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

70

PRACTICAL APPLICATIONS

motion of the frame of the fly-wheel. The swings of the flywheel frame are thus reduced in extent, and the phase difference
between the two swinging movements here described now
becomes less than 90~.
"If the experiment be made of setting the pendulum swinging
with the brake thus applied to the fly-wheel frame, a very
different phenomenon will be observed. The pendulum will
indeed still swing with a very considerable period, but the
maximum angle attained becomes considerably reduced with
each successive swing, so that a state of rest is reached even
after about two complete swings. In scientific language, the
oscillations of the pendulum experience a damping, in that the
energy stored up in it is converted into heat by the friction
applied to the fly-wheel frame."
The complete paper from which the above is an extract can be
procured at 5 Adelphi Terrace, London, W.C.
71. The first gyroscopic apparatus for steadying ships which
was constructed in England, was made at Newcastle, at the
Neptune Works of Swan, Hunter and Wigham Richardson, and
was fitted in October, 1908, to the R.M.S. "Lochiel," owned by
Messrs. David MacBrayne of Glasgow. It can be thrown in and
out of action at will. When it is out of action, the vessel has
been observed to roll, out and out, through an arc of 32 degrees,
which was reduced to a (total) angle of from 2 to 4 degrees by
the action of the gyroscope. The machinery, which occupies
very little space in the steamer, is driven electrically and requires
very little attention.
III. BRENNAN'S MONORAIL.
W. 1).
MODEL EXHIBITED BEFORE THE ROYAL SOCIETY, MAY 8, 1907.
72. The gyroscope has recently been employed by Mr.
Louis Brennan with striking ingenuity and success to ensure
the stability of a heavy car travelling on a single line of rail
with its centre of gravity above the level of the rail, as is
seen in the accompanying illustrations.
The following pages will serve to illustrate the development
and growth of his idea from the first elementary principles;
but it should be remembered that the application of the gyroscope to methods of locomotion is still in its infancy, and