MEASUREMENT OF OSCILLATIONS. 



Each partial time ^ - / , / 2 - t l is divided by the value i + (3 Q) 



i+ /?! for the corresponding deflection - - , , and we 



get an approximate value f t( of twenty infinitely small vibra- 

 tions. If the values thus calculated do not systematically differ, the 

 phenomenon is regular and the correction exact. The mean of all 

 these values is finally taken as the time of a vibration. 



The table of observations and of successive reductions is arranged 

 as follows : 



Order of Time of Angle of Duration of Mean Reduced 



Transit. Transit. Deflection. Vibration. Deflection. Time. 



20 /, 



'l-'l 



40 / 2 a 2 



'3-'2 

 60 f, a 3 



t.-t. 



3 d / 4. c 



/4 ~ /3 ~v /a= rr^ 



80 / 4 a 4 



loo / 5 a 5 



We shall have, finally, for the time r of infinitely small vibrations, 



IOO 



The errors made in the intermediate transits do not appreciably 

 affect the value of r, and the accuracy depends specially on the 

 exactitude with which the initial and the final transit has been noted. 



