GYROSTATS AND GYROSTATIC ACTION—GRAY. 207 
Again, here is a small safety bicycle provided with a gyrostatic 
rider. (Fig. 16.) In this case the gyrostat is mounted above the 
back wheel, and is connected by arms to the handle bar of the front 
wheel. The action is the same as in the other model. 
The tops I have shown you are very interesting from the fact 
that in each case the gyrostat not only detects but sets about correct- 
Ing any tendency of the top to fall over. They behave as if they 
possessed both a nervous and a muscular system. 
I have also here a gyrostat which can be made to progress in 
space by a reciprocating motion—in fact, a walking gyrostat. (Fig. 
17.) The gyrostat is suspended by two chains from two horizontally 
stretched wires. The wires are carried by a wooden frame, which is 
mounted, as you see, on two trunnions carried by wooden uprights. 
The chains attached to the arms of the gyrostat terminate in two 
rings, and these are threaded on the stretched wires. 
The gyrostat is spun and replaced on the wires. When the frame 
is tilted to and fro on the trunnions, the gyrostat walks ‘ hand-over- 
hand” along the wires. By the tilting of the frame the weight of the 
gyrostat is thrown alternately on each of the chains, and in conse- 
quence of the precessional motion the gyrostat moves along, carrying 
the chains with it. 
At present the spin is great, and therefore the precessional motion 
is small. The gyrostat proceeds with a slow and stately motion. 
As time goes on the spin falls off, and the rate of walking increases, 
until finally the gyrostat literally runs along the wires, with con- 
siderable loss of dignity. When the gyrostat is inclosed in a box, 
or within an acrobatic figure, the behavior seems very mysterious. 
Here is still another form of acrobatic top, consisting of a large 
gyrostat, the axis of which is horizontal, and two small ones, with 
axes vertical, mounted, one on each side of the large one, on sleeves 
threaded on a horizontal bar, as shown in figure 18. My assistant 
spins the flywheel of the large gyrostat, which is then suspended by 
means of a string and hook from the upper bar of the frame. At 
present the center of gravity of the gyrostat is vertically below the 
hook, and under these conditions there is no precessional motion. 
He now spins the two small gyrostats and attaches them to the large 
one. Hach small gyrostat is carried by two sleeves which are threaded 
on a horizontal bar. The hook is now transferred to one of the side 
recesses provided in the upper bar of the large gyrostat, and the sys- 
tem is left to itself, when it turns round in azimuth. One of the small 
gyrostats throws itself up and balances on the bar. The experiment 
is repeated with the hook engaging in the other side recess, when you 
observe that the small gyrostat which previously occupied the lower 
position now rises into the upright one, and the gyrostat which 
occupied the upright position now occupies the lower one. 
