110 METEORIC IRON. 



rarely amounts to 1 per cent., and the insoluble residue 

 usually amounts to 3 per cent. 



In order to detect the nickel, the hydrochloric solu- 

 tion is first saturated with sulphuretted hydrogen in 

 order to precipitate traces of copper and tin, which 

 occasionally occur; the protochloride of iron is then 

 converted into sesquichloride by heating the solution 

 nearly to boiling, and adding small quantities of chlo- 

 rate of potassa. The solution is then mixed with an 

 excess of ammonia, when all the sesquioxide of iron 

 is precipitated, whilst most of the nickel remains dis- 

 solved. When the amount of nickel is rather large, 

 the filtered liquor is more or less blue. Sulphide of 

 ammonium precipitates from it black sulphide of nickel. 



Or the solution is neutralized with carbonate of soda, 

 acetate of soda added and boiled, when the iron with 

 only a trace of nickel is precipitated, the nickel and 

 cobalt remain in solution. 



In order to detect the phosphoric acid contained in 

 the sesquioxide of iron, it is dried and ignited with an 

 equal weight of carbonate of potassa and soda, and 

 the alkaline phosphates extracted with water. The 

 solution is then supersaturated with acid and the phos- 

 phoric acid precipitated by ammonia and sulphate of 

 magnesia. 



In order to obtain the amount of phosphorus con- 

 tained in the black residue left on dissolving meteoric 

 iron in hydrochloric acid, it is finely powdered, mixed 

 with about half its weight of nitrate of potassa and 

 then with an equal weight of carbonate of soda, and 

 ignited; the mass is then extracted with water and 

 treated as above. The oxidized residue is dissolved 

 in hydrochloric acid and the nickel detected as above. 



In quantitative analyses the iron is separated from 

 the nickel and cobalt, either by succinate of ammonia, 

 or by carbonate of baryta, see No. 25. The phosphoric 

 acid is contained in both precipitates. Cobalt and 



