496 NEeKBETTI AMD ZAMBRA, HOLBOBN VIADUCT, B.C. 



" In the accompanying engraving [of the gyroscope (fig. 3073), A is a section of the 

 periphery of the wheel, A A, which is constructed with a very heavy rim or periphery, and 

 a light disc, B B, forming the arms by means of which the connection is made to the axis, 

 C C, of the wheel. This axis is hung or connected to a ring, D D, by means of gymbal 

 journals at a a ; this axis at each end being brought to a conical point, and dipping into the 

 conical recess made in the end of the bolts b ; which bolts being screwed, pass through the 

 brass hoop or ring, and are secured steadily by the jam-nut, d, in the position which permits 

 of the free revolution of the axis, C C. This ring, D D, again is hung or connected to the 

 brass ring, E E, by means of gymbal suspensions at e e. These gymbal suspensions are 

 constructed in the same way (with bolts and jam-nuts) as those described suspending the 

 axis C C, of the wheel A A. Again, this ring, E E, is suspended to the upper part, F F, of 

 the stand, by another pair of gymbals similarly to the others. The box, F F, or upper part 

 of the stand is provided with a prong, G, or long pivot, which dips into a socket on the top 

 of the lower part of the stand, H. The apparatus so made is thus capable of the following 

 motions : The wheel, A A, is capable of revolution on its axis, C C, within the ring, D D 

 the ring, D D, including the wheel A A, is capable of revolution within the ring, E E. round 

 the gymbal suspensions, e e; the ring, E E, is again capable of revolution within the box, 

 F F, or upper part of the stand, round the gymbal suspensions that connect it to the frame 

 or stand ; and finally the whole apparatus is susceptible of revolution horizontally on the 

 pivot, G, which is inserted into the socket of the stand, H." 



The same journal then goes on to say : " With the apparatus so constructed a variety of 

 beautiful experiments can be performed, of which the following are the more interesting. 

 Kemove the ring, D D, carrying the wheel, A A, from the machine, set the wheel, A A, in 

 rapid motion, which can be done by winding a piece of twine round the axis of the wheel, 

 A A, and while holding the ring, D D, firmly in the hand, pull the twine violently, so as to 

 uncoil it from the axis, C C ; suspend the ring, D D, by a piece of line attached to itself, or 

 what is better, to the projecting head of the bolt which is outside of the ring at the gymbal 

 journal ; and so long as the velocity of the wheel, A A, exceeds a certain amount, the ring, 

 D D, will stand horizontally, though suspended on one side, or it will remain in any position 

 forming an angle with the horizon in which it may be placed ; and while so suspended will 

 slowly revolve round the suspending twine as a centre of motion. Thus the revolving 

 motion of the mass of the wheel and axis resists the action of gravity on the mass, both of 

 the matter which is in motion and on that which is at rest. 



" Another experiment is as follows : Place the ring, E E, perpendicular, the ring, D D, 

 at right angles to it ; set the wheel, A A, in rapid motion in the same way as before, and 

 assuming that while the machine is at rest it is in exact equilibrium, suspend while it is in 

 motion a small weight on the projecting head of the bolt, which forms the axis of the wheel, 

 and a horizontal revolution of the whole mass round the pivot centre of the stand will take 

 place. Suspend now a heavier weight at the other end of the axis of the wheel, and the 

 motion will be reversed ; that is, if with the light weight the revolution took place to the 

 right or left hand, it will, after the addition of the heavier weight at the opposite end, 

 revolve to the left or right hand, the direction being determined by the direction in which 

 the wheel, A A, revolves. 



"A third very interesting experiment is the following: When the whole machine is 

 at rest, if a stand be slowly turned round on the table, the whole mass will turn with it, the 

 weight of the machine causing sufficient friction on the pivot to produce this effect ; but set 

 the wheel in rapid motion as before, and the stand may be turned either way without 

 disturbing the upper part of the machine, or altering the absolute direction of the axis of 

 rotation. Thus, as with the pendulum experiment, can be shown the actual revolution of 

 the earth, seeing that as the revolution of the earth takes place, it slowly revolves round 

 under the gyroscope, the axis of which retains the same absolute direction in space. Instead 

 of the ring, D D, being used to carry the axis of the wheel, A A, a semi-sphere is sometimes 

 substituted, and in this form if the cup or semi-sphere be carried in the hand, the resistance 

 which the moving mass offers to any change in the direction of the axis of rotation opposing 

 any horizontal or perpendicular angular motion in the axis, gives the sensation as if the 

 inanimate matter possessed life and_will of its own." 



