Analysis of Warwickite. §7 



separating it was tried, by first throwing down the titanic acid 

 from a dihite sulphuric sokition by ebullition, and then precipita- 

 ting the oxide of iron and yttria by potassa, and subsequently 

 withdrawing the yttrious earth from the iron by carbonate of am- 

 monia ; but this process equally failed — titanic acid being also 

 mingled more or less with the potassic precipitate : and I am 

 obliged to confess that I do not regard the proportion of yttrium in 

 the compound as yet determined with precision, although I con- 

 sider its presence as unessential to the mineral. The iron was 

 separated by succinate of ammonia. To estimate the titanium 

 the increase of weight in the mineral during its oxidation by sul- 

 phuric acid was noted, and found to be 13.2 on 48 parts. The 

 peroxide of iron and di-sulphate of yttria, (this being the suppo- 

 sed state of the iron and yttrium of the mineral after digestion in 

 sulphuric acid and ignition,) were deducted from 61.2, which left 

 54.67 for its titanic acid. But 54.67 of titanic acid contains 32.9 

 of titanium. The iron which corresponds to the quantity of the 

 peroxide obtained equals 3.5 ; and the yttrium answering to the 

 di-sulphate of yttria 0.4. Upon the supposition that the titanium, 

 the iron, and the yttrium are each combined with half an atom 

 of fluorine, we make up the original quantity submitted to analy- 

 sis, with the fractional excess only of 0.99, on 48.00 parts. We 

 have therefore in 100 parts of the mineral. 



Titanium - - - 64.71 

 Iron - - - - 7.14 



Yttrium - - . .80 



Fluorine - - - 27.33 



Aluminium, a trace. 



99.98 

 If we regard yttrium as adventitious, Warwickite is a compound 

 of twelve atoms of di-fluoride of titanium and one of di-fluoride of 

 iron. The formula is 12 Ti Fl + Fe Fl. 



Charleston, (S. C.) January 12, 1839. 



