1883.] 103 [Davis. 
hold in solution two and a half times its volume of chlorine, and that five 
cubic feet of the gas will weigh one pound, and it has been found in prac- 
tice that under the Mears’ system or method, by pressure, the resultant 
solution carried such volume of gas as to require an excessive amount of 
sulphate of iron, or sulphuretted hydrogen (where these precipitants are 
used) to neutralize the excess of chlorine, before they could act in pre- 
cipitation of the gold, Thus adding a cost that our low grade ores will 
not bear; other difficulties and shortcomings, attend the precipitations by 
these reagents, not necessary to describe, as they are well known to all 
who have adventured on any of the various modes of chlorination, and 
which are clearly set forth in Crook and Roéhrig’s ‘‘ Metallurgy,” in de- 
scribing Plattner’s Chlorinating works at Richenstein, upper Silesia. 
From the unsatisfactory results of thus precipitating the gold after it is 
obtained in solution, chlorination processes have been of limited applica- 
tion, being mainly confined to operations on a small scale and to the con- 
centrated tailings of other processes. 
In the effort to overcome these obstacles to success, and to adapt chlori- 
nation to the requirements of enlarged operations, the writer reached re- 
sults which are herein described and explained. 
In an aqueous terchloride, or normal solution of chloride of gold, very 
many substances, both inorganic and organic, will decompose the salt and 
precipitate the gold in a metallic state, or in combination with the sub- 
stances employed ; but excepting the proto-sulphate of iron, or sulphu- 
retted hydrogen, they are quite inapplicable in a solution surcharged with 
chlorine, especially is this the case, in the use of organic substances, 
owing in a measure to their rapid decomposition and disintegration by 
chlorine. 
In vegetable charcoal we find an organic structure capable of resisting 
the destructive influences of chlorine, therefore, after numerous failures 
with other organic substances, this was adopted as subject of experiment ; 
and it was found possessed of a remarkable power in decomposing the 
auric solution, converting the chlorine rapidly into CIE, depositing the 
gold upon, and throughout the charcoal, and*allowing contained copper 
to pass off in the escaping fluid. Thus, by a simple regulated flow through 
charcoal, surmounting the sole difficulty to the employment of the chlor- 
ine process, on an extended scale of operations. 
The gold was retained in metallic form, and of great purity ; by long 
continued action the gold was observed to replace the wasting carbon, 
atom for atom, fibre for fibre, retaining the form and structure of the frag- 
ment of coal, so that on the dissipation of the carbon by incineration, and 
washing away the ash by $03, a brilliant and perfect golden pseudomorph 
of the coal was obtained. 
The copper in the solution was not affected by the coal, and it passed to 
its appropiate tank to be precipitated by iron as cement copper. 
In a report made by Prof. F. M. Endlich, to parties in New York, he 
Says, ‘In order to test the efficacy of the process, I took, systematically, 
