420 Miscellaneous Intelligence. 



of the fused mass. The Bltered liquid which first passes is a sa- 

 turated solution of sulphate of potassa ; being evaporated to dry- 

 ness in an iron vessel, it may be reconverted into acid sulphate by 

 fusing it with one-hal|',its.>«e%bt of s^lph^ri«Qi ft^id; tbJ§ ^«»Hiii^ 

 then useful as. before, V- .-..-, ..iv A -^ ■'....,>.,; .r.-^. /■ni--^--^- h_. ■.i.uoMjt 



The oxide of cobalt thus obtained contains no nickel ; so little 

 oxide of iron is present, that infusion of galls does not shew its 

 jgresence ; it may contain a little copper, if that metal be present in 

 ^^he ore, but it is easily separated by the known methods. Sometimes 

 §,ulphuretted hydrogen will produce a yellow-brown precipitate in 

 ^he solution of the fused mass ; this, however, contains no arsenic, 

 jbijit. is either sulphuret of antimony or bismuth, ot a prjiJ^tur^ /jrf 

 both. „" 



It has been found advantageous to add to the fused mass sul- 

 phate of iron calcined to redness, and one tenth of nitre ; then the 

 residue is arseniate of iron, and contains no arseniate of cobalt. 

 •There is then no occasion to act upon the residue a second time for 

 jthe cobalt in it, m,; i? 



^,: This process is founded on the circumstances that the sulphate of 

 i^pbalt is not decomposed by a red heat, and that the arseniates of 

 iron and cobalt are insoluble in all neutral liquids. It is quite 

 evident that to obtain a perfect result, the excess of acid in the 

 bisulphate of potassa must be completely driven off by the red heat 

 applied, — Jnn. de Chimie, xliii. 204. 



«i!0 iy< 



^,^;14. Preparation of pure Oxide of Nickel. Liebeg. — The nickel 

 pre, or kupfer nickel, is to be carefully roasted and mixed with half 

 its weight of fluor spar. This is to be put into a leaden vessel, with 

 three or three- an d-a-half parts of oil of vitriol, and moderately 

 heated. So soon as the heat rises above 212°, the mass thickens, 

 ftnd would become attached to the bottom of the vessel ; but this 

 jnust, by careful stirring, be avoided. A large quantity of fluoride 

 of arsenic rises in vapour, to avoid the bad effects of which the 

 operation should be carried on under a chimney with?, i*M?oi\g 

 i^raught - !!,{ ;^^f?io f 



J, So soon as the mass dries, it is to be taken out, broken into 

 ^rge pieces, and lightly calcined with care in a reverberatory fur- 

 nace, to expel the excess of sulphuric acid ; it is then to be dis- 

 solved in hot water, and after the sulphate of lime has been sepa- 

 rated, the oxide of iron is to be precipitated in the well known 

 way. The roasted ore may also be dissolved in sulphuric acid, 

 to which one-third of nitre has been added, and afterwards mixed 

 with the fluor spar, following the same process as before. . The 

 advantage so obtained is, that after calcination^ the irpft^iaifiSD^^/W- 

 pxide, which facilitates its separation. , , ,;. r:,, ...i 

 \ If the nickel is intended for the preparation of an alloy with 

 copper, it is sufficient to evaporate the solution of sulphate of nickel 

 to dryness, to decompose it by heat, and reduce the oxide of metal, 

 containing a little iron, by the usual means. The small quantity of 



