SCIENTIFIC RECREATION'S. 



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 trans- 

 mitted 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, 



Fig. 893. The paper wheel. 



fastened upon a frame, with paper wings fixed to the radii. This 

 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.) 



There are many toys which can be controlled by the use of indiarubber 

 springs. The bicyclist in the cut (fig. 894) is an instanqe in point. He 



