Mr. Connell on the Nature of Lampic Acid. 513 



last edition of his valuable treatise on chemistry, has adopted 

 without comment this view of M. Liebig as to the identity of 

 the properties of these two acids*. 



The object of my inquiry is not aldehydic acid. The che- 

 mical world will gladly receive further light respecting that 

 acid ; but I think it will not be difficult to show that it will not 

 be safe in the mean time to receive lampic acid as its repre- 

 sentative. 



It would appear that M. Liebig did not make any experi- 

 ments himself on lampic acid. He however drew from the 

 experiments of Messrs. Daniellf and Phillips the following 

 conclusions, which led him to suppose the identity of the 

 two acids, and which it will be observed differ in several par- 

 ticulars from those which these able chemists had themselves 

 drawn. 



" 1st. Lampic acid reduces the salts of mercury and silver 

 without effervescence. 



" 2nd. During this reaction it is changed into acetic acid. 



" 3rd. Its atomic weight is the same, or very nearly the 

 same, as that of acetic acid." 



These conclusions shall be examined in their order, after 

 describing the mode of preparation of the acid liquid. 



The acid examined in my former researches on this subject 

 was prepared by suspending a small piece of ignited spongy 

 platinum by a fine platinum wire, over aether covered by a 

 glass funnel, to condense the vapours formed. In the present 

 case I substituted a coil of fine platinum wire for the piece of 

 spongy platinum, but no difference was observed in the qua- 

 lities of the acid obtained. The sulphuric aether was con- 

 tained in a small evaporating basin which was placed in a 

 large one. The coil of fine platinum wire was then suspended 

 by a long wire of the same kind in a large inverted glass 

 funnel ; and after the coil had been ignited the funnel was 

 placed in the larger evaporating basin so as to bring the coil 

 a little way above the surface of the aether. An alembic was 

 then suspended a little way above the narrow extremity of the 

 funnel ; and the acid vapour formed was condensed princi- 

 pally in the funnel, from which it fell back into the large eva- 

 porating basin, and partly in the alembic head|. The small 



* Lehrbuck, i. 159. 3te Auf. 



t [The principal results originally obtained by Mr. Daniell were stated 

 in Phil. Mag., First Series, vol. liii. p. 64.— Edit.] 



I When the funnel is large, as from five to six inches' diameter, it should 

 not be raised, so long as the operation continues, because an explosion is 

 apt to ensue from the too great access of air, although without injury to 

 the vessels. On the other hand, when it is smaller it is necessary to place 

 some thin fragments of glass below its edge, to admit air. 



Third Series. Vol.11. No. 70. Dec. 1837. 3 U 



