An elementary treatment of the theory of spinning tops and gyroscopic motion, by Harold Crabtree.

10

INTRODUCTORY CHAPTER

Scientifically constructed Gyroscope. Fig. xxII. represents
a scientifically made instrument.* The wheel AB which has
(for its size) a very heavy rim, is free to spin about its axle
XX', while the frame in which this axle is mounted can turn
about the axis YY. Finally, the frame in which YY' is
mounted can turn about the vertical pedestal ZZ', but at Z there
is a screw which can be tightened to prevent this turning.
H^s<AFIG. XXII.
Experiment 1. Suppose now that the wheel is free to turn
about all three axes, and that friction is so slight as to be
negligible. Let a good spin be given to the wheel in the
direction marked, and let a weight be suspended at X. It will
be found that, instead of the wheel tilting about Y'Y, it will
turn about ZZ' in the direction indicated. But if the screw
at Z is tightened the revolving wheel will at once turn over
about Y' Y.
If, when the wheel is free to turn about all three axes, we
apply at X a force which is more easily removed than the
weight, such as the pressure of a finger, it will be found that,
when the rate of spin is small, the wheel will tilt about Y'Y
appreciably, and on the finger being removed the whole system
will oscillate violently. If, however, the rate of spin is large,
only a very small tilting, if any, will be appreciable, while on
the removal of the finger the violent oscillations observed
previously are now hardly more than a " shiver" of the axle.

*The gyroscope here depicted is known as Wheatstone's Compound, and can
be procured of Newton & Co., at the cost of 3 guineas.