Temperature on Modulus of Rigidity of Solid Metals. 407 



the amplitude of oscillation, the temperature, the tension of 

 the wire, heat, treatment, etc. 



Fig. 1. 



1-6 

 1-5 

 1-4 

 1-3 



IE 

 II 

 1-0 

 0-9 

 0-8 

 07 

 0-6 

 05 

 0-4 

 03 

 0-2 

 0-! 



O I 2 3 4 5 6 7 8 S IO II 12 13 14 15 



Amplitude in daqrees 



Logarithmic decrement-amplitude curves under various Tensions. 

 Nickel wire: radius =0-2o mm. \ : logarithmic decrement. 

 Platinum wire : radius =0*24 mm. T : tension. 



1. Copper. Fig. 2. 



The wire was drawn from electrolytic copper and tested 

 in an annealed state. From curve a we see that the 

 rigidity decreases with the rise of temperature according to 

 a parabolic law. Curve b is obtained for a hard-drawn 

 commercial copper wire, and is quite similar to curve a in 

 form ; but the value of rigidity is greater in this than in the 

 former case for all temperatures observed. This striking 































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