished, by using less butter in preparing it.
Salted herrings (which do not in general cost much more than a penny the pound) might be used with great advantage to give it a relish, particularly when a small proportion of butter is used.
In this experiment, 273 gallons of water, weighing about 2224 lbs. avoirdupois, and being at the temperature of 55 degrees, was made to boil, (in two hours and 32 minutes,) with the combustion of 346 1/2 lbs. of coal; which gives rather less than 6 1/2 lbs. of water, to each pound of coal consumed; the water being heated 157 degrees, or from 55 to 212 degrees.
According to my experiments, 20 lbs. of water may be heated 180 degrees, (namely from 32 degrees the freezing point, to 212 degrees the temperature of boiling water,) with the heat generated in the combustion of 1 lb. of pine-wood; consequently, the same quantity of wood (1 lb.) would heat 23 lb. of water 157 degrees, or from 55 to 212 degrees.
But M. Lavoisier has shown us by his experiments, that the quantity of heat generated in the combustion of any given weight of coal, is greater than that generated in the combustion of the same weight of dry wood, in the proportion of 1089 to 600; consequently, 1 lb. of coal ought to make 40 3/4 lbs. of water, at the temperature 55 degrees, boil.
But in the foregoing experiment, 1 lb. of coal was consumed in making 6 1/2 lbs. of water boil; consequently, more than 5/6 of the heat generated, or which might with proper management have been generated in the combustion of the coal, was lost, owing to the bad construction of the boiler and of the fire-place.