12 



A. TANAKADATE. 



2- 



tix 



sin '2tc]z 



— n 



cos •2;r/r + (1 — n)lib 



wlieru ?i is the estimated fraction of a «ecoiul and " tlie [)L'riod of 

 vibration of the magnet. Tal)le I is constructed for the purpose. 



TABLE I. 



Ourrections to be Applied to the Estimated Fractions of 



Hecond when Sirajjle Harmonic Motion is Observed by 



Eve and Ear Method. 



The magnet is suspended with two loops of silk tibre as in 

 Fig. 2 and is free from any mechanical stress except the pressure 

 due to its own weight. The looj^s weigh about h milligram and 



