629 



W(' \\\\\ discuss jlio iiidicalioiis rcl'ci'rcil jo ;il)0\'0 iii oiir delaiJed 

 paper in tlic ZtMtsclifit'l tïir plivsikalisclio (lluMnio; 1km(> only two 

 points may bc sj)ecially ineulioiiod -. 1. Matthiksskn and von P)Osk ') 

 found as eai-ly as tifty years ago, thai wires of cleelroly tie co|)pei' had 

 elianged their electric condncti\'ity (at 0° C'.) after having been lieated 

 for some time at 100° (J. Table J illustrates this phenomenon. 



2. Even in those cases where pui-e copper was nsed, the values 

 gi\en in the literature for the density of this metal differ amongst 

 themselves very considerably. ') 



2. We carried out our experiments in the same way as those 

 described in our paper "On the Ailotropy of Zinc". ^) 



Electrolytic coppei- (Kahlbaum — Berlin, "geraspelt") was brought 

 in quantities of 100 grams each into a porcelain crucible. The pure 

 metal was melted in an electiic furnace, some charcoal j)Owder 

 having been added to it. The luelled material which showed a 

 brilliant surface was poured out into cylinders made of asbestos-paper. 

 As soon as the metal had solidified, the cylinders were chilled in 

 water and turned into thin shapings on a lathe. 



55 grams of this material after having been washed with ether, 

 dilute nitric acid, water, alcohol, ether, and dried in vacuo over 

 sulphuric acid, were put into a pycnometer in order to determine 

 the density at 25° C. We then observed that the water meniscus in 



') Poggendorff's Ann. 115, 353 (1SG2). 



^) Co:)ipue (_■ g. KviiLB.vuM II. Stui^m, Zeitsclii'. f. anorg. Ciiemie 46,280(1905). 



") Proceedings 16, 5G5 (1918). 



