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. Had the construction of the boiler and of the fire-place been as perfect as they were in my experiments, a quantity of fuel would have been sufficient, smaller than that actually used, in the proportion of 6 1/2 to 40 3/4, or instead of 450 1/2 lbs. of coal, 71 3/4 lbs. would have done the business; and, instead of costing 3s. 2 1/2d., they would have cost less than 6 1/4 Irish money, or 5 3/4d. sterling, which is only about 1/3 per cent. of the cost of the ingredients used in preparing the food, for the expence of fuel for cooking it. These computations may serve to show, that I did not exaggerate, when I gave it as my opinion, (in my Essay on Food,) that the expence for the fuel necessary to be employed in cooking ought never to exceed, even in this country, TWO PER CENT. of the value of the ingredients of which the food is composed; that is to say, when kitchen fire-places are well constructed. Had the ingredients used in this experiment, viz. 2234 lbs. of water 1615 lbs. of potatoes, 98 lbs. of butter, 14 lbs. of onions, 40 lbs. of salt, 1 lb. of pepper, and 0 1/2 lb. of ginger, ------ making in all 3992 1/2 lbs., been made into a soup, instead of being made into Calecannon, this, at 1 1/4 lb. (equal to one pint and a quarter), the portion would have served to feed 3210 persons. But if I can show, that in Ireland, where all the coals they burn are imported from England, a good and sufficient meal of victuals for 3210 persons may be provided with the expence of only 5 3/4d. for the fuel necessary to cook it; I trust that the account I ventured to publish in my first Essay, of the expence for fuel in the kitchen of the Military Workhouse at Munich, namely, that it did not amount to so much as 4 1/2d. a day, when 1000 persons were fed, will no longer appear quite so incredible, as it certainly must appear to those who are not aware of the enormous waste which is made of fuel in the various processes in which it is employed.