64 Scientific Intelligence. 
for both types; thus in spe II the eae identified on chondro- 
dite are A, B, C, +r, -+ir, —}r, —47, n, yn, —m, t, e, Ze, etc. Type 
_~ chondrodite, +r, +4, +41, -—ir, — Fr, —7r, 2, An, Hn, 7, H 
. addition to these prominent planes, I have measured, 
more or less surely determined, upwards of a hundred other nlanel 
very minute, and yet flat and giving in many cases perfectly relia- 
ble angles. As would naturally be expected, the indices of these 
planes are in general anything but simple. e. discussion of 
these, and the description of other —_ pp interest which have 
been observed, including several twins, t be deferred till the 
final completion of the memoir, which, sie is eee will not be long 
delayed. 
11. Livingstonite—This nents recently described by Sefior 
M. Barcena (see this Journal, last vol. p. as been analyzed — 
by its describer with the fo ae results : Sulphur 29°08, anti- 
mony 53°12, mercury 14°00, iron 3°50 = 99°70; whence a atomie 
ratio for the oe reas: antimony, mercury and iron 18°17 : 
1-2. =-(nearly) 1 
The livi auton: occurs : Huitzuco, in the State of Guerrero, in 
a matrix of carbonate and sulphate of lime, along with native 
sulphur, cinnabar, valentinite and stibnite. The rs pis mentions 
phous. 
2, On Dawsonite, a new mineral; by B. J. Hanae 
Chemist and Mineralogist to the Geological Survey 0 Can. 
(Canadian Naturalist, vii, August, 1874.)—Dawsonite is from 
whitish felsitie dike near the western end of McGill College, — 
Montreal. Hunt obtained for the rock (which he calls trachyte), 
contained: Silica 1:43, alumina 2°43, peroxide of iron 2°40, 
oxide of manganese 1°31, lime 0°60, potash 0°40, soda 0° 98—9: 55. 
In the joints of this rock occurs a white-bladed mineral, which i8 — 
the Dawsonite. : 
The following are its characters. Hardness 3; G=2°405 — 
luster vitreous ; “transparent to translucent. The blades are some : 
what fibrous in structure, and the orpstalinasion: Sieh 2 bly 
monoclinic, with the on eres of the vert bout 75 
It shows bands of colors in polarized li ht. “a B. becomes — 
ohegne and often exfoliates or swells into cauliflower-like forms. : 
In the closed tube yields water and carbonic seid. Dissolves — 
maples in cold dilute hydrochloric or nitric acid. Iwo 
analyses, made at different times, the last from portions of several — 
specimens, afford Mr. Harrington— : 
Si 6 Al Mg Ca Na K H 2 
0°40 29°88 32°84 tr. 5-95 20°20 0°38 11°91=101°56. — 
30°72 32°68 0°45 5°65 20°17 [10°32 ]=100. 
