101;-]] on Gyrostats and Gyrostatic Action 645 



with considerable loss of dignity. When the gyrostat is enclosed 

 in a box, or within an acrobatic figure, the behaviour 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 Fig. 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 centre 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. Each 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 system is left to itself, 

 when it turns round in azimuth. One of the small gyrostats 

 throw's itself up and balances on the bar. The experiment is re- 

 peated 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. 



This top admits of a large variety of designs. It is easy to 

 imagine a gyrostatic circus rider performing balancing feats on the 

 back of a gyrostatic horse ! 



I conclude with a gyrostatic model (Fig. 19) which depends for its 

 action upon an entirely novel and practical method of operating a 

 gyrostat or gyrostats. The method has a very large variety of applica- 

 tions, into which I shall not enter at present. It is here shown applied 

 to a motor-car. The car runs on two wheels in tandem ; it can be 

 set to run either in a straight path or a path curved in either direc- 

 tion. The arrangement includes two parts connected by a vertical or 

 nearly vertical hinge. Each is supported on a single wheel. The 

 front part carries a gyrostat with axis horizontal (in this case), 

 the afterpart contains the propelling mechanism. A quasi- gravita- 

 tional field of force is produced by the propeller behind acting 

 through the hinge, and the construction is such that there is 

 true stability, not the quasi- stability, accompanied by continually 

 increasing gyrostatic oscillation, which obtains in many other cases. 



[A. G.] 



