132 OUTLINES OF NATURAL PHILOSOPHY. 



207. If a cone of which the altitude is a, and 

 the radius of the baser, be suspended from the 

 vertex, the distance of the centre of oscillation 



f ^ 4 a r 2 



trom the vertex is - 4- - 

 5 5a 



WOLFII Elementa Math. torn. n. 459, 460. 



208. If a sphere, of which the radius is r, be 

 suspended by a fine thread, so that the distance of 

 its centre from the point of suspension is a, the 

 distance of the centre of oscillation from the same 



2r 2 



point is a 4- - . 

 5a 



HUGENII Horol. OsciL Prop. 22. 



209. If in the axis of a pendulum, different 

 points of suspension be taken, the distances of the 

 centres of oscillation from the centre of gravity, 

 will be reciprocally as the distances of the points 

 of suspension from the same. 



This proposition holds of solids as well as of plane 

 figures. 



210. The centre of oscillation of a compound 

 pendulum, may be found by comparing its vi- 

 brations with those of a simple pendulum of a 

 known length, the lengths of two pendulums 



being 



