(From the _Mechanic_.)
[Illustration: Fig. 149.]
The ordinary gyroscopic action takes place when the lever D is held, the
weight F being carried horizontally round the vertical axis, passing
through the pivots C C. When the wheel is not spinning, the weight F
turns the ring A A into the vertical position, so that the weight pulls
downwards in the vertical line passing through the centre of the wheel.
The parts carried by the lever D are then accurately balanced by means
of the adjustable weight H. The ring A A is next held, in the position
shown, by the thread G being hooked on the pivot screw opposite the
weight F. If now the ring B is turned round on the pivots C C, the
gyroscope or the weight H will preponderate accordingly as the weight F
is further from or nearer to the supporting point of the pillar E than
the centre of the wheel. Finally, spin the wheel, and throw off the
thread G. It will then be found that although the weight F, in being
carried round by the gyration, is continually altering its distance from
the point of support, the apparatus keeps in balance. The gravitation of
the weight F is _not_, as some think, annihilated or converted into
horizontal action, but still _tells_ fully, doing so, however, as though
acting at the centre of the wheel. If any of my readers should wish to
try this experiment, they must have the apparatus very carefully made;
and they must bear in mind that the conditions required for the
experiment cannot be maintained for many seconds, as the friction of the
pivots and other resistances cause the introduction of forces which,
slowly at first, but with increasing rapidity, change the relative
positions of the parts.—E. H.
[Illustration: Fig. 150.]