24 



WILLIAM H. EMMONS 



7. W. J. McCaughey 1 dissolved gold at from 38 to 43 C, 

 in hydrochloric acid solutions of ferric sulphate. The results 

 are indicated by the curves in Fig. 1 . Solution A contained 1 gm. 

 of iron, introduced as ferric sulphate, and 25 c.c. of HC1 (sp. gr. 

 1. 1 78) in a solution diluted to 125 c.c. containing 250 mg. of gold 

 rolled to 0.009 inch. Solution B contained the same amount of 

 iron sulphate and 50 c.c. of HC1. Solution C contained 2 gm. of 

 Fe as ferric sulphate and 25 c.c. of HC1. Solution D had twice 



Fig. 1. — Diagram Showing the Rate of Solution of Gold in Concentrated Solutions 

 of Hydrochloric Acid and Ferric Sulphate. (Illustrating Experiment 7, by 

 McCaughey.) 



the concentration of A. The diagram shows the amount of gold 

 dissolved after different periods of treatment. 



8. McCaughey 2 found that gold is dissolved at from 38 to 

 43 C. in a strong solution of cupric chloride and HO. The 

 amounts dissolved are shown by the curves in Fig. 2. Solution 

 A contained 1 gm. of Cu as cupric chloride and 25 c.c. of HC1 

 (sp. gr. 1. 1 78); solution B, 1 gm. of Cu as CuCL, and 50 c.c. of 

 HC1; solution C, 2 gm. of Cu as CuCl 2 and 25 c.c. of HC1; and 

 solution D, 2 gm. of Cu as CuCl 2 and 50 c.c. of HC1; the final 

 solution being in all cases diluted to the volume of 125 c.c. The 



1 Journal of the American Chemical Society, XXXI, No. 12, 1263 (Dec, 1909) 



2 Ibid., 1264. 



