130 OUTLINES OF NATURAL PHILOSOPHY, 





'42' 2.2.4.4 4 ' 2.2.4.4.6.6" 



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SIMPSON, ibid.; FRANCOEUR, 196. 3*ne e dit. 



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Centre of Oscillation. 



204. When a pendulum consists of two or more 

 bodies, or of one body, from the figure and extent 

 of which we are not permitted to abstract, it is 

 called a Compound Pendulum. The axis of this 

 pendulum is a Hire which passes through the point 

 of suspension, and is vertical when the pendu- 

 lum is at rest ; and its centre of oscillation is a point 

 in this axis, or in the axis produced, in which, if a 

 weight were placed, it would form a simple pen- 

 dulum, vibrating with the same angular velocity 

 as the compound. It vibrates, therefore, in the 

 same time ; or is isochronous with the compound 

 pendulum itself. 



205. The distance of the centre of oscillation of 

 a compound pendulum, from its centre of suspen- 

 sion, is equal to the sum of the products of each 

 body into the square of its distance from the centre 



of 



