5^6 Intelligence and 'MisMlaneom Articles. 



and afterwards the lime by caustic potash. M. Rose observes, that' 

 these three analyses, which have been made for a considerable time,' 

 are not entitled to great confidence ; he afterwards states, that Fuchs 

 has recently given an analysis of the sphene of Schwartzenstein in 

 Zillerthal, by a very ingenious method. The action upon it by hy- 

 drochloric acid not succeeding, he fused it with potash, and boiled 

 the calcined mass in distilled water, in order to get rid of the excess 

 of potash, and separated by the usual processes a small quantity of 

 silica dissolved in the operation. The residue was dissolved in con- 

 centrated hydrochloric acid, and the solution out of the contact of 

 air was left for several days in contact with copper turnings at a 

 moderate temperature. The silica formed a jelly, whilst the titanic 

 acid, reduced by the copper to the state of oxide of titanium, re- 

 mained dissolved in the liquor, which became of a deep blue colour. 

 The silica being separated, the oxide of titanium contained in the 

 liquor was converted into titanic acid, and precipitated by ammonia U 

 an oxalate poured into the filtered solution precipitated the lime.; 

 The quantity of copper dissolved by the hydrochloric aeidgaVe that- 

 of the titanic acid. . > >!)n:jH 



.jfWhe results were, — ij^iJadj .c.J{iOiiai| .-u^ !■ 



Y<f ^' Titanic acid %A^.hA^'yyr- 4^2t T 



anil yi'diBvbboy Silica 32-52 



b9jfi3ii ba« . Limp,..!.. 24" 18 



I bdbbjs sd oi si fafisi to slBJsaa ^b^y qq.^in; pdcf ^ laiBw sbvtT 



M. Rose states, that the best method of analysing sphene, when 

 the determination of its three elements directly is desired, consists 

 in the use of concentrated sulphuric acid. The mineral, reduced to 

 an impalpable powder, is put into a platina crucible with sulphuric 

 acid diluted with half its weight of water ; the mass is to be heated 

 and stirred till the sulphuric acid begins to volatilize. The titanic 

 acid dissolves in the sulphuric acid, the lime and silica separate ; 

 when the mass is cold, it is to be treated with a large quantity of 

 water; the silica which remains is not however pure, but is of a 

 yellowish colour, and it requires to be five times treated with sul- 

 phuric acid to be rendered pure and colourless. When the solution 

 is treated with carbonate of soda it gives an insoluble residue, cer- 

 tainly more considerable in quantity than any of those yielded by 

 the same treatment with other silicates, but much smaller than the 

 residue left by the silica of sphene acted upon by hydrochloric acid. 



r022 gramme of the sphene of Zillerthal gave 0-;538 of silica, 

 neglecting, after its treatment with carbonate of potash, a residue 

 of 0'052. This residue was completely acted upon by fusion with 

 bisulphate of potash ; the fused mass, treated with water, left 0044 

 of insoluble silica. The filtered liquor contained no titanic acid ; 

 but by the usual process 0"008 of lime was separated from it. After 

 the separation of the silica, the titanic acid was precipitated by am- 

 monia ; it weighed 0'436 gramme, and contained 0-011 oxide of 

 iron, which was separated from the solution of the titanic acid in 

 ^^^^oncentrated sulphuric acid ; the lime obtained after the sepa- 



