1824.] M. Benelius on Fluoric Acid. 333 



bility is not in the least degree augmented by an elevation of 

 temperature. At the temperature of 61°, 100 parts of water are 

 capable of retaining in solution four parts of the salt. It is 

 almost completely insoluble in alcohol. 



F/uate of Lit hi a. — a. The acid fluate is a crystallizable salt, 

 but little soluble in water, b. The neutral fluate dissolves with 

 great difficulty in water, resembling in the degree of its solubility 

 the carbonate of lithia. The solution is converted by evapora- 

 tion into a white mealy-looking mass, composed of opaque 

 granules. 



Fluate of Ammonia. — a. The acid fluate is a deliquescent salt, 

 which maybe obtained in the form of granular crystals by allow- 

 ing a solution to evaporate in a temperature about 100°. b. The 

 neutral fluate cannot be procured by the humid way otherwise 

 than dissolved in water ; because when a neutralized solution is 

 exposed to the open air, even in the ordinary temperatures, it 

 gradually loses a portion of its ammonia, and is converted into 

 the acid salt. It may, however, be easily prepared in the dry 

 way by the following process. Mix in a platinum crucible 

 1 part of sal ammoniac and 2^- parts of fluate of soda, both tho- 

 roughly pulverised, and in a state of complete dryness ; and 

 cover the crucible with an inverted lid, filled with water, in 

 order that it may be preserved sufficiently cool. Let a gentle 

 heat be now applied to the crucible by means of a spirit-lamp : 

 the fluate of ammonia will speedily volatilize without the slightest 

 admixture of sal ammoniac, and will condense upon the lid in a 

 mass of small prisms. This salt is permanent in the air : it is 

 copiously soluble in water, but only slightly so in alcohol. 

 When heated, it melts before it begins to sublime. In glass 

 vessels it cannot be preserved even when dry, without corroding 

 them. Ammonia, in the gaseous state, is rapidly absorbed by 

 it, and the product is a subsalt, which is decomposed by subli- 

 mation. 



Fluate of bari/tes is most easily obtained by digesting newly 

 precipitated carbonate of barytes in an excess of fluoric acid : 

 the carbonate is gradually converted into fluate of barytes, which 

 remains undissolved. This salt is only very slightly soluble in 

 water, or in an excess of fluoric acid. It dissolves abundantly 

 in muriatic acid, and ammonia precipitates from the solution a 

 chemical compound of fluate and muriate of barytes. The same 

 compound may be formed by mixing solutions of fluate of soda 

 and muriate of barytes. It is much more soluble in water than 

 fluate of barytes, and by evaporating the solution, may be reco- 

 vered in granular crystals. Repeated washings decompose it 

 partially ; the residue upon the filter, however, when dissolved 

 in water, retains to the last the property of precipitating nitrate 

 of silver. I found it by analysis to be anhydrous, and to be 

 composed of an atom of muriate and an atom of fluate of barytes. 



