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 346½lbs. of coal; which gives rather less than 6½lbs. 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 40¾lbs. of water, at the temperature 55 degrees, boil.

But in the foregoing experiment, 1 lb. of coal was consumed in making 6½lbs. 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 6½to 40 3/4, or instead of 450½lbs. of coal, 71¾lbs. would have done the business; and, instead of costing 3s. 2 1/2d., they would have cost less than 6¼Irish 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
0½ lb. of ginger,
------
making in all 3992½lbs.,
been made into a soup,
instead of being made into Calecannon, this, at 1¼lb.
(equal to one pint and a
quarter), the portion would
have served to feed 3210 persons.

I shall think myself very fortunate, if what I have done in the prosecution of these my favourite studies, should induce ingenious men to turn their attention to the investigation of a science, hitherto much neglected, and where every new improvement must tend directly and powerfully to increase the comforts and enjoyments of mankind.

This the end of Volume 1 of Count Rumford's Essays