Timgstcn and Tellurium. 405 



admitting this to be the fact, there is a manifest impropriety in 

 offering to the public, as medicine, an article which cannot be 

 used as such. Probably the proprietors of this manufactory 

 are not aware of the real nature of the case, and of the facility 

 with which, by a little additional trouble, they could separate 

 the useful and valuable material, from that which is at least 

 useless, and which might also be pernicious. 



South-Carolina College, March, 1819. 



Art. XVII. Additional Notice of the Tungsten and Tel- 

 lurium, mentioned in our last Number, 



Part I. Description of the Ore. 



v^OLOUR, dark brown, almost black ; brittle, powder a 

 lighter shade of brown than the mineral ; hard, scratches glass, 

 scintillates with steel, with a red spark ; a degree of polish 

 produced, where the steel strikes, and when the steel is im- 

 pressed upon it. 



Structure compact, in some places slightly porous ; lustre, 

 generally dull, sometimes glimmering, and almost resinous. 



Crystals octahedral. Specific gravity of three massive 

 pieces, 5.7, 6. and 6.44 mean, 6.06 nearly ; probably that of 

 the crystals would be higher. 



Infasible by the blow-pipe even with borax, and does not 

 by strong ignition impart any colour to it or to potash ; not 

 magnetic, even in fine powder, nor after being heated red hot 

 on charcoal, and in contact with burning grease. 



Many specimens decrepitate violently under the blow-pipe. 

 When heated on coals in pieces of considerable size, they often 

 explode with a smart report, and are thrown in fragments 

 sometimes several yards from the fire. 



Gangoe quartz ; accompanying minerals in the same vein, 

 native bismuth, native silver, galena, iron and copper pyrites, 

 much magnetic pyrites, blende, &c. 



