ON SUPERACID AN© SUBACID SALTS. J67 



the law under consideration : for when the circumstances are 

 such as to admit the union of a further quantity of oxalic 

 acid with potash, I found a proportion, though ditferent, yet 

 analogous to the former, regularl}' to occur. 



Quadroxalate of Potash. 



In attempting to decompose the preceding superoxalate by Quadroxalat* 

 means of acids, it appeared, that nitric or muriaiic acids are P^^^^- • 

 capable of taking only half the alkali, and th^t the salt 

 which crystallizes after solution in either of these acids has 

 accordingly exactly four times as much acid as would satu- 

 rate the alkali that remains. 



Exp. 5. For the purpose of proving, that the constitu- 

 tion of this compound has been rightly ascertained, the salt 

 thus formedshonld be purified by a second crystallization in 

 4istilled water ; after which the alkali of thirty grains must 

 be obtained by exposure to a red heat, in order to neutralise 

 the redundant acid contained in ten grams of the same salt. 

 The quantity of unburned salt contains alkali for oae part 

 out of four of the acid present, and it requires the alkali of 

 tliree equal quantities of the same salt to saturate the three 

 remaining parts of acid. 



The limit to the decomposition of superoxalate of pot- Sulphate of 



ash by the above acids is analogous to that which occurs P^^^^^^^'^f'^^ 

 " J 1 I • . aecouiposed by 



when sulphate of potash is decomposed by nitnc acio ; nitric acid. 



for in this case also, no quantity of this acid can take moie 



than half the potash, and the remaining salt is convened. 



into a definite supersulphate, similar to that obtained by heat 



in the third experiment. 



It is not improbable, that many other changes^ in chemis- Many chemi- 

 try, supposed to be influenced by a general redundance of ^^J^^^'^^^"^^ "^" 

 some one ingredient, may in fact be limited by a new order this Uw. 

 of affinities taking place at some definite proportion to be 

 expressed by a simple multiple. And though the strong 

 power of crystallizing in oxalic acid renders the modifica- 

 tions of whi<;h its combinations are susceptible more distinct 

 than those of other acids, it seems probable, that a similar 

 play of affinities will arise in solutions, when other acids ex- 

 ceed their base in the same proportion. 



In order t© determine whether oxalic acid is capable of Potash will not 



uniting 



