556 Clironicles of Science. [Oct., 



in several crystallograpliic directions.* Small rectangular prisms 

 were cut from the salt of Stassfurt, having their axes normal to the 

 faces of various crystalline forms. The tenacity of the prism was 

 then determined by attaching a scale-pan, and loading it until frac- 

 ture occurred. It was thus found that the prism always broke 

 along a plane parallel to the face of a cube, but that the breaking 

 strain varied considerably, according to the direction in which the 

 prism had been cut. 



In working the Jacobsgliick lode at Andreasberg in the Hartz, 

 a peculiar and extremely rich argentiferous sand has lately been 

 found.t The lode contains many drusy cavities irregular in shape 

 and variable in form, the larger ones being usually empty, whilst 

 the smaller ones are filled with sand. By examination under the 

 microscope and before the blow-j)ipe, this sand is found to contain 

 native silver in minute octohedral crystals, and in scalenohedral 

 forms probably pseudomorphous after calcite. It is notable that 

 silver does not occur crystallized elsewhere in the Andreasberg 

 district ; while, on the other hand, red silver ore, which is a common 

 mineral in the veins, is absent from the sand. The pulverulent 

 material contains, however, chloride of silver in very small cubes ; 

 and this, strangely enough, never occurs crystallized in the mines, 

 and is, indeed, a rare mineral in the district. Calcite, quartz, and 

 a yellow amorphous mineral not yet determined, complete the Hst 

 of constituents of this true " silver sand." 



Among the many rich gold-bearing veins of the Maldon IMinmg 

 district in Victoria, few have excited more interest than the " Nug- 

 getty Eeef." Mr. Salter, the manager of the Alhance Company's 

 mines, has detected in this lode a peculiar metallic mineral, wliich 

 in the hands of Mr. Ulrich turns out to be a new species.| Mal- 

 donite — as we are to call it — occurs as a silver-white, slightly 

 pinkish mineral, with a bright metallic lustre rapidly tarnishing. 

 It is softer than pure gold, very sectile, and exhibits apparently a 

 cubic cleavage. Its chemical examination showed it to be an alloy 

 of bismuth with gold. 



From the copper mines of Namaqualand Mr. Gregory has 

 obtained a mineral, which Professor Chiu'ch has described under 

 the name of Namaqualite.^ It occurs in thin layers made up of 

 short silky fibres, exhibiting a pale-blue colour, and consisting, 

 apparently, of a " cujiric alumiuic hydrate," thus formulated : — 

 Al, Ho 0,. 3 Cu H, 0. 4 aq. 



Jakohsite is Damour's name for a new species related to the 

 spinel grou]?, found in the mines of Jakobsberg, in Wermland, 



* Poggendorif's 'Anualen.' 1809. No. 6, p. 177. 



t Leonhard u. Broun's ' .Talirlmch.' ISO!), p. 445. 



% ' Notes on tlic Nii^r<;<'tt.v !{«■( T,' IMiildon, Yiftoria. By G. II. F. Ulricli, F.G.S. 



§ ' Chemical Now.s,' July ;{(», 18»;!>, p. 53. 



