Experiments on the Vibratiotis of Pendulums. 281 



It hence appears, that when a pendulum is suspended by a 

 flexible string, a heavier weight and a consequent greater arc of 

 vibration, causes the clock to lose. 



The following are the dimensions of the springs which were 

 experimented with : — 



The pendulum being suspended by the weakest spring, No. 1, 

 the times were noted as before, in which the arcs of vibration 

 were reduced from 2° to 1°, and from 1° to ^°, no maintaining 

 power being applied. 



Arc reduced from 2° to 1° in Ih. 58m. 

 Do. do. 1 57 



Do. 1 to J 2 8 



Do. do. i 2 10 



With the same spring, and a maintaining power of 41b. loz. 

 and 21b. 2oz., the following arcs of vibration and rate of the clock 

 resulted from two consecutive days, the effective length of the 

 spring being -92 inches. 



Weight. Arc. Rate. 



41b. loz. 2^ 3' - 9s. -6 



2 2 1 30 -6 1 



The pendulum being suspended with spring No. 2, and clipped 

 at ^92 inch, without maintaining power, the arcs of vibration 

 were reduced as follows : — 



From 2° to 1° in 2h. 

 Do. 2—1—2 

 Do. 1 ^ ^ — 2 

 Do. 1 — ^ _ 2 



Applying 41b. loz. and 21b. 2oz. in succession, as a maintain- 

 ing power, I found as under : — 



Weight. Arc. Rate. 



41b. loz. 2° 9' -Os. -2 



2 2 1 36 +2 ^5 



Vol. xxxvii, No. 2.— July-October, 1839. 36 



