1895.] Mineralogy. 993 
hence a variation in the depth of the color, called by v. Federow 
pseudodichroism, is observed when the stage is revolved. Of use in 
distinguishing pseudodichroic substances from truly dichroic substances 
is the fact that the former always show brown shades in the centre of 
the field. 
Meteorites in Field Columbian Museum.—Farrington has 
prepared a “ Handbook and Catalogue of the Meteorite Collection” of 
the Field Columbian Museum? modeled somewhat after Fletcher’s 
admirable handbook describing the meteorites in the British Museum 
collection. The popular introduction is well written, with reference 
for the purpose of illustration to catalogue numbers of typical speci- 
mens in the collection. Thisimportant collection includes 180 falls or 
finds and the aggregate weight of the specimens is over 4700 lbs. With 
the exception of the Canon Diablo specimens, the largest specimens of 
the collection, are those from Kiowa Co., (Kan.), (466 and 345 Ibs.) 
and the Phillips Co., (Kan.), meteorite (11843 lbs.). The list includes 
355 numbers which are described with considerable detail. Six excel- 
lent plates illustrate typical structures. 
Crystallography of Wisconsin Minerals.—In a Bulletin of 
the University of Wisconsin, Hobbs” has studied the Wisconsin min- 
erals crystallographically. The specimens are chiefly from the zine 
and lead region of the southern part of the State, where they occur 
in the cavities of limestone, the principal species being calcite, smith- 
sonite, cerussite, galena, sphalerite, azurite, malachite, barite, gypsum, 
chalcopyrite, marcasite and pyrite. Four generations of calcite are 
distinguished by different habits as well as by slightly different colors and 
degrees of translucency. These four types appear in scepter-like par- 
allel growths. The new form 24R (24.0.24.1) has a large development 
on two of the types. At Mineral Point and Highland galena appears 
in hopper-shaped octahedral as well as arborescent aggregates, and 
individual crystals show polysynthetic twin lamellz according to the 
laws, (a) twinning plane a face of the octahedron and (b) composition 
plane a face of the dodecahedron. On sphalerite from Galena, (IIli- 
nois), the new form (775) was observed. The azurite of Mineral Point 
exhibits the new forms (307), (203), (205) and (9.12.8). The“ angle- 
site” from Mineral Point is found to be selenite. Some new crystal 
habits are observed on marcasite and on cerussite. 
° Field Columbian Museum. Publication 3, Geol. Ser., Vol. 1, No. 1, pp. 64, 
pls. 6, (1895). 
10 Bull. Univ. Wis., Sci. Ser., Vol. 1, No. 4, pp. 109-156, pls. 4-8, (1895). 
68 
