from their Ores by the Wet Way. ^ 



I treated the residual ore a second time with a dilute solu-* 

 tion of hyposulphite of soda, and proceeded in the manner 

 just described. I obtained another bead of fine silver, weigh- 

 ing 0*050. Some loss was also again accidentally occasioned 

 in this second determination. 



4. Goldleaf was digested in a solution of hyposulphite of soda, 

 but it did not appear to be in any degree acted upon ; neither 

 did silver leaf appear to be appreciably dissolved by the saraei 

 menstruum, although the surface after some time became tar- 

 nished, the solution being freely exposed to the atmosphere. A 

 piece of copper wire, which had been previously dipped in ni- 

 tric acid and washed, was immersed in the solution of hyposul- 

 phite containing the silver leaf; but there was not the slightest 

 appearance of the deposition of-silver. However, the surface 

 of the copper acquired a dark colour, and by subsequent ex- 

 posure to the atmosphere became beautifully iridescent. 



5. Into a large stoppered bottle I put 1000 grs. of the 

 roasted, finely pounded and sifted ore. I then nearly filled 

 the bottle with distilled water, and passed a stream of chlorine 

 through for an hour, having previously added 50 grs. of chlo- 

 ride of potassium, with a view to form a stable double salt of 

 gold. After shaking the bottle at intervals during the passage 

 of the gas, there was a manifest absorption of the gas, as 

 proved by the rushing in of the air on withdrawing the stopper. 

 The agitation was repeated several times, and with the same 

 effect. I left the whole for about four days, shaking at inter- 

 vals. When the powder had subsided after shaking, I uni- 

 formly observed the disengagement of numerous small bubbles 

 of gas from the ore. On plunging a spill, burning only with 

 a spark, into the neck of the bottle, combustion was evidently 

 increased, the spark burning distinctly brighter. A strong 

 odour of some oxygen compound of chlorine continued to be 

 evolved. I filtered, and obtained a clear and colourless solu- 

 tion, which I reduced considerably by evaporation. During 

 the evaporation, a white scum formed on the surface, and 

 white matter (PbCl) was deposited, which towards the last 

 occasioned succussions. To the solution thus reduced, when 

 cold, 100 grs. of hyposulphite of soda were added; but the de- 

 posited matter did not appear sensibly to dissolve. I treated 

 the residual ore with a solution of 200 grs. of hyposulphite 

 of soda; 1 filtered and washed. I mixed the filtrate with the 

 solution previously mentioned, and carefully washed in the 

 precipitate. I added hydrochloric acid, and digested as usual, 

 stirring continually. Sulphurous acid did not appear to be 

 copiously evolved. The precipitate thus obtained was red- 

 dish-brown and not black. It was washed on a filter, dried, 



B2 



