The jumping-sheet is made of the best strong canvas about 9 feet square, and strengthened with strips of webbing fastened diagonally across. The sheet is also bound round at the edges with strong bolt-rope, and is furnished with about a score of hand-beckets, or loops. If at a fire all other means of rescue be unavailable, the sheet should be brought into use. Volunteers, if necessary, should be pressed into the service, and instructed to stretch out the sheet by the beckets, holding it about two feet or so from the ground. They should grasp the becket firmly with both hands, the arms being stretched at full length, their feet planted well forward, but their heads and bodies thrown as far back as possible. Even then the volunteers will probably find great difficulty in maintaining the sheet, and preventing it from dashing on the ground. If possible, a mattress or pile of straw or some soft object should be placed on the ground beneath the sheet. The uninitiated have no idea of the weight of a body suddenly falling or jumping on to the sheet from a great height, and this occasion is one for the putting forth of all the strength of body and determination of will of which a man may be capable. But, now the sheet is being folded, and men are appearing on the roofs of the buildings above. A new exercise is beginning. Rescue by rope is now to be practised, and long threads of rope begin to appear. Imagine yourself a fireman on the top of a burning house, with smoke and flame belching out of the windows below, and agonizing screams for help ringing in your ears. No fire-escape is near, or, if near, not available; for it sometimes happens that persons cannot be rescued by ladders, and the staircase is a mass of flames. What would you do? It is then that the firemen use the chair-knot, or, speaking popularly, they try rescue by rope. Every engine carries excellent rope of tanned manilla, and the fireman carries a rope about his body. Quickly the ends of the rope are fastened to two points, one on either side of the window--to a chimney-stack, if possible; then, as sailors know how, by means of what is called a "tomfool's knot," loops and knots are made in the rope--one loop to be slung under the arms, and the other to support the knees, and together forming a sort of chair. Speedily the loops are adjusted round the person to be rescued, and then he is gradually lowered to the ground. A guiding-rope has been attached, and thrown to the men below, and is used by them to steady the person's descent, to prevent him from bobbing hither and thither, or to draw him out of reach of the flame and smoke. This exercise being over, there is a rattle and a clatter, and into the yard dashes a horsed fire-escape. The men pounce upon it at once, and in a trice whip it off its carriage and wheel it to the building. The present escapes are great improvements on the old forms, and two men can extend it with ease.