Fossil fuels are, without a doubt, scarce.
In small stoves for warming and for cooking, petroleum presents some advantages over other fuels, in that there is no chimney to sweep, and if well managed no unpleasant fumes, and the stoves are easily portable.
Accord Table 111.-Composition of Fuels (assuming Carbon = Ioo).
Charcoal, coke or anthracite coal are the fuels generally used in slow combustion heating stoves.
Thus in 1906 the salt monopoly was abolished at a cost to the revenue of 175,000, while the reduction of import duties on coal and other fuels, live-stock, &c., involved a further loss of 1I8,000, and an increase of over 1,000,000 in expenditure was budgeted for.
This has led to the estimation of sugar by means of the polarimeter, and of the calorific power of fuels, and the valuation of ores and metals, of coal-tar dyes, and almost all trade products.
Oils are powerful fuels, but the high price of refined petroleum, the oil generally preferred, precludes its widespread use for many purposes for which it is suitable.
Ricardo's paper on" The Influence of Various Fuels on the Performance of Internal-Combustion Engines,"published in 1921.