’ 
Fifth Supplement to Dana’s Mineralogy. 401 
observatio: i ag to 121°.—Another St. Gothard specimen, ¢ =1:5243, 
Ba=1-5293,” y=l5181, whence 2V=699 1’, 2E=119° 11’; mes observation 
gave 2E=119° 35’. The same specimen varies in different parts Moon- 
____ stone identical with orthoclase. 2 
_ Beolecite—/: eal 36°: —— e parallel to 74; cree usually — about 
ti. Plane of axes perpendicular to i-2, making an angle of 10° to 11° with the 
plane of S apsciiicen Bisectrix inclined. 10° to 11° “ the edge (J: ), 2E=60°. 
Borax.—J: J=87°, Plane of axes normal to i-i, varying for the violet and red rays ; 
, and 85° 10* to mal 
a for the cg high ed 108° 35’ toa al to O 3 r t 
#4; for the latter these angles are 106° 85’ and 33°10’. Bisectrix normal to #4. 
oy p arent mean nangie 59°, S RO index 1: 
| Datholite I: F=i6° 44", 0; f=290° ; plane of axes parallel to i+. Bisectrix: 
___ sensibly normal t 0. 
auberite.— I: J==83° O: I=104° 15’. From 0° C. to 30° C., plane of axes 
normal to i-? and almost normal to O; at 30°, the two are ante for white light; . 
towards 85° C. the separate anew, but their plane i is then  poreliel to 7-2. e 
ectrix nag hs its prim mitive position. 2V varies from 0° to 8°, Brewster. 
Glauber. Salt—1: T=80° 24’, QO: it==107° 44". Plane of axes her nasadse cular to 7-2, 
if inclined 199 24’ to ‘ ines to ii. Bisectrix normal to é-2 and parallel to fete: 
diagonal ; g=1- pas Miller 2F—=80° 26’. Observed for 2E 118° to 119° 20’, 
which gives 73° 8u’ QV. 
C. Crystallization Triclinie. 
Kyanite—O :1-i=100° 50’, O:i-4=98° 15/, £1: 1-X=2106° 15’. Plane of axes nor- 
Fina to #- 2, a about 30° to the edge (i-2: J’). Bisectrix normal nearly to 7-1, 
dtp tapi of fa egeres.- Margarite, Gilbertite, Astrophyllite, An- 
nt te (2E==10° 12°). 
| pon this any ect of dopihhacns refraction in minerals font as = hes dichroism), a 
rer valuable e able, containing additional details, m railich’s trans- 
tion (into G ) of Miller's Copeteliogenehy. 6 entit ed. . oe Lebebuch der Krystal- 
the phie,” ssatlished in 1856 at Vienna. table occu Ps es of the work ; 
"Me optical characters of many artificial Be te Po included in it. 
Formation of Minerals —Daubrie (Lfstitut, 1857, 379) wy; subjecting gla moder 
Pressure to the action of water at a high tem re (400° C.) has cha 
aia; was no 
yy under the same circumstances eval eldspar erysta 
hg like trachyte; and tect us glass, aff nana pate the ae tals regularly 
“bs al dt transparent and of the usual green color. Hence, steam un nder high press 
mnt that is ecessary in connection with the rock material of the globe to poe 
many of the rock erystallizations, even to the ingredients of granite. 
Descriptions of —— 
Acatmatonrre [p, 252, 976).*—Dr. C. T. Jackson n fo agelineee ite, a rock 
rich & soapy tol core N. 2 oe lina (Am. J. Sei, a v, 973). ysis afforded, 
1500 “ar: 
wn eel i =9 ith —- - oxyd ea ae 
A ile oe gt A H 350=—' vrei wil aoa iated with 
bbro, afforded O. F. Chandler (Inaug. * Dieusat Bi 15: 28, Zi 13-43, Be 188, Mg 
9, % r (ine 
The Soe K 454, H 2-49=99 78. fa deal 5 Conde was shown some 
ot. XXV, No. 75.—MAY, 1858. 
