PHYSIOGRAPHY. 



Red Lead-Ore Red Silver. 



159 



2. Analysis. 



By PFAFF. By BERZELITJS. 



Oxide oflead . . 68-00 . . . 68-14 



Chromic acid . . 32-00 . . . 3186 



3. Red Lead-Ore has been found in Siberia, in the neighborhood of 

 Beresof ; where it occurs in narrow veins, traversing a rock, the true 

 nature of which is not ascertained. It is accompanied by cubical crys- 

 tals of Iron Pyrites, generally in a state of partial decomposition ; also by 

 Galena, several salts of Lead, and sometimes by Native Gold. In Bra- 

 zil, it is met with in sandstone, probably under similar circumstances, 



RED SILVER. Red M a lacone -Blende. 

 Primary form. Rhomboid. P on P = 108 39' 39". 

 Secondary forms. 



Fig. 380. 



Similar to those of Proustite, (q. v.) and several others 

 resembling the secondary forms of Calcareous Spar. An- 

 nexed is a crystal, measured by PHILLIPS, which com- 

 bines the principal modifications, under which Red Silver 

 is seen. It is obvious from an inspection of the figure, 

 that the planes z tend by their extension to the production of 

 an obtuse rhomboid ; the planes g, to acute rhomboids ; 

 the planes d, and the four planes without letters, situated 



