» 
oh x! 
* 
: 4. 7 Prehnite. _—The Anh fidrous Prehnite of J. D. bees 
E Jour. Nat. Hist., v, 487,) has beet examined by Dr. C. T. tig 
und. to contain the same per-centage of a as prehni in 
ie ifials, he found 4°7 and 4°15 per cent. of ae and iinete, 
4:18, 4:45, 4:50, 4:41 per cent. Other specimens examined b 
Mr. Gi. Brush in the Yale Laboratory, afforded 4 4: 913, 4817, 4°864 per 
nt. This mineral appears therefore to be identical with ordinary 
prehnite... The existence of water in this variety was first ascertained 
ina blowpipe experiment by Mr, J. E. Teschemacher of Boston. 
n a new crystalline form of Staurotide, 
and SevibPehiom of rateesip ns with Andalusite 
and Topaz; by J. D. Dana.—The accompa- 
nying figure, soviet crystals of staurotide 
from the spodumene locality, Norwich, Mass 
ter are as follows :—— 
N ce} 
oN oz 
. = aren N) =93° 
N :b 
ae (129° — 182°) 
The crystals are black and semi-metallic in lustre. The largest are 
14 inches in breadth. 
The isomorphism of this species and andalusite is sufficiently close 
to merit attention 
- Calculating from N : N=129° 20’, the prism b?=93° 8’. In Andal- 
usite, the prism oe ek to the latter is 91° 20’, and this gives for 
the former 127° 57’. P: Staurotide =131°, in andalusite 144° 50’; 
and the planes have chetetles the axial relation o 
For the relation of topaz and andalusite, see last vali of this Jour- 
nal, p. 407. 
The atomic volume of the St. Gothard staurotide, calculated from 
one of Ja to (4414+1¥e)? Si, and specific 
gravity 3°74, gives for. the A atomic solaias 536, and for the C atomic 
volume 38-3: for a St. Airolo staurotide, with the formula (44l+ 
$¥e)?Si?, and specific gravity 3°7, we obtain the A atomic volume 
890-5, the C value 38-7. Andalusite afforded (last volume of this Jour- 
nal, P. 235) A = 962°5, C—=41°85; and topaz (loc. cit., p. 240) A= 
6. 
=4 
6. Platinun of California.—In a letter from J. E. Teschemacher, 
we are informed that he has detected a oe of platinum among 
- Fowlerite—This name, applied to a variety. anganese spar 
or thodonite, was not originally eA by Prof. Gaetan, as stated 
on p- 410 of last volume of this Jou 
See fen, Vol. X, No. 28. — 1850. 16 
“% 
Priests, and isdéey: 121 
