148 Proceedings of the Royal Society of Victoria. 



Experiments were also tried on strips cut fronn the same alloys 

 with the same solvent, only in this case the strips were placed 

 in large test tubes and not disturbed. The action, as might be 

 expected, was slower. 



Next, the same series of alloys were used to test the solubility 

 of gold in chlorine solutions. 



A number of tubes were connected and partly tilled with 

 chlorine water — strips were placed in each tube and a slow 

 stream of chlorine allowed to pass through them in a dark 

 chamber for 90 hours. The strips were then washed with 

 water, then with ammonia water until the chloride of silver 

 which had encrusted the surface had dissolved ; these were 

 then dried and weighed. 



A solution containing -1 per cent, of chlorine was allowed to 

 remain in contact with another series of strips for SO-t hours, 

 but the action was exceedingly slow. 



It will be seen from the results of these experiments, that an 

 alloy containing 95 per cent, of gold is dissolved more readily 

 than pure gold or than alloys having a greater percentage of 

 silver. 



Further, that tliese alloys are not dissolved regularly and 

 evenly, but that in some cases the action of the solvent is 

 slower at first and more rapid after some time : since a 

 crystalline surface was developed on those placed in the cyanide 

 solution this may be due to rather a definite compound being 

 more rapidly dissolved or the material between the crystals 

 being attacked and thus allowing the crystals to stand out in 

 relief. 



It will also be seen that those alloys approaching the formula 

 Au. Ag. are more evenly dissolved than those diftering widely 

 from that formula, the latter having a higher ratio of silver after 

 partial solution, while the former are practically unchanged. 



The circulating solution dissolved more gold in the same time 

 than the fixed solutions. 



In the case of the saturated chlorine solution the action was 

 exceedingly rapid as compared with the cyanide, but even after 

 90 hours' contact only from 50 to 85 per cent, of the strips 

 was dissolved. 



