and ether, for which I propose the provisional name of insolinic 

 acid; purified by the ordinary processes, this body furnished on 

 analysis the following relations : 



C 9 H 4 4 ; 



but the analysis of the salts demonstrates that this formula must be 

 doubled, insolinic acid being a bibasic acid. 

 I have examined the following salts : 



Insolinic acid C 18 H 8 O 8 



Silversalt C 18 (H 6 Ag 2 ) O 8 



Copper salt C 18 (H 6 Cu 2 ) O 8 



Barium salt C 18 (H 6 Ba 2 ) O 8 



Calcium salt (at 1 00 C.) C 18 (H 6 Ca 2 ) O 8 



(at 133 C.) C 18 (H 6 Ca2) O 8 



Potassium salt (neutral) C 18 (H 6 K 2 ) O 8 



(acid) C 18 (H 7 K) 8 



Potassium-sodium salt C 18 (H 6 K Na) O 8 



When considered by itself, insolinic acid has but slight claims on 

 the attention of chemists ; but when viewed in connexion with other 

 groups of bodies, it acquires increased interest. Some years since, 

 Gerhardt pointed out that to the homologous series of monobasic 

 fatty acids C n2 H nz O 4 , the lowest terms of which are formic and 

 acetic acids, there runs parallel a homologous series of bibasic 

 acids, C n2 H n2 _ 2 O 8 , the simplest member of which is oxalic acid. 

 These two series of acids are connected by the closest ties, and very 

 conclusive experiments have demonstrated that the members of the 

 former may be easily converted into those of the latter ; such is the 

 case of the transformation of butyric into succinic acid, effected by 

 M. Dessaignes under the influence of oxidizing agents. 



The following table exhibits these two series of acids arranged 

 according to their carbon : 



Fonnic acid C 2 H 2 O 4 



Acetic acid C 4 H 4 O 4 



Propionic acid C 6 H 6 O 4 



Butyric acid C g H 8 4 



Valeric acid .'. C 10 H 10 O 4 



Caproic acid C 12 H 12 O 4 



