274 Description of the Rotascope. 



garded as its prolongation,) will be kept for some time horizontal ; 

 but though thus suspended, as if by some ra3'sterious agency, they 

 constantly perform a circuit which has a vertical, drawn from the 

 point of suspension, for its axis. If the velocity of the horizontal 

 revolution be diminished, the sustaining rod will incline downwards 

 more rapidly than W'hen left to itself, until at length it reaches the 

 position of rest. But if the velocity of that revolution be augment- 

 ed by any external force, the wheel and ring will rise in opposition 

 to gravity, until the rim of the wheel strikes the suspending cord. 

 The wooden rod will then have come to a position nearly vertical, 

 sustaining the wheel and ring at its upper end, but still continuing 

 the horizontal motion. This paradoxical appearance would continue 

 the longer by having a delicate metallic swivel link in some part of 

 the cord, which should prevent the twist that otherwise soon opposes 

 the horizontal motion, to such an extent as to depress the rod in the 

 course of a few minutes. It will be seen that the revolution in a hori- 

 zontal direction being the resultant of gravity, combined with the 

 rotary motion of the wheel, must become more rapid in proportion 

 as the velocity of the latter on its axis is diminished ; because the 

 force of gravity is then a greater component in the combined forces 

 which act upon the system. 



4. Having replaced the wheel and ring 1, in their connection with 

 the frame, set the latter on its pivot, upon the base B. Make the 

 circle or ring 3 fast in a vertical position ; apply cords to the pulley 

 on the axis of ring 2, and bringing the pullies p, p, to a proper ele- 

 vation, make them fast and pass those cords over them to sustain 

 weights. Having given the wheel a rapid motion, take hold of one 

 of the urns m, u, and cause the whole frame to revolve horizontally 

 on its pivot. As the persistency of the wheel in the plane of its mo- 

 tion, prevents the ring 2 from revolving, the motion of the frame will 

 gradually wind up the cords about the pulley. At the same time, 

 however, the ring 1 will gradually change its plane, and bring the 

 wheel to a position to obey the action of the weights. The portion 

 of cord which had been previously wound about the pulley will then 

 be uncoiled, and a considerable momentum communicated to the 

 system, composed of the rings 1 and 2, which will, if the tightening 

 screw t be made fast, again wind up the cord in the opposite direc- 

 tion about the pulley. As soon as the said rings, however, are again 

 deprived of their momentum, by the action of the weights, the latter 

 will again tend to produce a rotation in the ring 2, which will be op- 



