THE TOP AND THE GYROSCOPE. 503 



The very same principle acts on the boys' Tops, and is shown 

 in a really remarkable manner by the professional Japanese 

 top -spinners, who will place several tops upon each other, as 

 shown in the illustration, and make them sway backwards and 

 forwards in the most extraordinary manner, sometimes being 

 all upright, and sometimes leaning almost at right angles to 

 each other. 



A favourite mode of illustrating this power of Centrifugal 

 Force is by the Gyroscope, a figure of which is given on the 

 right hand of the illustration. The interior wheel is made to 

 revolve rapidly, and the effect of the revolution is to enable 

 the instrument to maintain a horizontal position, even when 

 suspended on one side, as shown in the engraving. 



The power of this revolution is quite wonderful, even in a 

 small Gyroscope which can be purchased for a few shillings. 



REVOLUTION OP EAETH. JAPANESE TOPS. GYROSCOPE. 



It almost seems to be alive, and to insist on retaining its 

 position, in spite of all efforts to the contrary. 



This principle is used in the swinging cabin of the Bessemer 

 ship, and is also employed by quoit-players in keeping their 

 missile steady as it flies towards the mark. Even the now 

 fashionable Bicycle is managed on the same principle. 



As is well known to all bicycle riders, it is comparatively 

 easy to maintain the balance when the pace is rapid and the 

 wheels revolving quickly. The difficulty is, to do so when the 

 pace is slow, and the rider is deprived of the centrifugal force 

 which keeps him on his balance almost in spite of himself. It 

 is just the same with a child's hoop, which runs straight and 

 upright when it is driven rapidly, or when, for example, it 

 runs downhill. But, as soon as the centrifugal force is 

 expended, it begins to waver, loses its direction, and soon falls 

 to the ground. 



