348 Mr. Gregor's Experiments on a mineral Substance, See. 
( 3. ) Some perfectly pure crystals were dissolved in muriatic 
acid. Some silica was separated. A few drops of sulphuric acid 
were dropped into the solution, which produced no immediate 
change : on evaporation a white powder separated, which con- 
sisted in part of sulphate of lime. The remainder, exposed to 
the flame of the blowpipe, was reduced to globules of lead. 
The solution was decomposed by ammonia, which redissolved 
a part of the precipitate ; and, after edulcoration, the preci- 
pitate was dissolved by nitric acid, and precipitated again by 
ammonia, which held a less quantity in solution. The edul- 
corated precipitate was now boiled with a solution of carbonate 
of soda, which dissolved a large portion of it. The solution 
was yellowish-brown, and contained oxide of uranium. What 
was undissolved by the carbonate of soda was dissolved in sul- 
phuric acid, and seemed to be the same substance as that which 
the ammonia held in solution. A. (2.) 
The scarcity of this beautiful mineral has precluded me from 
operating on such a sufficient quantity, as a regular and rigid 
analysis required. 
The substance, which is held in solution by ammonia, has 
some peculiar properties that seem to distinguish it from ura- 
nium. And if this mineral be the Uran-glimmer, I have cer- 
tainly detected the oxide of lead, lime, and silica in it, which 
have not hitherto been considered as ingredients of that fossil. 
The green crystals differ in no respect from the yellow, except 
in containing a little of the oxide of copper. 
Creed, 
june 34th, 1805, 
