J38 M. Wohler on the Composition of the Phosphates, fyc. 



ved in nitric acid, was precipitated by ammonia, and an excess 

 of the hydrosulphuret of ammonia was then added. The sul- 

 phuret of lead, after being collected on a filtre and dried, was 

 decomposed by concentrated muriatic acid; the chloride of 

 lead was then heated to redness, and weighed. The quantity 

 of the phosphoric acid was inferred from the loss. The com- 

 position of the mineral, according to this analysis, is, 



Oxide of lead, 

 Muriatic acid, 

 Phosphoric acid, (and a trace of iron,) 



Or, 



Chloride of lead, 



Sub-phosphate of the oxide of lead, 



The other specimens were analyzed by a similar method, 

 and the composition is shown by the following table : 



White Lead. Arseniate of Lead Lead-Spai 



Spar from from Johann- from Lead 



Zschopau. Georgenstadt. Hills. 



Oxide of lead, 80.55 (with a trace of iron,) 75.59 82.46 



Muriatic acid, 1-99 1.89 1.95 



ii -.„« oi ™ fand of iron, 



Arsenic acid, 2.30 21.20 | a tracej 



Phosphoric acid, 14.13 1.32 15.50 



98.47 



Or, 



Chloride of lead, 10.09 

 Sub-phosphate of ) gQ „_ 

 the oxide of lead, 5 

 Sub-arseniate of ~f . „. 

 oxide of lead, 5 





99.47 98.91 



The presence of muriatic acid was also detected in several 

 minerals of the same species ; namely, in the green lead-spar 

 from Freyburg in Breisgau, from Beresofsk in Siberia, and 

 from Clausthal in the Harz ; in the brown lead-spar from 

 Poullouen in Brittany, and from Rheinbreitenbach. The 

 muriatic acid is very easily detected in these minerals by Ber- 



