New Phenomena in Chemistry. 



177 



by electrolysis of a solution of ferrous sulphate, the nega- 

 tive pole being formed of mercury." None of these authors 

 appear to be aware of any method of directly amalgamating 

 iron, yet H. Davy distinctly states, that either potassium 

 or sodium amalgam will effect the union of mercury with 

 iron and platinum. 



Mercury has been employed from time immemorial, 

 in separating the precious metals from their earthy asso- 

 ciates. Originally the pure metal was employed, as indeed, 

 it still is to a considerable extent, held in little rifts or 

 gutters in the trough or sluice where they washed the 

 auriferous sands or pounded ore. This was also the 

 method of amalgamation at the stamp-mills, and it is 

 notorious that much gold passed over the mercury in this 

 process, and escaped. Recently I observed in the gold 

 mining regions of the Rocky mountains, at Central city and 

 Nevada, Colorado, that for the rifts and gutters filled 

 with mercury, they had substituted sheets of copper, super- 

 ficially amalgamated, over which the ore reduced to a thin 

 mud, or muddy water, was washed, its gold parting and 

 adhering to the surface oj:" the amalgamated copper, and 

 doing so more readily than it would to the surface of pure 

 mercury. 



Here we have another instance of that combination-action, 

 which we have already noticed in the potassium and sodium 

 amalgams, as evinced by their power to unite mercury 

 with the metals of the second class. It appears that those 

 metals of the first class which are softest, lightest and most 

 easily oxidized (as potassium, sodium, zinc etc.), have the 

 power to enable the harder, heavier and least oxidizable 

 metals of the same class (as copper, silver and gold), to 

 combine more readily with mercury than they would 

 unassisted; and, further, to enable mercury to combine 

 with the metals of the second class, which though generally 



Trans. vii.~\ 23 



