434 Scientific Intelligence. 
tion III may also fall into the same category ; so that Sections I, Il, ms 
may form a single homa@omorphous Group. 
(2. ) Sections V and VI have the same relations to one another as itl 
fe! IV, and may constitute a Second yaaa ri s Grou 
(3.) ‘In this Second Group, the basal angle of the fundamental pie 
mid, 1, is near 109° 28’, and the pyramidal angles also; or in other 
words, the furm ee to the monometric octahedron, as is 
been often observ 
(4.) In the First Grou up, the basal angle of the fundamental pyra- 
mid, taking Section Il as the type, is near 90°, or varies between 82° 
and 86°. 
(5.) The first of the two Groups of Dimetric species, corresponds 
in ea ttcheet dimensions with Section V (or Group II) of the flexago- 
nal System, and the second most nearly with Section 1V (or Group 1) 
of the .. see It remains to be shown how far this rela- 
ed it from Mr. Semann, Naturalist at Paris, who has owed me the 
pleasure "of examining it. The following are its character 
Crystals 1 to 2 millimeters oman clustered in a group. Form a right 
2 ah, octahedron, with the sal edges truncated; cleavage none. 
eral deep black ; but sone of the smallest crysials have an olive tint with 
chatoyant bichen: like lustre. Translucent on the edges, and the color 
by transmitted light, brown, inclining tored. Ona ouriaies of fracture, 
the color is zoned with straw yellow, reddish-brown and black ; and 
nearly clear at middle; the brown and black colors are deepest at the 
extremities. Powder pale brown. Surfaces of the crystal, although 
shining, are generally striated, rugose, and present numerous little cave 
pa craiches calcite, and is scratched by fluor: specific gravity at 
Vertleal prism M, 116° 25/; brachydome (top angle) 122° 6’; octa- 
hedron, 127° 10’, 88° 18’, 115° 10’, the last angle over M. 
ented j ina eh he little moisture is disengaged at an incipient red 
heat. B.B. on charcoal it melis, and is partially reduced toa 
of metallic lead enveloped ina black scoria. Afler cooling on char- 
in the reduction flame a glass of a ay chrome-green color, W 
comes orange-yellow in the oxydation flam 
Dissolves in the cold in nitric acid dikited” with 6 times its volume © : 
water, and leaves a residue of brown oxyd of manganese, mixe ed wil 
B reste quantity of siliceous sand from the gangue; the so solution Is 
color On adding sulphuric acid to it, affords an immediate prec ip- 
itate of sulphate of lead. » . 
