156 T. S. Hunt on the Chemistry of Copper. 
whose reducing power may be still further exerted upon the 
cuprous combination thus formed. These facts serve to explain 
the results obtained by E. Braun (Zeitschr. Chem., 1867, p. 568, 
cited in Jahresbericht for 1867), which were not known to me 
at the time of making these experiments. He found that b 
digesting cupric hydrate or cupric carbonate with ferrous sul- 
hate in solution there was obtained a reddish mixture of basi¢ 
erric sulphate with cuprous oxyd, formed apparently in accord- 
ance with the equation. 
2FeO, SO,+2Cu0=Cu,0+Fe,0,, 250,. 
This, when boiled with a further portion of ferrous sulphate, 
chlorid in the cold, but the insolubility of the resulting euprous 
chlo sthe action. If however the ferrous Biota be 
greenish solution thus obtained readily dissolves recipitated me- 
tallie copper, in virtue of the cupric chlorid which it contains, 
and, unless a large excess of chlorid of sodium be present, de- 
sits white crystalline cuprous chlorid by cooling a 
ate of lime, the greenish sblution deposits one-third of its COP 
pale green insoluble cupric hydro-carbonate, while the 
colorless filtrate retains the remaining two-thirds in the form © 
_ euprous chlorid. If a solution of ferrous chlorid with chlorid 
of sodium is digested with a sufficient excess of cupric OXY the | ‘ 
cupric chlorid formed unites with the latter to form an insoluble | 
cupric oxychlorid, and only cuprous chlorid remains in solt- 
* Metall. Huttenkunde, xi, 588, 
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