34 Mr. T. S. Hunt on a new Titaniferous Mineral. 
sesqui-oxide of tin, and isomorphous with the peroxide of iron; 
and the same view is advocated by von Kobell.* This oxide is 
the blue compound which is formed when we digest a solution of 
titanic in hydrochloric acid with metallic copper ; it forms a blue 
solution from which the oxide is precipitated by ammonia or 
carbonate of lime as a bluish black substance, which rapidly ab- 
sorbs oxygen and becomes titanic acid. 
It is however difficult to prove the existence of this oxide in 
titanic iron by actual experiment, as it is found that if we boil 
the blue solution of the sesqui-oxide or rather the sesqui-chlo- 
ride, with per-chloride of iron, the iron becomes reduced to the 
state of proto-chloride, while the titanic oxide is converted into 
titanic acid. A similar reaction may be supposed to take place 
in the solution of the mineral, and hence we obtain as the result, 
titanic acid and protoxide of iron. 
This theory of the composition of titaniferous iron, is the only 
one which satisfactorily explains: its isomorphism with specular 
iron. Mosander ing tion of this fact, 
that a titanate of iron (Ti: i>, Fe O) piisted in these minerals, 
which was isomorphous with ptatirliies of iron, but we‘know of 
no instance of isomorphism between two bodies, one a salt and the 
other a simple oxide. If however we admit the existence of this 
titanic oxide, it can from its PR Sa: Sieanean with any 
proportion of peroxide of iron. : 
I would suggest that the titanium in ‘thie hin, exists in the 
form of titanic oxide, and the following reaction seems to favor 
this view. In an attempted analysis, a portion of the powdered 
mineral was mixed with sulphuric acid in asmall flask, and digested 
for some time at a gentle heat; the mixture formed a solid crust 
on the upper part, but on the under surface next to the glass, a beau- 
tiful ultramarine blue tint appeared, which however disappeared 
on the addition of water. It was I think due to the presence of 
oxide of titanium, and did not the scarcity of the mineral forbid, 
I would make more extended experiments, to determine with cer- 
tainty the nature of this curious reaction. 
Admitting that this is the state of the titanium in this mineral, 
and that the iron consequently is a peroxide, we have for its 
=— | 
+ Annal, de Chim. we Pye ome, No 1845, p. 321. 
