158 Crystals of Topaz. - a 
the Chesterfield Rubellite. It is translucent on the edges, 
-and exhibits a very feeble lustre. It is so soft as to be 
scratched by a quill, is fragile, ot emits a strong argilla- 
eeous odour when moistened, es not adhere to the 
tongue. Its specific gravity is ae 2.2. & 2.5. Before 
the blow-pipe, it immediately whitens, and melts into a pear- 
ly superficial enamel. 
Ill. Measurements of Crystals of — from Huntington, 
Conn. ; by Cuas. U. SHEPARD. m a fine collection of 
Huntington ‘pies, obligingly put =e my hand by Prof. 
Silliman, I have measured several crystals with the reflective 
goniometer. Annexed are figures of three of the most per- 
fect 1 examined, with the measurements obtained. These 
erystals were well defined, and perfectly transparent; and, 
from the pains I took to be exact, I trust that my measure~ 
ments of their angles, are very close approximations to their: 
true value.- 
~ - § 124° 20% 
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