152 On Columbite. 
decisions arising from crystallographic examinations with well defined 
crystals. I have not, however, found the discrepancy in the specific 
gravity, noticed by Dr. Thomson. A fragment of a crystal weigh- 
ing about 52 grains, afforded by one trial 5.95, and by a second, 
5.948 for its specific gravity, which is a near approach to that of the 
Bodenmais Columbite, which is stated at 6.038. Mr. Hatchett obtain- 
ed, for the American specimen in the British Museum, 5.918. The 
specific gravity was determined by Dr. T. at 4.8038. There is, 
however, as stated by Dr. T. a very evident difference in hardness. 
I have found it to vary from 5 to 5.5. The Haddam and Middle- 
town specimens afford a dark reddish brown, or brownish black 
streak, and very frequently present the blue, reddish or yellowish 
tints of the steel tarnish. 
The composition of the Bodenmais and American Columbite has 
been variously stated by different analysts. ‘The following are the 
results of analyses by Borkowsky, Vogel, Thomson and Wollaston: 
Torrelite, from 
: Bodenmais. Bodenmais. Middletown, Con. Bodenmais. Connecticut. 
Columbicacid, 740 7% 73.90 79.65 80 
Protoxydof iron, 20.0 17 15.65 14.00 =i 95 
Protox. ae 4.6 5 8.00 7.55 5 
Oxyd of tin, 0.4 1 0.50 
Water, oor. —=99B.—=98 V. 0. 0.35=97, 9'T. 0.05= 101.75 T. ae W. 
The last analysis by Wollaston, was made with but 5 grains of the 
original specimen in the British Museum. The results of these 
analyses are not so widely different as to excite a doubt respecting 
the correctness of the conclusions from crystallographic considera- 
tions. 
There is yet much uncertainty with respect to the identity of the 
Finland Tantalite with the species Columbite. Its superior specific 
gravity, (7.2 to 7.3,) and slightly different composition, seem to re- 
quire their separation. Gustay Rose, in his Elements of Crystal- 
lography,* p. 168, has proposed this separation on crystallographic 
grounds, and has included, as above, the Bodenmais and ‘ Massa- 
chusetts” (Connecticut?) specimens in the species Columbite, and 
those from Finland under the separate name of tantalite. It would 
appear, however, that he was not acquainted with the crystallization 
of the American specimens; for he arranges the species Columbite 
* Elemente der Krystallographie nebst einer tabellarischen Uebersicht der 
nach den Krystallformen, 174 pp. 8vo. with 10 copper pls. Berlin, 
