AND TIIK RELATION OF SPECIFIC HEAT TO ATOMIC WEKU1T. 



241 



The metal was then melted in a porcelain crucible by an oxyhydrogen flame applied 

 outside. 



Gold after fusion. S.G. 19 "227 at 18/18 . 



There is very little difference between the two series, the value after fusion being 

 a little higher. 



REGNAULT'S mean value for the specific heat of pure gold is "03244 by the method 

 of mixture. 



The platinum was prepared from scrap, chiefly foil. After successive treatment 

 with hydrochloric acid, water, nitric acid, and washing, the metal was dissolved in 

 aqua regia, the solution evaporated to dryness, and the residue was heated above 100 

 degrees for some time. The chloride was redissolved in water, the solution filtered, and 

 excess of pure ammonium chloride added. The precipitate was bright orange yellow. 

 It was washed with water, dried, and heated slowly to redness. The spongy metal 

 was then compressed in a steel mould, and the resulting cylinders boiled in dilute 

 hydrochloric acid, and then fused by an oxyhydrogen flame upon a support of pure 

 lime. The buttons obtained were bright and lustrous, but the under surface which 

 cooled less rapidly was blistered from the escape of gas. And from the specific 

 gravity, which in various experiments was found to be 20'23, 20'33, 20'1G, it was 

 obvious that all were more or less permeated by cavities, although when this metal 

 was heated to redness in a Sprengel vacuum it gave off no gas. Turnings obtained 

 from one of these buttons had a specific gravity 21 '323 at 18 C /18. After rolling 

 one of them into a strip, it had a specific gravity 21 '424 at 22/22. 



Series VI. 

 Specific Heat of Platinum after fusion. 



VOL. CXC1V. A. 



2 I 



