[ 276 ] 



LI. On Super-acid arid Stib-acid Salts. By William 

 HVDE VVOLLASTON, M.D. Stc. R. S.* 



J.N the paper which has just been read to the society, Dr. 

 Thomson has remarked, that oxalic acid unites to strontlan 

 as well as to potash in two different proportions, and that 

 the quantity of acid conibined with each of these bases in 

 their super-oxalates, is just double of that which is saturated 

 by the same quantity of base in their neutral compounds. 



As I had observed the same law to prevail in various other 

 instances of super-acid and sub-acid salts, I thought it not 

 xjnlikclv that this law might obtain generally in such com- 

 pounds, and it was my design to have pursued the subject, 

 with the hope of discovering the cause to which so regular 

 a relation might be ascribed. 



But since the publication of Mr. Dalton's theory of chc- 

 Tnical combination, as explained and illustrated by Dr. 

 Thomson t, thfe inquiry which I had designed appears to be 

 superfluous, as all the facts that I had observed are but par- 

 ticular instances of the more general observation of Air. 

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

 disposed to unite atom to atom singly, or, if either is iu 

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

 nmltiple of the number of its atoms. 



However, since those who are desirous of ascertaining 

 the justness of this observation by experiment, may be de- 

 terred by the difficulties that we meet with in attempting to 

 determine with precision the constitution of gaseous bodies, 

 for the explanation of which Mr. Dalton's theory was first 

 conceived, and since some persons may imagine that the 

 results of former experiments oti such bodies do not accord 

 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 

 employed, 



* From Philosophical Transactions for 1808. 



+ Thomson's Chemistry, od edit. vol. iii. p. -325. 



Suh- 



