1896.] Mineralogy. 575 
molecular volume may be considered as accurately known, and allows 
of comparison between the various physical constants of this and iso- 
morphous substances. 
Minerals from the Galena Limestone.—Hobbs*® gives a de- 
tailed description, with many drawings, of the crystallized minerals 
from the galena limestone of southern Wisconsin and northern Illinois. 
The habitus of the various crystals is made prominent in the discus- 
sion of them. New forms are reported on calcite (24.0.24.1), on cerus- 
site (0.25.4), and on azurite (307), (203), (205) and (9.12.8). 
Miscellaneous Notes.—Becke’ shows that the center of symmetry 
may be used as a fundamental conception in developing the 32 classes 
of crystal symmetry, notwithstanding the fact of its abandonment by 
Groth and Fedorow.—Sylvite from Stassfurt, investigated by Schimpff” 
with special reference to the impurities of the same, gave K Cl 99.239, 
Na Cl .242, Mg Cl, .089, Ca SO, .073, H,S .0023, residue .108, loss on 
melting .2847. The foreign substances seem to occur chiefly as inclu- 
sions with the mother liquor. These figures doubtless give a very good 
idea of the amount of impurity present, but the extreme right hand 
digits must be looked upon as mathematics rather than chemistry-— 
Igelstrém™ finds molybdenum, probably present as Mo,O,, in the hem- 
atite from the “Sjégrube,” Gouv. Örebro, Sweden. One specimen of 
the same material showed spectroscopically the presence of thallium.— 
Niven” notes the discovery on New York Island of numerous interest- 
ing specimens of the rare earth minerals xenotine and monazite. Tit- 
anite, epidote, beryl and menaccanite are also mentioned.—The mineral 
named schneebergite by Brezina” on the basis of an apparently faulty 
qualitative investigation is shown by Eakle and Muthmann”™ to be in 
reality a very pure lime-iron garnet, or topazolite, instead of a calcium 
antimonite. The specific gravity is 3.838, and the chemical composi- 
tion: 
8 Zeitschr. f. Kryst., XXV, pp. 257-275, 1895. 
9 Zeitschr. f. Kryst., XXV, pp. 73-78, 1895. 
1 Zeitschr. f. Kryst., XXV, p. 92, 1895. 
1 Zeitschr. f. Kryst., XXV, p. 94, 1895. 
12 Am, Jour. Sci., L, p. 75, July, 1895. 
18 Vehr. d. k. k. geol. Reichsanstalt, 1880, p. 313. 
u Zeitschr. f. Kryst., XXV, pp. 244-246, 1895. 
