G. J. Brush’s Mineralogical Notices. 65 
will be seen from the following table containing the measure- 
ments of several crystals numbered 1 to 6. 
No. Inclination of base on Prismatic face(Z) on | J on base, over 
> sy 3 ee ee 3: (app S242 
1 |135° 30/1379 = [135° 10/1359 : 133°|135° = |134940' 909/909 40’ 
2 |133° 20' 135° 134° 134° 30’ |g7e 9° 20 
3 {139° |138° = | 135° 20//135° 20" 130° 134° 40’ 90° 
4 |135° 135° 134° 40" 134° 20! ~ 
5 138°  |135° 40" 131° 899/919 
6 (1379 135° 4 135° 
The planes of the S gps amid at one end the prism are num- 
bered }, Nm 8; = 2b, 36 in order around ; ing opposite 
as terminated at both ends, te while the inclina- 
tion of he oat face [on 1 at one end was 130° , (as stated 
above,) the same J on 1 at the other end was 184°380. The 
“prismatic face J” referred to in the table is in each case that 
plane of the prism which is in the same vertical zone with the 
Epa plane mentioned. In — . 2, 3, 4 and 6, the angle 
tween the faces of the prism was 
Many of the aelipet have a perf cleavage parallel to the 
eavage being equal and like in 
queaiy the compact waxy fracture of the uncleavable None 
lucent. Hardness - =o96, 8 pecific gravity 2 736378 Be- 
pie the Asry ke Kenai Ber: and fuses to a white 
amel; in the ae caps gives alkaline aed a with salt of 
phosphors gives reactions for silica and iron. by 
acids without gelatinizing. The powdered cent ke heated over 
a blast lamp in a ae aati crucible » eee to a semi-fused 
mass which can no longer be decomposed by 
As the crystals vary so oa od rio’ crystallographic 
physical characters I ex da like variation in dete 
chemical composition, and in eee to test this point three speci- 
mens differing pmisrennsina in ap nee were selected, and a 
complete analysis was a 
Qualitative examination showed the presence of silica, alumina 
from the mineral as selected for analysis. 
‘ arate + Bipes quantitative determinations, the mineral was decom- 
: . y carbonate of soda; the pcalies were determined by 
: h’s method. In one case the water was determined directly 
SECOND SERIES, Vor. XXVI, No. 76.—JULY, 1858. 
9 
