ON FLUOR 47 



SECTION X. 



To a mixture of half an ounce of fluor, and the same 

 quantity of glass in powder, 1J oz. of oil of vitriol being 

 added in a retort that was thus half filled, the in- 

 gredients acted so violently on each other, that in a short 

 time the mixture rose to the neck of the retort. It was left 

 exposed to the open air on account of the vapour, and the 

 next day I found the rim of the retort covered with 

 fasciculated crystals as with hoar-frost. 



The same mixture being on another occasion made in a 

 capacious retort, and thoroughly blended by agitation, became 

 a thick mass, and swelled like dough in fermentation ; the 

 bottom of the retort grew very hot, and the siliceous crust 

 appeared on 3 oz. of water which had been put into the 

 receiver. 



At the end of the distillation, which was continued three 

 hours, I found 16 grs. of siliceous earth on the surface of 

 the water, and the precipitate by volatile alkali weighed 56 

 grs. The retort was not nearly so much corroded as usual. 



On distilling 30 grs. of this precipitate in a glass retort 

 with 1 J drm. of oil of vitriol, I saw no siliceous earth on the 

 water in the receiver, nor sublimate, nor did spirit of sal 

 ammoniac throw down anything, either out of the water in 

 the receiver, or that with which the earth was edulcorated. 

 I mixed the ley of fluorated volatile alkali with a solution of 

 chalk in nitrous acid, till no more precipitation took place. 

 The mixture was passed through nitrous acid, and the 

 precipitate edulcorated ; it weighed, when dry, 2 drms. 

 36 grs. 



2 drms. of oil of vitriol being added to 1 drm. of this 

 precipitate contained in a glass retort, the precipitate was 



