Our creature has no regular meals, especially if he is one of the fast kind; but a grimy nurse stands by, and, opening his mouth every few minutes, crams in a few spoonfuls of the black pudding. The natural consequence is more or less indigestion and inequality of strength. We have not yet taken full advantage of the laws of combustion, or adapted our apparatus to the peculiarities of the best and cheapest fuel. Nature manages more wisely in her machinery. Combustion, the union of fuel with oxygen, ceases for want of air as well as for want of fuel. In the case of fuels compounded of carbon and hydrogen, if the air be withheld when the mass is in rapid combustion, the heat will cause a portion of the fuel to pass off by distillation, unconsumed, and this portion will be lost. But from the best anthracite, which is nearly pure carbon concentrated, if oxygen be entirely excluded, not much can distil away with any degree of heat. The combustion of this fuel, therefore, admits of very easy and economical regulation, by simply regulating the supply of air. When the air is admitted at all, it should be admitted above as well as below the fuel, so that the carbonic oxyde that is generated in the mass may be burned, or converted into carbonic acid, over the top. Why, then, should not the iron horse, before leaving his stable, take a meal of anthracite sufficient to last him fifty or one hundred miles? Let him swallow a ton at once, if he need it. Before starting, let the temperature of the mass in the furnace be got up to the point where the combustion will go on with sufficient rapidity for the required speed by simply supplying air, which should also be fed as hot as possible. This done, the engineer throughout the trip will have perfect control of his force by means of the steam-blast and air-openings. There will be no smoke nuisance, the combustion being complete so far as it takes place at all. There will be no need of loading the furnace with firebrick to equalize the heat,--the mass of incandescent fuel serving that purpose; and no waste or inequality will occur from opening the door to throw in a cold collation.