CAPACITY FOR HEAT OF MFTAI.S AT DIFFERENT TEMPEKATI'IM > 



171 



The data supplied by the manufacturers indicate that the physical condition of the 

 iron is probably distinct from that of the other metals, and this may to some extent 

 account for the marked difference in the rate of change of its S and curve over the 

 range 0" C. to 100 C., as compared with the remaining curves. 



We are desirous of maintaining the iron in its present condition until we have 

 invest i<,';if<l its l*'li;i\ imir ut low temperatures, but we hope eventually to ascertain 

 the effect of careful annealing on this specimen. 



TABLE XX. -"Copper. 

 Weight, 3392 grms. Density, 8"922. 



S, = 0-09088 (H-0'0005341^ - 0'00000048(! ! '). 



This copper was electrolytically deposited. 

 Mr. C. T. HEYCOOK writes as follows : 



" Cu = 99*95 per cent. Remaining 0"05 per cent, consists of Pb, Fe, and a very 

 little SiOj. You will 1x3 correct in stating that it is of high purity." 



TABLE XXI. Aluminium. 

 Weight, 954 grms. Density, 2704. 



S, = 0-20957 (l + 0-0009161*-0'00000m 3 ). 

 Messrs. Johnson and Matthey state : 



" Aluminium we have reason to believe to be exceptionally pure, say 99'90 per 

 cent., with traces of iron." 



With the exception of one group of three at C., these experiments were extremely 

 satisfactory, so much so that the fifth figure appears to have some real significance. 

 The perfect agreement of the experimental and the curve values is very noticeable. 



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