water-tank. 
A small but variable proportion of protochlorid of iron gen- 
erally accompanies the chlorid of copper, and may be separated 
from the cuprous solution by asimple reaction which I also 
studied. Three equivalents of cupric oxyd, and two of ferrous 
chlorid, yield by their reaction one equivalent each of cuprous 
and cupric chlorids, and one of sesquioxyd of iron, 
Cu,0,+Fe,Cl, =Cu,Cl+CuCl+Fe,0,. 
The addition to the heated solution, separated from gypsum 
and insoluble matters, of a portion of cupric oxyd therefore suf- 
fices to precipitate the whole of the dissolved iron, and the din- 
oxyd of copper in the presence of air rapidly produces a simi- 
lar result, The addition of milk of lime now throws down, 
only reagent consumed in the process, in addition to the elements 
of the ore, and the oxygen of the air, being the equivalent of lime 
used to precipitate cuprous oxyd. 
It will be seen that for sulphuretted ores containing gold, the 
treatment in the fire-tower, with the aid of a bath of water only, 
affords a simple mode of desulphurization, and leaves the gol 
particles in a state most favorable for amalgamation, while in 
e case of auriferous ores containing copper, a similar result 
may be obtained, and the copper, which is lost in the ordinary 
a of working such ores, recovered by means of the chlorid 
It is claimed by the designers of this series of processes, that 
copper can in this way be produced, at about one-third the cost 
of the ordinary method. The small consumption of fuel, and 
the mechanical facilities afforded for handling great masses © 
material, are such, that the new method will probably be found 
especially advantageous, in the treatment of low grade ores, 1B 
regions where transportation is difficult, and fuel scarce. The 
patentees have a small experimental furnace eighteen feet high, 
at East Boston, but are now erecting at the Harvey Hill 
