Air as Fuel. By Owen C. D., Ross. (Spon.)-41r. Bess
himself with the inquiry into possible substitutes for coal. His capti- vating title is a not very clear way of setting forth one at least of the results at which he has arrived. The secondary title of his book runs as follows :—° Petroleum and other mineral oils utilised by carburetting air and rendering it inflammable." Not only could petroleum be imported—and petroleum is of very common occurrence elsewhere than in America—but the vast deposits of shale in this island could be utilised. "The following results," says Mr. Ross, " may be relied upon :—(1), The intrinsic calorific power of such oils for evaporative or steam purposes is several times greater than that of coal ; (2), the thermal effect or intensity of heat obtainable from them iu metallurgical operations requiring very high temperatures is still more favourable, and allows the efficiency of furnaces requiring such temperatures to be many times multiplied ; (3), illuminating gas of very superior quality may be obtained from them at much less cost, and with much greater convenience than from coal." If these statements can be proved, they are of great importance.