Melting-points of Aluminium, Silver, Gold, Copper, fyc. 37 



directly comparable with mine. As regards the influence of 

 pressure Sgr. Lussano finds, in the limits of pressures em- 

 ployed, an increase of c with increasing pressure ; but the 

 influence of the temperature is just contrary to that which I 

 have found at low temperatures. It cannot be doubted that 

 at sufficiently low temperatures the specific heat c p increases 

 with decreasing temperature, since in the critical state its 

 value is positive infinity. This point must therefore be 

 reserved for further researches, the more so, as the increase 

 of c p with increasing temperature, at higher temperatures, has 

 been proved long ago in some gases (carbon dioxide &c.) 

 without any doubt. 



Physical Laboratory of the Yaghellonian University, 

 Cracow, November, 1895. 



II. Melting-points of Aluminium, Silver, Gold, Copper, and 

 Platinum. By S. W. Holman, with E. E. Lawrence and 

 L. Barr*. 



THE following melting-points are offered as provisional 

 only, but with the belief that they are more reliable 

 than previous data. The absolute values depend in part upon 

 the assumption of 1072° C. as the melting-point of pure gold, 

 the recent determination of Holborn and Wien at the Eeichs- 

 anstalt. Should that datum, however, be shown to require 

 revision, the validity of the present measurements would not 

 be impaired, but new values of the melting-points could be 

 readily computed from them which would be consistent with 

 the better value for gold. 



Al. 



Apr. 



Au. 



Cu. 



Pt. 



660° 



970° 



. [1072° C.] 



Assumed. 



1095° 



1760° 



The Pure Metals used were of a high degree of fineness, 

 except unfortunately the platinum. 



The gold contained less than 0*01 per cent, total impurities, 

 these being, if any, probably minute traces of silver and pla- 

 tinum. It was obtained as part of a specially prepared lot 

 from the United States Assay Office in New York through 

 the courtesy of Professor H. G. Torrey, upon whose authority 

 the above statement is made. The purity was at least as great 

 as the best "proof" metal used at the United States or London 

 mints. 



* From an advance proof of the Proceedings of the American Academy 

 vol. xxxi. (n. s. xxiii.) p. 218, communicated by Prof. Holman. 



