5 1 8 Mr. Connell oil the Nature of Lampic Acid. 



it been entirely acetate of mercury, the acid obtained from it 

 would simply have dissolved the peroxide of mercury. 



From all these considerations it is manifest that there are 

 no grounds for supposing that lampic acid when it reduces 

 the salts of silver or mercury is converted into acetic acid. 



III. The last point relates to the atomic weight of this 

 acid. 



The observations which follow on this subject will, perhaps, 

 appear to be superfluous to those who may be of opinion that 

 lampic acid has been shown by sufficiently decisive charac- 

 ters to consist of known acids. The apparent puzzle on this 

 point has arisen from the foreign substances contained in the 

 acid liquid disguising the result obtained, as will be suffi- 

 ciently evident from what follows. I made an analysis of 

 lampate of barytes, and at first obtained a result identical with 

 that of Professor Daniell. The salt was prepared by satura- 

 ting lampic acid with carbonate of barytes, and was once or 

 twice alternately dissolved in water and evaporated to dryness. 

 At each successive evaporation it emitted pungent vapours, 

 and continued a brownish and partially crystallized mass. It 

 was then reduced to powder and dried in vacuo over sulphuric 

 acid. 6*8 grains of the salt thus prepared were dissolved in 

 water and precipitated by sulphate of soda. The sulphate 

 of barytes after ignition weighed 6*25 grains, equivalent to 

 4*1017 of barytes. These data would give as the constituents 

 of the salt 



Acid 2-6983 39*68 



Barytes ... 4-1017 60*32 



6-8 100* 



and 629*4 as the atomic weight of lampic acid, that of acetic 

 acid being 643*19 and that of formic acid 465*35; but the 

 brown aspect of the salt was quite sufficient to show that it 

 was not in a state of purity ; the impurity of course having 

 the effect of increasing the apparent atomic weight of the 

 acid. Accordingly it was easy to separate from it a quantity 

 of brown resinous matter without altering its nature. A 

 quantity of the salt was kept on the sand-bath at the tempera- 

 ture of from 300° Fahr. to 320° Fahr. for three quarters of 

 an hour. By this treatment it became dark brown, and on 

 solution in water when cold, much dark brown resinous mat- 

 ter was deposited. The solution separated from this matter 

 was still coloured and was evaporated to dryness, and the 

 mass again kept at a similar temperature for several hours. 

 When again dissolved in water, more resinous matter sepa- 

 rated, and when again evaporated the mass was still brown. 



