If a lump of coal is larger than a man's fist it is cracked up before being thrown into the furnace. As the stoker swings his filled shovel toward the opening door his trained eye is looking for two things--a pronounced hollow in the bed of coals, or a spot in which the duller glow tells him the combustion is considerably advanced. If neither is visible he gives his shovel a very sharp side flirt and spreads its contents just as widely and evenly as he possibly can. If he observes a hollow he endeavours to even it up with fresh coal. A burnt-out spot also receives fresh fuel, and if there is evidence of the formation of a crust of "clinker," this may be marked for a subsequent cracking up with the "slice," a long steel bar which serves the purpose of a poker. Every effort is bent toward maintaining a smooth, evenly burning bed of coals under all of the boiler. Automatic regulation of stoking is no new thing in warships, and was even in use on the latest of the Atlantic liners running before the war. The machine most commonly in use by the British is the "Kilroy," and its object is to raise a given amount of steam with a minimum of coal and physical effort. Thoroughly to understand its workings one should go first to the engine-room, from where it is regulated. The order for a certain speed is sent from the bridge to the engine-room, and the engineer sets his "Kilroy" so that the stoking shall proceed at a rate calculated to produce the necessary steam. The dial of the machine is numbered from "3" to "12," and the number he turns the indicator to--say "7"--rings up the numbers of the furnace doors in the boiler-room at a rate which will ensure that each shall be stoked every seven minutes. The number of shovelfuls of coal to be thrown in at each stoking is determined by consulting first the telegraph from the bridge (which registers in both the engine-room and stokehold) and a table which each stoker knows by heart. The dial of the telegraph is marked as follows: "Keep Steam," "Stop," "Slow," "Half Speed," "Full Speed," "More Steam." The table referred to gives the number of shovels to be thrown on at each stoking to fulfil the direction on the telegraph. Thus "Slow" calls for from two to three shovels of coal, "Full" four to six, and "More Steam" from six to eight. This plan gives perhaps the most perfect control of stoking possible without mechanical handling of the coal, and that is hardly practicable on shipboard. Practically all modern coal-burning ships carry a small supply of oil fuel, which is, however, generally used very sparingly and kept for raising steam pressure quickly in great emergency.