Presently the crowd sees rubber-coated, helmeted men with pipe and hose go through a window from which such dense smoke pours forth that it seems incredible that a human being could breathe it for a second and live. The hose is dragged squirming over the sill, where shortly a red-eyed face with disheveled hair appears, to shout something hoarsely to those below, which they understand. Then, unless some emergency arise, the spectacular part is over. Could the citizen whose heart beat as he watched them enter see them now, he would see grimy shapes, very unlike the fine-looking men who but just now had roused his admiration, crawling on hands and knees, with their noses close to the floor if the smoke be very dense, ever pointing the "pipe" in the direction where the enemy is expected to appear. The fire is the enemy; but he can fight that, once he reaches it, with something of a chance. The smoke kills without giving him a show to fight back. Long practice toughens him against it, until he learns the trick of "eating the smoke." He can breathe where a candle goes out for want of oxygen. By holding his mouth close to the nozzle, he gets what little air the stream of water brings with it and sets free; and within a few inches of the floor there is nearly always a current of air. In the last emergency, there is the hose that he can follow out. The smoke always is his worst enemy. It lays ambushes for him which he can suspect, but not ward off. He tries to, by opening vents in the roof as soon as the pipe-men are in place and ready; but in spite of all precautions, he is often surprised by the dreaded back-draft. I remember standing in front of a burning Broadway store, one night, when the back-draft blew out the whole front without warning. It is simply an explosion of gases generated by the heat, which must have vent, and go upon the line of least resistance, up, or down, or in a circle--it does not much matter, so that they go. It swept shutters, windows, and all, across Broadway, in this instance, like so much chaff, littering the street with heavy rolls of cloth. The crash was like a fearful clap of thunder. Men were knocked down on the opposite sidewalk, and two teams of engine horses, used to almost any kind of happening at a fire, ran away in a wild panic. It was a blast of that kind that threw down and severely injured Battalion Chief M'Gill, one of the oldest and most experienced of firemen, at a fire on Broadway in March, 1890; and it has cost more brave men's lives than the fiercest fire that ever raged. The "puff," as the firemen call it, comes suddenly, and from the corner where it is least expected. It is dread of that, and of getting overcome by the smoke generally, which makes firemen go always in couples or more together. They never lose sight of one another for an instant, if they can help it. If they do, they go at once in search of the lost. The delay of a moment may prove fatal to him.