1^ Scientific Intelligence. — Mineralogy. 



burg. The relative weights of the platina of Berlin, Madrid 

 and Petersburg are as 1, 11, 75. 



10. On the Ostranite, a New Mineral Species ; by Aug. Breit- 

 haupt. — This substance has only as yet been found in the crys- 

 tallized state, and in the form of a right rhomboidal prism, slight- 

 ly modified on the acute lateral edges, and deeply truncated on 

 the angles of the bases. M. Breithaupt derives this form from 

 a rhomboidal octahedron, in which the three axes are to each 

 other as the numbers 1000, 2059, and 1854. The adjacent 

 faces on the same pyramid form between them angles of 1j28° 

 14', and 13S° 42'. Their inchnation upon the base is 71° 56'. 

 The angles of the rhomboidal prism are 96° and 48°. There is a 

 scarcely perceptible cleavage parallel to the small diagonal of the 

 base. The lustre of the ostranite is vitreous; its colour is clove- 

 brown. Its hardness is intermediate between that of orthoklase 

 and quartz. It is very brittle ; its specific gravity varies between 

 4.32 and 4.40. The crystals of this substance, which served as 

 a basis to the preceding determination, were about an inch long; 

 they formed part of the collection of the Chev. Heyer, of Dres- 

 den. They came from Norway, whence they were brought by 

 M. Nepperschmidt, of Hamburg. Nothing is known precisely 

 with regard to their geognostical relations. Some trials of this 

 substance have been made with the blowpipe. Treated alone, 

 it does not melt, but its colour becomes paler. With borax it 

 melts, but with difficulty, into a transparent glass ; it is insoluble 

 in nitric acid. From these characters^ and the place which it 

 occupies in the system, M. Breithaupt presumes that this sub- 

 stance is a new metallic oxide. He gives it the name of ostranite^ 

 derived from that of the goddess Ostra, in order that, should a 

 new metallic base be discovered in this oxide, the name of Ostran 

 may be given it, as has been done with regard to titanium and 

 titanite, tantalum and tantalite, &c. 



11. On the Rose-coloured Pctrosilex of Sahlberg ; by M. Ber- 

 thier. — M. Berthier proposes to submit to a chemical examina- 

 tion the petrosilex of Sahlberg, in Sweden. This mineralogist 

 observesy that the petrosilexes are erroneously considered as va- 

 rieties of compact felspar. It -is one of those vague denomina- 

 tions with which science is still disfigured, and which only serve 

 to lead into error, or to deceive us with regard to what we are ig- 



