352 



QUANTITY OF WATER IN FUSED SODA. 



and the same is As to tlic water carried off by the gas, when the cxperi" 

 true of these- niciit is performed with due caution in proper vessels, the 

 gas only carries with it hygrometrical water. Now this 

 quantity may easily be calculated. The gas in my experi- 

 ment weighed 4*195 gram. [64*77 grs.] : consequently its 

 volume, at 20® [eS^-F.] and 0-75 met. [29*5 in.] pressure, 

 was 2-3 lit. [48 pints] ; and the weight of the aqueous 

 vapour =4*2 cent. [0*65 of a gr.^. If this quantity be 

 diminished by the very small quantify of carbonic acid rc- 



erroiir, to which this analysis is liable ; for the process is 

 so simple, that on repeating it we obtain almost precisely 

 the same quantities. I conceive it much to be wished, that 

 all analyses were susceptible of this precision : besides, I 

 have confirmed it by other experiments. I reduced the sub- 

 carbonate to muriate and sulphate, and the results I ob- 

 tained Avere found to agree with the analysis I had adopted. 



I now proceed to the objections which Mr. d'Arcet has 

 made to my method of determining the water in soda, and 

 which consist in this, that the component parts of muriate 

 of silver are not accurately determined; and that this salt is 

 soluble in the waters of elutriation. 



Chcnevix, Zaboade, Proust, Bucholz, Rose, and others, 

 have successively determined the proportions of muriate of 

 silver. The quantity of acid contained in this salt varies 

 in their results from 17 to 18. Rose and Bucholz make it 

 17*5, which is the proportion I have adopted. The late 

 experiments of Gay-Lnssac carry it to 18. When the 

 proportions assigned to a salt vary only half a hundredth 

 part, they m.^.y be fairly considered as ascertained. 



With regard to the solubility of muriate of silver, I 



fil^SielS?' believe we may affirm, that it is one of the most insoluble 



salts employed in analysis, when the liquid is neutral and 



contains very little of any other salt. It even requires a 



pretty considerable excess of acid, to dissolve any notable 



Objections to 

 the mode of 

 determining 

 the water in 

 soda. 



Proportions of 

 muriate of sil- 

 ver ascertained 



This muriate is 



* There is slill another circumstance, that tends to diminish the 

 weight of the carbonic acid : this is, the gas evolved expels great 

 part of the atmospheric air contained hi tjie empty part, and takes 

 its place. 



quantity 



