ON FLUOR 45 



wonderfully altered acids, it must be thrown down by the 

 volatile ley. 



SECTION VII. 



To set the matter in a still clearer light, I used a 

 different species. Some yellow cubical fluor from Saxony 

 being heated and pounded, and then distilled in the iron 

 tube, with a double quantity of oil of vitriol, and with 1 drm. 

 of water in the leaden receiver, yielded a thin pellicle, of the 

 appearance of lead, but no siliceous crust. By precipitation 

 with volatile alkali I got 2J grs. of grey earth. 



1 drm. mixed with the same quantity of pulverised sand 

 afforded a pellicle of lead, interspersed with a few particles 

 of white crust, which ran into glass under the blowpipe. 

 Volatile alkali precipitated 8 grs., a striking difference. 



1 drm. mixed with an equal quantity of green glass 

 reduced to powder, swelled a good deal, and yielded a thick 

 siliceous crust. 



SECTION VIII. 



Not yet satisfied with these experiments, I added to 1 dr. 

 of green fluor, that had been heated and pounded, 2 drms. of 

 oil of vitriol, still employing the iron tube. I also suspended 

 a piece of wet charcoal in the inside, fixed a cover upon the 

 tube, heated it in a sand-bath, and found, upon taking off 

 the cover, in the space of fifteen minutes, that the charcoal 

 was dry, and had no earth upon it. I now added a scruple 

 of sand in fine powder, wetted the charcoal, and replaced it ; 

 but found after the same time nothing more than at first. 



Some bits of green glass were now thrown into the mixture, 

 when it began to foam so vehemently, that it ran over ; and 

 I did not now hang the charcoal in the tube, as it was no 



