Mr. Connell on the Nature of Lampic Acid. 355 



so-called aldehydic acid, C 4 H 3 O 2 , 4.3; and that of aldehyde, 

 C* H 3 O + HO, 44*06. It is evident then that an acid, of 

 which a considerable part has been ascertained to be formic 

 acid, could never have an atomic weight of 50*35 by mixture, 

 either with acetic acid or with aldehydic acid ; each of these 

 of course taking up its own portion of base. The consider- 

 able mixture of formic acid would evidently keep the atomic 

 weight much below that of acetic acid ; whilst nothing short 

 of the nearly total absence both of formic and aldehydic acids 

 would give such an atomic weight as that found. But let us 

 suppose the formic acid to be mixed with acetic acid, having 

 some foreign body such as aldehyde associated with it and 

 entering into the constitution of its salts, at least on their first 

 formation ; such a mixture would readily bring up the atomic 

 weight of the mixed acid to the observed point. This becomes 

 still more evident from the experiments formerly detailed, 

 which had for their object to get quit of the associated foreign 

 matter. The lampate of barytes was kept for a considerable 

 time on the sand-bath at a temperature of from 300° F. to 

 320° F., during which operation it became dark brown, and 

 resinous matter separated when it was dissolved in water, but 

 no part of the base except a mere trace was set at liberty. The 

 atomic weight of the acid, after repeating this process twice or 

 thrice, was reduced from 50*35 to 44*95 ; and it was evident 

 that it could have been reduced still further by repetitions of 

 the process. The nature of this action I conceive to have 

 been quite analogous to that of heating aldehyde with bases. 

 It suffers decomposition and yields resinous matter. Suppo- 

 sing all the aldehyde to have been thus driven off, the acid 

 united to barytes would then have been formic acid, mixed 

 with a little acetic acid, and would have had an atomic weight 

 a little above that of formic acid. It is the most obvious, if 

 not the only mode of accounting for the considerable reduc- 

 tion of atomic weight without loss of base to suppose the ex- 

 pulsion of a foreign or associated matter. 



I am aware, as already stated, that it has been of late 

 alleged that the proportions of the constituents of lampic 

 acid vary according to the mode of preparation. This is 

 likely enough ; but then I conceive that this variation only 

 takes place in the relative proportions of formic and acetic 

 acids, and of associated aldehyde or other foreign body. The 

 greater the proportion of acetic acid and associated foreign 

 matter, the more will those appearances be observed, which 

 have led, erroneously as I conceive, to the supposition of the 

 presence of a third acid, viz. the aldehydic. It is evident that 

 no account of the properties and constitution of lampic acid 



2B2 



