ON SUPERACID AND SUBACID SALTS. ] g^ 



superfluous, as all the facts that I had observed nre hut par- j 



tlcular instances of the more general observation of Mr. ; 



Dalton, that in all cases the simple elements of bodies are > 

 disposed to \inite atom to atom singl}', or, if either is in ex- 

 cess, it exceeds by a ratio to be expressed by some simple 



multiple of the number of its atoms. ; 

 However, since those who are desirous of ascertaining the A few easy ex- ; 



iustness of this observation by experiment may be deterred pe"ments tend j 



,,,.„,., •' }, . -. , to veufj this. f 



by the difficulties, that we meet with in attempting to deter- t 



mine with precision the constitution of gaseous bodies, for . 



the explanation of which Mr. Dalton's theory was first con- i 



ceived; and since some persons may imagine, that the re- '' 



suits of former experiments on such bodies do not accord -i 



sufficiently to authorize the adoption of a new hypothesis, \ 



it may be worth while to describe a few experiments, each < 



of which may be performed with the utmost facility, and '] 



each of which affords the most direct proof of the propor- ] 



tional redundance or deficiency of acid in the several salts j 



employed. . 



Subcarbonate of Potash. I 



Exp. 1. Subcarbonate of potash recently prepared, Is Subcarbonate ' 



one instance of an alkali having one half the quantity of ^^P^'^*^^* ' 



acid necessary for its saturation, as may thus be satisfacto- ' 



rily proved. j 



Let two grains of fully saturated and well crystallized car- 

 bonate of potash be wrapped in a piece of thin paper, and j 

 passed up into an inverted tube filled with mercury, and let 

 the gas be extricated from it by a sufficient quantity of mu- ■ 

 riatic acid, so that the space it occupies may be marked upon \ 

 the tube, ; 

 Next, let four grains of the same carbonate be exposed for • 

 a short time to a red heat ; and it will be found to have part- 

 ed with exactly half its gas; forthe gas extricated from it in 

 the same apparatus will be found to occupy exactly the same 

 space, as the quantity before obtained from two grains of \ 

 fully saturated carbonate. ^ j 



Subcarbonate of Soda. \ 



Exp' 2. A aiuular experiment may be made with a satu- Subcarbor^rc I 



rated °^ ^'^^*' \ 



