Mr. Connell on the Nature of Lampic Acid. 519 



It was then digested in alcohol for some time under the idea 

 that more of the resinous matter would be taken up ; but as 

 the alcohol had dissolved a little of the salt itself and had not 

 acquired a deep tint, it was evaporated to dryness and the re- 

 sidue returned to the original mass of the salt. The whole 

 was again dissolved in water, filtered from a fresh quantity of 

 resinous matter which separated on the application of heat, 

 and finally evaporated to dryness. The salt thus obtained, 

 and which still had a brown colour, was dried in vacuo over 

 sulphuric acid: 12-34- grains of it thus dried yielded 11*78 

 grains of sulphate of barytes, which would give the consti- 

 tuents of the salt as 



Acid 4-609 37*36 



Barytes 7*731 62*64« 



12*34.0 100* 



and the atomic weight of lampic acid as 570*7. Thus by the 

 separation of these successive portions of resinous matter the 

 apparent atomic weight of the acid had been reduced from 

 629*4- to 570*7 ; but it was evident that the salt still contained 

 impurity both from its own brown colour and from that of the 

 solution separated from the sulphate of barytes in the analysis ; 

 and it would have required a frequent repetition of the pro- 

 cess to have approached the true combining proportion of the 

 acid. This, however, the circumstances did not require 

 should be done, it being sufficient to show that the atomic 

 weight was not the same, nor nearly the same, as that of acetic 

 acid; for little doubt could then remain that the real combi- 

 ning proportion was that which belongs to the mixture of 

 known acids of which it is conceived that lampic acid has 

 been ascertained, by its ordinary reactions, to consist. 



Care was taken to establish that the treatment had not 

 altered the nature of the barytic salt analysed. The soda salt 

 obtained in the latter analysis, and containing the acid which 

 had been previously combined with barytes, still reduced 

 protonitrate of mercury with effervescence and evolution of 

 carbonic acid on the application of heat ; and by an examina- 

 tion of the resinous matter which had separated, it was ascer- 

 tained-that not more than T |^ of the barytes contained in the 

 salt examined had been separated during the treatment to which 

 it had been subjected, so that only a very minute quantity of 

 the salt had been decomposed, if indeed the trace of barytes 

 separated had not previously been combined with the impurity 

 itself. 



The conclusions to which all my experiments have led are 

 the following : 



