438 " Brown Lead Ore of Zimapan. 



rable repute, and is conveyed, in some quantity, over the Alle- 

 ghany mountain, to the iron works, eastward. 



Fossils are not very abundant in the coal measures. Impres- 

 sions of flags and reeds may be noticed in all the sandstones, 

 even almost up to the western summit of the ridge ; and ferns 

 occur in the shales near the coal veins. Hollow cavities, for- 

 merly occupied with producta, and a few other species of co- 

 temporary fossils, are occasionally to be seen in every part of 

 the sandstone series, within the coal field. 



THE BROWN LEAD ORE OF ZIMAPAN. 



Communication from Professor Del Rio, on his discovery of a New Metal 

 in the brown Lead Ore of Zimapan. 



I should not again have brought forward my analysis of the 

 brown lead ore of Zimapan, which now rather redolet antiquita- 

 tem, if the interest excited about the metal, called by some che- 

 mists in Europe, Vanadium, — after, as it is said, some Scandina- 

 vian mythological personage, — had not induced one of my friends 

 to ask me to translate the passage concerning my analysis, froni 



my Spanish translation of the mineralogical tables of Kersten, 

 printed at Mexico in 1804, and which passage 1 here subjoin. 



"Having distilled half an ounce of the brown lead ore three or four times 

 with diluted sulphuric acid, and washed the residuum every time, I got a 

 green solution, which, being saturated with excess of ammonia, gave, in a 

 few days, crystalline crusts formed by needles on the surface of the liquid, or 

 stars, composed of very acute pyramids, on the sides of the cup. These 

 white crystals being washed with some water and dried in the air, became a 

 most beautiful scarlet red as soon as they were touched by a single drop of 

 an acid somewhat concentrated. When diluted, they became at first yellow, 

 and afterwards red. These acids* dissolved them without decomposition. 

 I experienced the same with potash, soda, and lime, excepting that the 

 rhombohedrons of potash only became yellow. The excess of ammonia be- 

 ing saturated with nitric acid, and concentrating it somewhat by evaporation, 

 I got square prisms, pointed, with four faces upon the edges, of a pretty aurora 

 red, the taste of which was pungent and metallic. The same was done with 

 soda, and I got squares of a red colour, and oblique sided ones with potash, 

 and of a yellow colour. 



" Having put in a porcelain test below the muffle, 17.75 grains of the 



* As far as I remember they were the sulphuric and nitric. — Jl. D. Rio, 



