whole of considerably lower grade, being higher in volatile matter. Unless this coal is beneficiated at home, it can replace the English coal in the export field only at increased cost of transportation and lower efficiency in use. The time may come when it will be desirable to ship lower-grade coals long distances; but when the two factors of conservation are considered—the intrinsic qualities of the coal, and the efforts necessary to utilize it—it would seem to be conservational at this stage to ship to long distances only the coal which nature seems specially to have prepared for this purpose.
(E) Utilization of coal. Conservational proposals of this kind are:
- Substitution of retort coke-ovens for beehive ovens, to save not only a larger quantity of coke but also valuable by-products (see pp. 118-119). Additional improvements in coking ovens may make possible the manufacture of some sort of coke from a much wider range of bituminous coals than can be used at present.
- Larger use of smoke consumers and mechanical stokers.
- Larger use of central heating plants, with higher efficiency than many local plants.
- Substitution of gas engines for steam engines, and improvement of the steam engine.
- Improvement in methods of smelting, leading to larger output of metal per ton of coke used. Also the development of electric smelting for certain metals.
- More careful study and classification of the qualities of coals, in order to avoid use of higher-grade coals where inferior coals would serve the purpose.
- More consumption at the collieries.
- Larger use of powdered coal as fuel.
- Improvement of force-draft furnaces.
- Larger use of gas, a by-product of coal mining, and extraction of other by-products.
- More efficient transformation of peat and coal into power and light.
- The possible use of oil flotation to eliminate foreign mineral matter.
Most of the conservation measures above proposed have already been applied with good results, and with promise of large results for the future. The stimulus has come largely from self-interest. War conditions in some ways aided and in others hindered these developments. One of the conspicuous gains was the building of many by-product coke plants, under the necessity of securing the nitrates and hydrocarbons for munition and other purposes.
(F) Substitutes for coal as a source of power. Some of the more prominent measures along this line which have been discussed are:
- Larger use of water power. This has sometimes been popularly assumed to be, at least potentially, a complete solution of the problem; but nevertheless it has its distinct limitations.