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Description of the Rotascope: 275 
posed by the persistency of the wheel. If at this moment the pivot 
be released from the screw, the whole system, composed of the two 
weights, the frame and ring 3, will be made to revolve by the gravity 
of the weights, while the ring 2 remains pertinaciously fixed in its 
position, until the wheel has had time again to invert its axes. ‘This 
time will be greater or less, according to the greater or less velocity 
of rotation in the wheel, compared with the size of the weights hang- 
ing over the pullies. : 
5. Fix the ring 3 in a vertical position by means of a grooved 
wedge moving in and projecting above the lower piece of the frame 
P; wind up two cords about the pullies on ring 1, and attach a 
weight of a few ounces to each; then set the wheel in rapid motion, 
tnd abandon it to the action of those weights. The ring 2 will re- 
volve in a certian direction about its vertical axis, until the wheel has 
‘ome to revolve in the opposite direction, then the direction of the 
mg will be inverted ;—and if the weights continue their action 
trough several revolutions of the ring 1, an inverse motion in the 
ting 2 will take place at each semi-revolution of the former. If in- 
stead of revolving about its vertical axis, the second ring be attached 
‘ad kept at right angles to the plane of No. 3, by cords leading to 
the side pieces of the frame, these cords will exhibit alternately a 
ne tension, as the first ring performs its successive semi-revo- 
ns. 
6. Hang a weight of one or two pounds on the ring 1, raise it up 
il that ting is in a horizontal position, (the third ring being still in its 
"etieal position,) and tie a small cord or thread from ring 1 opposite 
Othe end of the axis, down to the lowest point of circle 2. This 
thread must be strong enough to support the weight before-mentioned 
the opposite end of the axis. Now give the wheel a rapid rota- 
i; there will be no tendency in ring 2 to revolve horizontally. 
tif we cut or burn off the string, so as to allow the weight to act 
by its whole gravity at the opposite end, the second ring will begin 
revolve horizontally with a rapidity proportioned to the weight 
“hen the velocity of the wheel is given. 
1. Place the second ring horizontal, hang a weight. to its periphe- 
1; posite to the axis of circle 3; then having set the wheel in 
“on; raise the weight up to a level with the centre of the wheel, 
even higher, and let it rest upon the momentum of the wheel, until 
latter has changed the position of its axis by causing ring 1 to 
m half a revolution ; then the weight will descend and oscillate 
