350 



Prof. W. C. Roberts-Austen. 

 FIG. 3. 



\\ 



[Mar. 12, 



PURE GOLD 



GOLD V,,TH 0-47^ ALUMINIUM. 

 GOLD *MTH o-5 or LFAD 



heat of fusion of gold, and this had not been determined, probabl 

 because the accurate measurement of the latent and specific heats 

 metals with high melting points, such as gold, presents many mo 

 difficulties than the determinations of similar constants for bodi 

 having low melting points. 



Violle* found the specific heat of platinum at different tempera- 

 tures by heating a piece of the metal in a specially constructed mufti 

 the temperature being simultaneously determined by means of 

 porcelain air- thermometer. The temperature of the metal being 

 known, he plunged it into a calorimeter, and calculated from the data 

 he obtained the mean specific heat of platinum between the extreme 

 temperatures of the experiment. By making many experiments at 

 different temperatures, he was able to deduce the specific heat of 

 platinum at any point within the range, and he found that it regularly 

 increased with the temperature. The data, thus afforded, enabled 

 him to obtain the freezing point of platinum by transferring metal 

 just after solidification into the calorimeter. Further, by pouring 

 metal just before its solidification into water, it was easy to determine 

 the total amount of heat evolved during cooling. Hence, knowing 



* ' Comptes Benclus,' vol. 85, 1877, pp. 543540. 



