500 Stress and Strain on the Properties of Matter. 



Table IV. 



Metal.* 



Density. 



Thermal 

 capacity per 

 unit volume 

 between 

 0° C. and 

 100° C. 



c„t. 



" Young's 

 modulus." 



e. 



e 



°.* 



Cadmium . 



o boo 





575 x llr 



3017 x 10° 





2-942 



•5207 



614 -4 



2819 



Gold 



18 275 



•5920 



685 -5 



2330 





8 -471 



•7958 



1005 



1714 



Palladium. 



11-288 



•6694 



1077 



2747 



Piano-steel. 



7-727 



•8748 



2049 



2801 



Nickel .... 



8-705 



'9559 



2480 



2755 









Mean .... 



2597 x 10 6 



Of the seven substances entered in Table IV, we find five for which 

 the values of — 7 lie closely to the mean value 2597 X 10 6 , whilst 



brass, an alloy be it remembered of copper and zinc, furnishes an 

 exceptionally low value. The mean value here agrees fairly with the 

 mean value recorded in Table III, namely, 2561 X 10 6 . But even in 

 some of those cases where the departure from the mean value is great, 

 more recent investigations of my own on " Young's Modulus " and on 

 torsional rigidity, in which very great precautions have been taken to 

 avoid the effects of imperfect elasticity, have resulted in giving values 



of e which would make the products of e and — , lie closer to the 



mean values here obtained. This is so for the metals copper, zinc, 

 and brass, but not for platinum, which is still remarkable for having 



the value of — r much higher than the mean. It may be remarked 



that the ratio of lateral contraction to longitudinal extension was, 

 according to my previous determinations, much less with platinum 

 than with any of the other metals. J 



* The numbers in columns 1 and 4 are, with an exception in the case of nickel, 

 taken from Sir W. Thomson's article on Electricity, " Encyc. Brit." For the elas- 

 ticities of nickel see " Phil. Trans.," Part I, 1883, p. 126. 



f As there are no data for determining the thermal capacity at 20° C, that 

 between 0° C. and 100° C. is here given : therefore C v is here slightly higher than it 

 should be if we are to compare the results given in the two table?. 



X Loc. cit., p. 28. 



