166 PROCEEDIXGS OF SECnON B. 



dipped both in clean mercury. The clip from the distilled water 

 refused to amalgamate, while that from the spring Avater completely 

 amalgamated in a second. It was, however, remarked at the 

 time, that even the silver from the spring water, tested by the 

 side of a clip tliat had been kept dry, manifested a slight hesita- 

 tion, as it were, to the process. Evidently before amalgamation 

 could take place, some chemical combination had to be overturned 

 by the mercury. 



I found that silver which had been kept in distilled water until 

 it became non-amalgamable, was rendered readily amalgamable 

 by immersing it for a short time in spring-water. The same 

 effect was also produced on the silver by ferrous sulphate, acetic 

 acid, and alkaline chlorides, or by heating it to a temperature 

 of about 500° F. 



These results taken conjointly, signify, I think, that silver is a 

 metal which oxidizes with far greater facility than we have 

 hitherto considered possible. 



Thus in the distilled water the silver appeal's to have oxidized, 

 and afterwards, or simultaneously with this process, combined 

 with carbonic acid to form a carbonate, which I have found by 

 actual experiment, is only decomposed by mercury very slowly 

 indeed, so that the silver coated in this way is practically non- 

 amalgamable. 



That amalgamation in the case of the clip from the spring- 

 water not being quite instantmteous, shows that it had become 

 coated with a film. 



In dry air, silver remains clean, that is amalgamable ; and I 

 could not observe that sunlight exerted any eftect in regard to 

 these reactions. 



The knowledge that silver is easily oxidizable in air and 

 moisture, led me to extend my investigations to gold, the question 

 arising, might not even it be affected by the same agencies ? 



The results of my experiments with gold may be briefly 

 summarised as follows : — 



1. — That gold immersed in spring- water for a few hours, or 

 in water charged with neutral salt, refuses for a long- 

 time to amalgamate with mercury. 

 2. — That it is also passed to this condition by contact for 



about eighteen hovirs with distilled water. 

 3. — That it is also thus affected by being placed in contact, 

 for a short time, with an aqueous solution of caustic 

 or carbonated alkali or ammonia, at their boiling 

 points respectively, or for a somewhat longer time, 

 when the solution used is at a common temperature ; 

 also when ignited with carbonate of soda. 

 4. — That when pvit into this condition, as to its surface, it 

 becomes readily amalgamable by a short contact with 

 either weak acetic or hydrochloric acid ; also by 

 isfnition. 



