Metals in Persulphate and Perchloride of Iron. 369 



of persulphate of iron ; but in perchloride of iron 2 equivalents 

 of cadmium are dissolved for every equivalent of perchloride 

 of iron, forming, as in the case of copper, a subchloride, which 

 was not precipitated by the addition of water. 



Lead is also dissolved in persalts of iron, reducing a portion 

 of the iron to the state of a proto salt ; the lead becomes co- 

 vered with a thin crust of sulphate or chloride, which seems 

 to protect it from further action; when the iron solution is 

 boiled with the lead much more is dissolved, and a precipitate 

 of peroxide of iron collects at the bottom. This action of iron 

 on lead may account for the rapid destruction of leaden tanks, 

 noticed by Mr. West at the last Meeting of the British As- 

 sociation, that when spring water, which had been running 

 into a lead tank for many years without the slightest action 

 upon the lead, was conveyed through iron pipes to the tanks, 

 the tanks were destroyed in six years. 



Antimony is not very soluble in persulphate of iron even 

 when heated, but it is very soluble in perchloride of iron when 

 hot, reducing the iron to a protochloride in a short time, the 

 solution becoming of a light brownish colour. I found that 

 if kept boiling slowly for a long time the antimony loses an 

 equivalent of metal for every equivalent of peroxide of iron, 

 giving us the idea of the existence of a compound of antimony 

 with chlorine of one to one. This solution was not examined 

 further than by dilution with water, which precipitated almost 

 all the antimony as a white powder, undergoing the usual 

 changes of common chloride, except when the dried precipi- 

 tate was boiled in nitric acid, in which it dissolved with the 

 evolution of nitrous gas. 



Arsenic is very soluble in perchloride of iron, reducing the 

 iron to the state of protochloride, losing also with long boil- 

 ing an equivalent of metal for every equivalent of peroxide of 

 iron in the solution ; but this result is not obtained without 

 long boiling. 



Bismuth is very soluble in perchloride of iron, slightly in 

 persulphate ; the perchloride is completely reduced to the 

 state of protochloride, a full equivalent of metal being dis- 

 solved for the peroxide of iron present ; this is wholly preci- 

 pitated by dilution. 



Cobalt is very soluble in perchloride of iron, reducing it 

 completely, changing the solution to a pink colour ; the co- 

 balt salt formed crystallizes from this solution very easily. 



Nickel is also soluble in perchloride of iron, giving a pre- 

 cipitate of brown oxide of iron; the solution becomes green, 

 containing protochloride of iron and nickel ; a portion of the 

 nickel is precipitated as a fine white powder by dilution. 



Phil, Mag. S. 3. Vol. 24. No. 160. May. 1844. 2 B 



