Coal-dust As Fuel

The Chinese have for ages been in the habit of. mixing dust trom the coalinines witli clay and bitumen, and also with refuse matter, and such artificial fuel is in China an article of considerable traöic. The methoda introduced in Western Europe of utilizing the dust of mineral coal and of charcoal are nearly all bascd on the principie of making these substances cohere by thoroughly incorporatiug them with tar or pitch, and then exposing the compound, when molded into blooks, in Borne cases to a ourrent of air to dry them, and in others to a high temperature in vessels gerving the purpose of retorts. The former mode of drying is employed for mixtures of charcoal-dust, tar, and similar substances, with tar or pitch, and the latter when refuse bituminous coal is used with about a quarter of its weight of pitch. At Blanzy, in France, the coal is separated from the slaty and pyritous articles, and then crushed and introduced into a circular metallic basin, which revolves horizontally in a reverberatory furnace, the üame of which passes under it. Hot tar or pitch is gradually let in upon the coal from a reservoir over the fire to the amount of seven or eight per cent., and the mixture is stirred by stutionary rakes attached to rods let down through the arohed cover. When sufficiently mixed, the materiuls are made to drop through the bottom into a reoeptacle, whence they are removed -while plastic to the moulds, and thore pressed by the hydraulic machine. There are vast quantities of ooal-dust lying as waste matei ial in the various coal-mines in this country, which might be utilizad by mixing with proportions of the coal tar of gas-works, and compre8sed into bricks by machiuery. There can be no doubt that fue! oould be furnished in tbis way at an