On Columbite. 149 
Art. XIV.—On the Identity of the Torrelite of THomson with 
Columbite ; by James D. Dana, A. M., Assist. in the department 
of Chem. Min. and Geol. of Yale College. 
Read before the Yale Nat. Hist. Soc. Feb. 21, 1837. 
In a late number of the Records of General Science, (Dec. 1836, 
Iv. p. 407,) Dr. Thomas Thomson has proposed a separation of the 
Columbite of Middletown, in this state, (Connecticut,) from the spe- 
cies heretofore designated by that name, and has denominated the 
supposed new species Torrelite, in honor of our distinguished coun- 
tryman, Dr. Torrey. He has been led to this result, by the dissimi- 
larity which he appears to have obtained, between the specific gravity, 
hardness, and composition of a specimen from the above locality, and 
the same qualities of the Haddam and Bohemian specimens. From 
an imperfect, and evidently very irregular crystal, he has also dedu- 
ced a primary form, distinct from that of Columbite. The author of 
these remarks, having had the pleasure of examining several of the 
splendid crystals, remarkable for their regularity and brilliancy, af- 
forded by the Middletown locality, would here state what appear to 
be the obvious deductions from these crystals, respecting the propri- 
ety of the above distinction. It should be premised, however, that 
although the conclusion deduced may differ from Dr. Thomson’s, 
yet considering the apparent rhomboidal form of the only crystal in 
his possession, and also the other discrepancies which he observed, 
we must regard his conclusions as a fair deduction from the facts ob- 
served. 
The identity of the Haddam and European specimens was clearly 
exhibited by Dr. J. Torrey, by means of figures and descriptions, 
in the Annals of the New York Lyceum, Vol. I. page 89. The 
first of the following figures is copied from this article. To facilitate 
comparison, a representation by Mr. Brooke, of a crystal in his pos- 
session, (Fig. 2,) supposed from Bodenmais, in Bavaria, is added. 
The general forms of these figures are modified rectangular prisms. 
Mr. Brooke obtained the following angles : 
P : 0’ =136° 30’ M 3 €=156° 30’ 
P Se 120° M : €=114° 30’ 
With the reflective goniometer, Dr. Torrey found 
M:éand M: é=1579 M:e=129°50 M: z= 102° 50! 
The angles M : € approximate sufficiently to prove an identity. 
