Mr Alger on New Localities of Bare 3Ii?ierals. 



These results agree with those obtained by Hoftmann,*in his analysis 

 of the same mineral, the specimens of which were presented to him by 

 Charles Cramer, Esq., of St Petersburg. 



Washingtonite of Shepard, analysed by Mr J. S. Kendall, under 

 the direction of Dr Jackson, gave these results : — 



Oxygen. Ratio. 



Titanic acid 25-28 4-82 1 



Peroxide of iron, 51*84 10.36 2 



Protoxide of iron, 22-86 5-08 1 



99-98 



The atomic proportions are thus nearly one atom titanic acid, two 

 atoms peroxide of iron, one atom protoxide of iron ; or a tritianiate 

 of iron, consisting of two atoms tritianiated peroxide, and one atom 

 trititaniated protoxide. If we unite the magnesia and lime with pro- 

 toxide of iron, in the following analysis of an Ilmenite from Arendal,f 

 by Mosander, we obtain precisely the same result. 'The crystalline 

 form of the two varieties is also the same, and thei*e can bo no doubt 

 of then- identity as one species. J 



Titanic acid, 24*19 



Peroxide of iron, 53-01 



Protoxide of iron, 19-91 1 ^a.qq 



Magnesia and lime, 1-01 j '^ 



By referring to the analyses of Ilmenite from other localities, it 

 will be seen that the essential constituents, titanic acid and the two 



* American Journal of Science, vol. xxx., p, 366. 



t The Hystatite of Breithaupt. 



X An acute rhombohedron, P on P 86' 10', for the Ilmenite. Shepard, em- 

 ploying varnished planes of the Washingtonite, makes P on P 86°. Professor 

 Shepard founds the distinction on other than crystallographical characters ; for, 

 he says, it is not thus " shewn to he distinct, in any essential manner, from the 

 axotomous iron-ore of Mohs, or from Crichtonite (including Ilmenite) ; indeed, 

 it appears most probable, that all these minerals are not only identical in their 

 angles, but are ismorphous with sj)ecular iron." — American Journal, vol. xliii., 

 p. 365. The analysis, now, would seem to destroy the groundwork for any dis- 

 tinction. 



