a 
CHARLES B. WARRING. 149 
or off to the floor, but still it maintains its upright 
position. 
You notice that it not only runs about in a spiral, but 
that it swings, or gyrates, around a vertical axis. If the 
point, instead of being somewhat blunt, is very fine and 
sharp, and well centred, the top will scarcely travel at 
all, but will swing around an almost stationary vertical 
axis. If the point—very fine and sharp, and well cen- 
tered, remember—happens to fall into a slight pit in the 
surface of the table, it will cease to travel, but will con- 
tinue for a very considerable time to gyrate around a 
vertical, and will be remarkably stable, no matter at what 
angle it leans. Hence, it follows that it is not the trav- 
elling of the top which keeps it up. You 
may stop that entirely with no sensible 
effect upon its staying up, but the in- 
stant—even in the case of one that leans 
ever so little—I prevent the rotation 
around a vertical, it falls. 1 vary the «"y" > 
experiment in every possible way, the result is the same ; 
the moment the swinging—or, gyration, as it is called— 
around a vertical ceases, the top falls. 
Certainly, in case of the bicycle, there is no swinging 
—-gyrating—around a vertical axis. Whatever else the 
machine may do, it does not do that. 
We may, I think, dismiss the top from further consid- 
eration ; but there is another instrument apparently 
much closer in its relationship to the bicycle. I have 
here a gyroscope with its wheel upright like that of a 
bicycle. (See Figs. 3 and 4.) The lower part of the ring 
rests in a kind of trough, to the bottom of which is at- 
tached crosswise a piece of metal (best seen in Fig. 8) 
curved on the lower edge, and with two projecting wires 
by which it may be drawn back and forth in the plane of 
the wheel. 
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