When the furnace-doors are opened, thirsty tongues of fire gush out, blue spirals of gas spin and reel over the bubbling mass of fuel, and great sheets of flame suck half-burnt carbon over the quivering fire-wall into the flues. With averted heads and smoking bodies the stokers shoot their slice-bars through the melting hillocks, and twist and turn them until they undulate like serpents. The iron tools blister their hands, the roaring furnaces sear their bodies; their chests heave like those of spent swimmers, their eyes tingle in parched sockets—but work they must, there is no escape, no holiday in this maddening limbo. Steam must be kept up, or perhaps a cruel record must be lowered. Facing the furnaces, the hollow up-scooping of the stoker’s shovel echoes stridently on the iron floor, and these speed-makers pile coal on coal until the fire fairly riots, and, half blinded, they stagger backward for a cooling respite. But it is only a moment at the best, for their taskmasters watch and drive them, and the tale of furnaces must do its stint. The noise and uproar are deafening; coal-trimmers trundle their barrows unceasingly from bunker to stoke-hole, or, if the ship’s motion be too great for the wheels, carry it in baskets, and during the four long hours there is no rest for those who labor here. In the largest ships the engineer force numbers one hundred and seventy men, and in vessels with double engines these are divided into two crews with a double allowance of officers for duty. One engineer keeps a watch in each fire-room, and two are stationed on each engine-room platform. Watches depend upon the weather, but, as a rule, the force, officers and men, serves four out of every twelve hours. Should, however, the weather be foggy or the navigation hazardous, the service may be more onerous; for then officers stand at the throttles with peremptory orders to do no other work. In relieving each other great care is taken; those going on the platforms feeling the warmth of the bearings, examining the condition of the pins and shafting, testing the valves, locating the position of the throttles, counting the revolutions, and by every technical trial satisfying themselves before assuming charge that all is right. In the stoke-hole the same precautions are taken, the sufficiency and saturation of the water, the temperature of the feed, injection, and discharge, and the steam-pressure being verified independently by both officers.