The alarm, moreover, is so arranged that the first beat of the gong draws a bolt fastening the horse's halter to the stall. The animals rush to their posts, the firemen slide down poles from the upper stories to the lower, through holes in the floors made for the purpose, and, every one smartly doing his duty, the horses are harnessed, and the engine or apparatus-van is fully ready to start through the open doors before the gong has finished striking--unless it be a very brief alarm. Four snaps harness the horses. The animals stand on the ground-floor by the sidewalls, facing the wheels of the engines and trucks. The harness is hung over the pole-shaft exactly above the place where the horses will stand, the traces being fastened to the truck; the hinged collar is snapped round the animal's neck, the shaft-chain is fastened with a snap, and two snaps fix the reins. One shake of the reins by the coachman detaches the harness from the suspenders, and away fly the horses. Arriving at the fire, the engine is attached to the nearest hydrant, and the delivery-hose is led off to the burning building. The hydrant is probably of the upright kind, standing up above the roadway level, though some cities use the hydrant below-ground, and covered with an iron plate. But, the water obtained and the engine ready, the method of attacking the fire at close quarters and inside the edifice is adopted if practicable; and, to accomplish this purpose, the firemen have to fight through blinding and suffocating smoke. For hours they may struggle, well-nigh choked and scorched, though scarce a flash of flame may be visible. To reach the seat of fire, doors are broken down, and even iron shutters opened; while hose is led upstairs, or down into cellars, in order to quench the flames at their source. Sometimes, however, on arrival at a fire, the chiefs realize that the conflagration has gained such hold that the firemen's efforts will be most usefully directed to prevent it from spreading. When the water has done its work, the fireman can usually turn it off by a relief-valve without recourse to the engineer, the complete control thus gained tending to prevent unnecessary damage by water. The American fire-brigades--or departments, as they are called--may be broadly divided into two classes: those of great cities, consisting of a paid staff of officers and men, devoting all their time to the service; and, secondly, those of smaller places, consisting of a staff of unpaid volunteers, pursuing their usual daily avocations, but agreeing to respond to fire-alarms;--these men, though unpaid, are generally exempt from service as jurymen and militiamen, and sometimes are permitted a slight abatement of taxation. Some brigades, again, consist partly of fully-paid firemen, and partly of volunteers.