16 ESSAY I. 



(e) On the addition of lime-water, regenerated fiuor was 

 instantly precipitated. 



(d) A precipitate of the same nature as the former was 

 obtained, when the compound of fluor acid and volatile alkali 

 was put into a solution of muriated lime. The liquor was a 

 solution of common sal ammoniac. 



(e) Regenerated fluor was likewise precipitated by a 

 solution of lime in nitrous acid. 



(/) A powder was precipitated from the solution of silver, 

 which, by means of the blowpipe, was reduced to silver, 

 losing at the same time its acid, which partly flew off, and 

 in part united with the watery particles of the flame, 

 generated siliceous earth, which appeared in the form of a 

 white circular spot upon the charcoal, round the reduced 

 silver. 



(g) A mass was precipitated from the solution of quick- 

 silver in nitrous acid, entirely volatile in heat ; but a solution 

 of corrosive sublimate remained unchanged. 



(h) All the lead was precipitated from its solution in 

 nitrous acid. 



(i) A solution of vitriolated magnesia became turbid. 



(k) Vitriolic acid, mixed with the solution of this kind of 

 sal ammoniac, and distilled in close vessels, yielded pure fluor 

 acid, which formed at the same time a thick crust upon the 

 water in the receiver. 



Regenerated fluor, obtained in the manner as mentioned 

 (c), (d), (e), is decomposed by digestion with aerated vegetable 

 alkali. The acid of fluor unites with the alkali; but the 

 calcareous earth, thus freed, uniting at the same time with 

 the aerial acid, falls to the bottom of the vessel. 



When the experiment was made with aerated volatile 

 alkali, no decomposition ensued. 



