IW. .\. \lr. V. .1. lilvlli. ami Mr. -I. S. I>unl<.]>. 



In each riirvr tin- abscissae are amplitudes <>f vibration in degrees, 

 an<l the ordinates, which are drawn downwards in each case, arc the 

 numbers of swings that have been completed from the instant at which 

 the amplitude was 80, the largest amplitude of swing used in the 

 observations of periods. The temperatures are marked on each diagram 

 for the several curves. Curves (1) and (2) of diagram (I) represent 



Amplitudes. 



i 







.30 



30 



60 



1 



DlARKAM T. 



GermaJi silver. 

 QP 40 s 



Curve 



i;emp^207C. 

 S; ' 



izLt. vibnzCor. 



.. 



the observations made in German silver at the lower and higher tem- 

 peratures respectively, stated in the diagram. It will be seen that the 

 rate of dying out of the amplitude is distinctly faster at the lower than 

 at the higher temperature. The reverse was found to be very 

 markedly the case in all the other wires examined. 



In mild steel at 1 7 C. the oscillation, as shown by the curves of 

 diagram II, has fallen from 80 to alxmt 55 in 20 periods, while at 

 89*4 C. the amplitude has fallen to 40 in the same time. After 60 

 periods the amplitudes were respectively 25 and 13. The logarith- 

 mic decrement is practically constant during the subsidence at the 

 lower temperature. At the higher temperature the logarithmic decre- 

 ment diminishes in the ratio of about 75 to 60. 



In brass, for which the different vibrators weighing 3*4 Ibs. and 12'7 

 Ibs. respectively were employed, the rate of subsidence was determined 



