644 Professor Andrew Gray [Feb. 14, 



which represents a tight-rope balancer. The structure terminates in 

 wheels adapted to engage on the wire. Attached to the gyrostat are 

 two arms, and carried by these is a light rod weighted at both ends. 

 My assistant spins the flywheel and places the structure upon the 

 wire with the legs vertical and the pole horizontal. . The top, as you 

 observe, balances on the wire. If the top tilts over on the wire 

 towards me, the gyrostat processes in the direction which carries the 

 pole over towards you, and vice versa. That is, if the balancer begins 

 to fall over to one side it immediately puts over the pole to the other 

 side. The action is exactly that of a tight-rope acrobat. 



The rider of a bicycle keeps the machine upright by operating 

 the handle-bar. If the machine tilts over to the left the rider turns 

 the handle-bar to the left, and the forward momentum of the bicycle 

 and rider, aided by the gyrostatic action of the wheels (a relatively 

 small factor in this case) results in the erection of the machine. 

 Similarly, if the machine tilts to the right the front handle-bar of the 

 machine is turned to the right. 



Here I have a small bicycle of the old-fashioned " high " type, 

 provided with a gyrostatic rider. When the gyrostat is spinning 

 rapidly you observe that the top is completely stable. The gyrostat 

 ■operates the front wheel, just as does the rider on the ordinary 

 Incycle. 



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 consequence 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 oflf, and the rate of walking 

 increases, until finally the gyrostat literally runs along the wires, 



