194 ANNUAL KECOKD OF SCIENCE AND INDUSTRY. 



MAXITE, A NEW LEAD ORE. 



A new lead ore, lately discovered in Sardinia by Max 

 Brown, is said to consist of a hydrated sulphato-carbonate of 

 lead a compound entirely novel in the mineral kingdom. 

 The new ore is to be called Maxite, as the name Brownite 

 had already been appropriated. 16 A, October, 1872, 521. 



THE CKUST OF METEORIC STONES. 



Simultaneous but entirely independent investigations by 

 Professor Reinsch, of Tubingen, and Meunier, of Paris,led them 

 to the conclusion that the black crust of gray meteoric stones is 

 not the result of fusion during their passage through the atmos- 

 phere. The Krahenberg meteorite was examined by Profess- 

 or Reinsch, and his results communicated at the German 

 Scientific Association during its recent meeting at Leipsic. 

 Microscopic examination of thin sections of the crust showed 

 that it was composed of two entirely distinct portions. The 

 external, highly porous layer, filled with channels and cavi- 

 ties, seldom contains metallic iron, magnetic pyrites, or other 

 minerals ; while the interior, highly lustrous, compact layer, 

 decidedly distinct from the gray granular mass of the stone, 

 often incloses metallic iron and magnetic pyrites. In rare 

 cases particles and laminae of metallic iron penetrate both 

 layers, and are slightly changed by oxidation as far as they 

 extend into the outer layer. The ground mass of the stone 

 consists of particles, more or less spherical, of a light or dark 

 gray material (silicate of magnesia), in which metallic iron, 

 magnetic pyrites, and different silicate minerals (the latter 

 without distinct crystals) are imbedded without any recog- 

 nizable order. The globules generally are made up of sev- 

 eral minerals ; but even when they contain only one they ex- 

 hibit under the microscope small inclosed masses of magnetic 

 pyrites, either in isolated aggregations or filling vein-like fis- 

 sures. When simple in structure, they are perfectly spherical ; 

 but when more complex, less spherical; and in the latter case 

 the different substances are not arranfjed accordins; to their 

 specific gravities. The iron and magnetic pyrites, when both 

 are present, are generally found in the external, seldom in the 

 central parts. Professor Reinsch therefore concludes that 

 these meteoric stones could not have been at a red heat, even 



