CIIAXGF, OF ELASTIC CONSTANTS OF FErcRO:\rAr;\ETTCR. oO 



wore also (Utoniniu^l ; l)nt 2:;onor;illy uo appreciable change wa'? 

 observed. In sonu' of the magnetic wires, tlic damping of tlie 

 oscillation was found to l)ecome slightly faster as the field was 

 increased. Ihit, the chano;e of the looarithmic decrement was too 

 small to sensibly affect tlie })eriod of oscillation, when referred to 

 the equation 



'=To[ 



T=Tn{l + 



St:- 



where T is the actual period of oscillation, Tq that for no damp- 

 ing and y- the logarithmic decrement. This agrees with the 

 results'-' l)y Ignaz Klemcncie, and 11. Tomlinson for iron. 



The values of rigidity at no field were calculated from the 

 jK'riod of oscillation for the bar only, whose moment of inertia 

 was known from its dimensions. 



In tlie oscilhition method, tlie right order of applying the 

 twist and the field was followed. Since the oscillation was very 

 slow, the valne of the I'igidity thus determined may proj)erly be 

 considered to be tlie statical value. Tlie results of experiments 

 are as follows : — 



* Ignaz Klemencic, Wien. Ber. 78, Nov. 7, 1878, 8. 



II. Tomlinson, Proc. Roy. Soc. ■*», 117; T'hil. Trans. 179, 1, 1888. 



