at Lemington Priors. 361 



the whole inftantly evaporated with a denfe fmoke. I mixed, 

 therefore, another portion (proeured in the fame manner)' 

 with alkali, and heated them in a crucible : ftill I failed to 

 colled any fulphur from the alkali (as I had hoped) ; but I 

 now perceived that, as the crucible became hot, the matter 

 burnt away with a blue flame, as fulphur does. 



" Sulphat of argill is not decompofed by this water when it 

 has bcjn reduced by evaporation : however, it gradually fe~ 

 parates fome of the abundant fulphat of lime; which is pro- 

 bably caufed by its attra&ing the water which held it in 

 folution. 



" I think it right here to obferve, that I have recently met 

 with this water in fuch a condition that it caufed a perma- 

 nent decomposition of fulphat of argill. This precipitate is 

 extremely minute : I have not as yet determined the caufe 

 of it, but I fufpect it to be carbonat of magnefia." 



V. Second Memoir on the Metal contained in the Red Lead of 

 Siberia. By Cit. Vau^UELIN. From the Annales de 

 Chimie, Vol XXV. 1798. 



I 



HAVE already {hewn in my firft memoir * on the 

 red lead of Siberia, that this mineral contains a parti- 

 cular metal, which I promifed to examine with more atten- 

 tion. The Council of Mines having furniihed me with a 

 pretty large quantity of the red lead, confidering its fcarcity, 

 I have been able to make a feries of experiments fufEcient 

 io determine its principal properties, of which I (hall now 

 give an account; but it will firft be neeeflary to recapitulate, 

 hi a few words, the fubitance of my former memoir, in order 

 that what I have to fay at prefent may be rendered more in- 

 telligible. 



I. I (hall obferve, that on boiling the red lead reduced to 

 i. pwvyJer with two parte of the carbonat of potafh, the lead 



9 fe? Page *79- ,. 



t;ombme« 



