which has heretofore
dominated the international trade of the world, is of a high grade.
American coal available for export is on the 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:

1. 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.

2. Larger use of smoke consumers and mechanical stokers.

3. Larger use of central heating plants, with higher efficiency than
many local plants.

4. Substitution of gas engines for steam engines, and improvement of the
steam engine.

5. 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.

6. 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.

7. More consumption at the collieries.

8. Larger use of powdered coal as fuel.

9. Improvement of force-draft furnaces.

10. Larger use of gas, a by-product of coal mining, and extraction of
other by-products.

11. More efficient transformation of peat and coal into power and light.

12. 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 hy