1865.] Hunt on British Gold. * 643 



circumstances, preserved and intensified. It will extract gold from 

 Sulphides, and from such other minerals as have hitherto resisted the 

 ordinary process. It will seize upon gold tarnished hy any of the 

 metals named above, and which would pass untouched through 

 common mercury and be lost. It will absolutely prevent " sickening " 

 and "flouring," consequently the yield of gold is augmented, and 

 a large saving in mercury is the result. 



A series of experiments were made to determine the action of the 

 sodium, under such circumstances as presented unusual difficulties, 

 and the results of these trials were as follows : — 



It should be stated that the mercury contained one per cent, of 

 sodium. 



1. When a little of the sodium amalgam was added to ordinary 

 mercury, the affinity of the latter for gold was greatly increased, so 

 that when pieces of gold were dipped into it they were instantly 

 covered with mercury, although when dipped into mercury to which 

 no sodium had been added, amalgamation was very slow, and difficult 

 to obtain. 



2. " Floured ". mercury immediately ran together into a single 

 globule, on the addition of a little sodium amalgam. 



3. When iron pyrites (bisulphuret of iron), magnetic iron pyrites 

 (sulphuret of iron), or copper pyrites (sulphuret of copper and iron), 

 were triturated with sodium amalgam, the pyrites were decomposed, 

 and on the addition of water, a black precipitate of sulphuret of iron 

 was obtained. 



4. Triturated with sodium amalgam — a, Arsenical pyrites was 

 decomposed and arsenic amalgam formed ; 6, Galena (sulphuret of 

 lead) was decomposed, and lead amalgam formed ; c, Blende (sul- 

 phuret of zinc) was decomposed and zinc amalgam formed ; d, Litharge 

 (oxide of lead) and white lead (carbonate of lead) were decomposed 

 and lead amalgam formed. An extensive series of experiments has 

 been made at the mines near Dolgelly, and in every case, a consider- 

 able increase in the quantity of gold has been effected by the use of 

 the sodium amalgam. The only thing which appears to be neces- 

 sary to ensure the usefulness of the sodium amalgam in all cases, 

 is a preliminary experiment to determine the quantity of sodium 

 which should be used with the mercury. When too much sodium is 

 employed it attracts the other metals present — in some cases to the 

 rejection of the gold ; but when judiciously applied it works with 

 wonderful facility.* This discovery promises many advantages to the 

 adventurers in the auriferous mines of Wales, and it will probably 

 lead to the successful working of some of the poor quartz lodes 

 through which the sulphides and arsenides of the baser metals are 

 disseminated, and thus prove a solution of the problem, Can British 

 gold be worked with commercial advantage ? 



* Since the above experiments were tried, Mr. Crookes has introduced a 

 modification into his process, by which the ill effects of adding an excess of 

 sodium are entirely avoided. The improved process has been thoroughly ex- 

 amined and experimented on by Dr. W. Allen Miller and other high authorities, 

 and the results are said to be very striking. 



