«;6o On some PrcfpeH'm of the Pkoipkoric Acid 



^fetallic favour, and tinged the skin black ; but the latter 

 property does not belong to phosphate of silver. 



By rest a considerable quantity of nitrate of silver still 

 crystallized, but the metallic savour was not yet entirely 

 lost. 



More cr)^stals continued to appear by spontaneous eva- 

 poration, in conseiquence of which the metallic savovir be- 

 came still less perceptible : but as the crystals possessed all 

 the properties of nitrate of silver, I considered all further 

 examination of the supernatant acid as superfluous, as it 

 could be nothing else than phosphoric acid. 



III. A dmilt similar to that in regard to the qitestioTtf 

 JVhetlter solution of silver is decomposed P arises in regard 

 to that, IVhetfier a solution ofviuriate of harytes gives a 

 precipitate by mixture with phosphoric acid P 



Morveau poured phosphoric acid into a solution of mu- 

 riate of barytes, and obtained a precipitate of phosphate of 

 barytes*. 



Grent found it confirmed, by his own experiments, that 

 the phosphoric acid decomposes muriate of barytes by sim- 

 ple affinity. 



As phosphate of barytes is so easily dissolved by free acid, 

 I was of opinion that this assertion of that chemist, how- 

 ever respectable, \Vas not to be admitted without further 

 examination. 



To ascertain the truth of my conjectures, t dissolved in 

 distilled water two gros of perfectly pure muriate of barytes; 

 and having mixed it with one gros of concentrated phos- 

 phoric acid which had been before somewhat diluted in di- 

 stilled water, no trace of precipitate appeared. 



A repetition of this experiment several times with the- 

 same and larger quantities of these substances, confirmed 

 the observation, that no precipitate is formed by a mixture 

 of pure phosphoric acid with a solution of pure muriate of 

 barytes. 



As in ever)' case when a very small quantity of phospho- 

 ric acid was dropped, a very perceptible taste of this acid 

 was observed, this phaenomenon seemed to show that ho 

 decomposition of the muriate of barytes had taken place. 



To ascertain this, however, beyond a doubt, I mixed the 

 solution of two gros of muriate of barytes with one gros of 



* Morveau ut supri; and Macquer's Chem. Diet, part iv. 

 f Handbuch dei Ciicmie, vol. ii. p. 300. 



phosphoric 



