Fig. 891.—The house swing.
Fig. 892.—The house trapeze.
The bar, B (see fig. 892), is of wood, terminating in screws enclosed in the grooves of the wood, at the extremity of which indiarubber discs are fixed (C and C´). When the bar is placed between the side posts of the open door and with the indiarubber in contact with the sides, the bar, B, is vigorously screwed in the direction of the arrow, and this motion is transmitted to the indiarubber discs which press against the door, and the apparatus remains fixed. The trapeze cords, or the swing ropes, can be fastened to the bar with hooks, as shown in the illustration, and the solidity and safety of the bar may be tested by putting heavy weights upon the ropes before venturing upon the swing, or trapeze. Even violent exercises may be indulged in without any fear of falling if the bar be firmly screwed against the sides of the door.
Simple Toys.
The accompanying illustration shows us a circlet of paper, very thin, fastened upon a frame, with paper wings fixed to the radii. This “screw” fashioned wings and the circlet can be kept up in the air by means of a hand screen. The effect will be observable in the rapid revolution of the little paper wheel, which must be very light and thin. (See fig. 893.)
Fig. 893.—The paper wheel.
There are many toys which can be controlled by the use of indiarubber springs. The bicyclist in the cut (fig. 894) is an instance in point. He turns around a pivot, and the tension of the spring keeps the machine in its place.