REFERENCES
Coal is King. Hewette.
Economical Burning of Coal Without Smoke. Bement.
Coal and Coal Mines. H. Green.
International Library of Technology. Vols. 37 and 38.
Reports of Geological Survey.
Report National Conservation Commission.
Conservation of Mineral Resources. (U. S. Report.)
Production of Coals in the U. S. in 1908. Advance chapters available.
[CHAPTER VI]
OTHER FUELS
WOOD
Wood, which was formerly the only fuel used in this country, has now largely given place to other fuels. In rural districts and in lumber regions it is still used extensively; but in the cities, larger towns, and manufacturing regions, it is not used in commercial quantities. Its use for power production is limited to the wood-working factories which have a large amount of waste lumber and which employ this by-product to furnish heat for steam boilers.
The wood used for fuel or for power usually represents what would otherwise be lost, the dead trees and the unmarketable timber of the farmer's wood-lot, the refuse of lumber regions or the waste of wood-working factories. So that the use of wood as fuel now generally means the conservation of our coal supply, and a use for the low-grade parts of the forest.
In some cases, however, farmers cut for fuel fine young trees that would grow into excellent timber. Liberal planting of trees so that wood shall become plentiful in all parts of the country will tend to bring about again a larger use of wood as fuel, which will thus once more become a factor in the saving of our coal. Every farmer should learn to save all valuable trees for lumber, and to use only undesirable ones for fuel.