MINERALOGY. 223 



Baumhauer, H. Die Aetzfiguren am Lithionglimmer, Turmalin, 

 Topas und Kiesclzinkerz. [Erosion-figures on Lithia-mica, Tour- 

 maline, Topaz, and Silicate of Zinc.] M. Jahrh. Heft i. pp. 1-8, 

 plate i. 

 Lepidolite from Zinnwald, acted on by fluor-spar and sulphuric acid, 

 exhibits erosion-figures which appear to be triclinic. After many- 

 fruitless experiments a black tourmaline was etched with fused caustic 

 potash, the character of the figures agreeing with the hemimoi-phism 

 of the crystal, llhombic impressions were produced on the two parallel 

 basal pinacoids of crystals of topaz, thus tending to prove that this 

 species is not hemiraorphic. Silicate of zinc from Altenberg was treated 

 with warm hydrochloric acid, and a face of ocPgo showed figures which 

 agree with the hemimorphism of the species ; but to show the corre- 

 spondence between the form of the figure and that of the crystal it is 

 necessary to invert the position of the erosion-figures. F. W. R. 



[Erosion-figures on Pyromorphite, !Mimetesite, and Vana- 



dinite.] N. Jahrh. Heft iv. pp. 411-413. 

 The crystals were etched with warm dilute nitric acid. Pyromorphite 

 from Pleistadt (Bohemia) exhibited very fine pyramidal-hemihedral 

 structure ; and it was less marked in crystals of the same species from 

 other localities. Mimetesite is also shown to be pyramidal-hemihedral ; 

 but no definite results were obtained from the crystals of vanadinite, 

 which were very small. F. W. R. 



. Die Aetzfiguren am Adular, Albit, Flusspath und chlorsauren 



Natron. [Erosion-figures on Adularia, Albite, Fluor-spar, and 

 Chlorate of Soda.] N. Jahrh. Heft vi. pp. 602-607, plate. 

 Treated with fluor-spar and sulphuric acid, crystals of adularia ex- 

 hibited figures which exactly corresponded with the symmetry of the 

 monoclinic system ; while albite showed markings corresponding with 

 the symmetry of triclinohedral crystals ; fluor-spar etched with sul- 

 phuric acid showed depressions which were probably referred to mOm 

 and mO. F. W. 11. 



Beck, W. von. Ueber cine neu entdeckte Lagerstjitte von Silbererzen 



im Troitzker Bezirk des Gouvernemcnt Orenburg. [New Deposits 



of Silver Ores in the Government of Orenburg.] N. Jahrh. Heftii 



pp. 162-170. 



A quartz vein, running through crystalline schists, is bounded by 



ochreous saalbands, which contain compounds of silver with chlorine, 



bromine, and iodine. Two other silver- bearing veins occur in the 



neighbourhood. The haloid combinations of silver in these llussian 



veins resemble those of South America. F. W. R. 



Bergstrand, C. E. Bidrag till kiinnedoracn om den 1 Wemdalcn 

 fiirekommande vivianiten samt andra i samband denned upptrii- 

 dande jordaflagringar. [Vivianite and other associated Ores in 

 Wemdal.] GeoJ. Foren. StocJcholm FOrh. Bd. ii. pp. 335-340. 



Two analyses are given. 



