296 



VII. DYNAMICS OF ROTATING BODIES. 



which is found to be the same for the same value of m, as may be 

 verified on the figures. 



In order to illustrate the more general case above treated, the 

 spinning top is included in a system of two pendulums (Fig. 104), 

 whose frequencies may be made to have any ratio to each other, so 

 that when the top is not spinning the point describes a Lissajous's 

 curve. The influence of the spinning on the curves is shown in Fig. 105. 



Fig. 105 a. 



Fig. 105 b. 



An interesting application of the heavy symmetrical top is the 

 gyroscopic horizon invented by Admiral Fleuriais of the French navy. 

 A small top is spun upon a pivot in vacuo, in a box which is 

 attached to a sextant. The top executes a slow movement of precession 



Fig. 105 c. 



Fig. 105 d. 



about the vertical, and by means of lines ruled on two lenses which 

 it carries, the vertical is observed, so that observations may be made 

 when the horizon is obscured by fog. 1 ) 



1) Schwerer. L'horizon gyroscopique dans le vide de M. le Contre-Amiral 

 Flewiais. Annales Hydrographiques. 1896. 



