316 Progress of Foreign Science. 



M. Vauquelin, may put geologists in the way of imagining the 

 origin and mode of formation of this singular mineral produc- 

 tion. The discovery of a quantity of this stone, of good qua- 

 lity, would be of great importance, adds he, to the goldsmiths ; 

 for it is rare, and extremely high priced. 



Analysis. First Specimen. Second Specimen. 



Silica .... 85.00 69.00 



Alumina .... 2.00 7.50 



Lime 1.00 a trace 



Charcoal .... 2.70 3.80 



Sulphur .... 0.60 a trace 



Metallic iron . . . 1.70 17.00 



Moisture .... 2.50 97.30 



Loss 4.50 



100.00 

 Ann. de C/iini. et de Phys. xxi. 317. 



12. Examination of an Aerolite which foil in the 7ieighbour' 

 hood of Epinal on the 13<A Sept. 1822, at the entrance of the 

 forest of Tau7ii^re, three quarters of a league from la Baffe 

 (Vosges.) By M. Vauquelin. 



This stone is in appearance like the ordinary aerolites; but 

 is distinguished by the great quantity of metallic iron, and the 

 small quantity of sulphur that it contains. By acting on its 

 powder, with muriatic acid, and transmitting the evolved gas, 

 through solution of acetate of lead, slightly acid, he had a pre- 

 cipitate of sulphuret of lead ; from whose quantity he inferred 

 that of the sulphur present. What was insoluble in muriatic 

 acid, he washed on a filter, and afterwards calcined with caustic 

 potash. The fused matter assumed a greenish tint. The mu- 

 riatic solution was treated with gaseous chlorine, to peroxidize 

 the iron, which was then thrown down with ammonia. From 

 this precipitate, he separated the manganese and the minute 

 quantity of magnesia, which might fall along with it by sul- 

 phuric acid. The following are the results on four grammes : 



Id 100 parts. 



Silica 1.40 35.00 



Oxide of iron .... 2.51 62.75 



Sulphur 0.09 2.25 



Oxide of chromium . 0.01 0.25 



nickel . , . 0.02 0.50 



Magnesia 0.17 4.25 



Lime and potash . . 0.50 1.25 



4.70 Toa25 



The 2.51 parts of oxide of iroa correspond to 1.76 of metal ; 



