SiO, AIO3 MgO B.Os P,05 H,0 
27.99 64.49 tr. 4.95 .20 1.72 
equivalent to 3 AI3 SiaO^H + Al (BO,), + 2 H,0. Damour,' who 
first analysed the mineral regarded it as a simple silicate of 
aluminuium of the formula Al, Sis Ois. — Additional observations 
upon bertrandite increase materially our knowledge of this rare 
mineral. Investigations by Urba" upon the crystals coating 
the faces of feldspar from Pisek, Bohemia, and the walls of 
cavities in this mineral yield results analogous to those obtained 
by Penfield' in the case of the Mt. Antero crystals. Accord- 
ing to Urba^: b \ c^=-jig\. : 1 : 4206. In addition to the 
cleavage parallel to 3Poo~ Urba finds also a very perfect one 
parallel to oP. The new plane > P^ is also discovered. 
Analysis of the Pisek mineral gave : 5102^49.90, BeO= 
42.62, H„0=7.9_4. The Mt. Antero crystals* are bounded by 
the three pinacoids. Of the two basal planes one is flat and the 
other rounded in consequence of an oscillatory combination 
with a brachydome. The distribution of the electrical proper- 
ties of the crystals show them to be hemimorphic, as indicated 
by the oscillatory combination on one only of the basal planes. 
The mineral has recently been discovered at Stoneham, Maine. 
Mr. Penfield'has examined crystals from this locality and has 
identified on them the planes oP, i^ P5^, 3 PS5', 00 P^, and 
00 P3. The crystals are double wedge-shaped, are hemimorphic 
in the direction of their vertical axis, and are elongated parallel 
to the brachy-axis. One twin with oP as the twinning plane 
was observed. A calculation of the axial ratio gave « : b: c 
^.5973: I : .5688. — Pisani' has analysed <;;//'r^-«f£'.yc/f'mV^ from 
Zacatecas, Mexico and has found in it: 
VdA AsA PbO CunO ZnO H,0 
17.40 4.78 53.90 8.80 11.40 3-20 
The mineral has a brown color on a fresh fracture, and a spe- 
cific gravity of 6.06. — A new analysis of the very remarkable 
mineral vtelanophlogite has been made by Pisani.' The min- 
eral was found in little colorless cubes associated with calcite, 
sulphur and celestite in a limestone geode from near Girgenti, 
Sicily. After purifying as carefully as possible it yielded: 
\ Bull. .Soc. Min. d. France. IV. p. 6. 
"■ Zeits. f. Kryst. XV. p. 194. 
