514* Mr. Connell on the Nature o/Lampic Acid. 



quantity of residual liquid in the smaller evaporating basin 

 was always thrown away as not consisting of condensed va- 

 pour. From 2 ounces of aether, which required about 2 J 

 hours for consumption, rather more than a dram of the con- 

 centrated acid liquid was usually obtained, and the vessels 

 were washed out with another dram of distilled water, which 

 was added to the acid liquid, in whic> state it was employed 

 in the experiments detailed. 



It is unnecessary to say that the liquid thus obtained pos- 

 sesses powerful acid qualities, reddening vegetable colours 

 strongly and effervescing briskly with carbonates : and when 

 we talk of the nature of lampic acid, my understanding of 

 the expression is that we thereby mean the nature of the acid 

 thus contained ready formed in the liquid so procured. That 

 there are other products of an ethereal, oily, or resinous de- 

 scription contained in the liquid there is no doubt ; but these 

 are not acids ; and it will be unnecessary to have recourse to 

 the supposition that they produce or modify the reactions of 

 the acid which they accompany, if it can be shown that that 

 acid exerts in its own nature all the characteristic reactions 

 of the liquid. The examination of these accompanying pro- 

 ducts did not come within the scope of my inquiry either at 

 present or formerly. 



I. To determine experimentally whether lampic acid re- 

 duces the salts of silver and mercury without effervescence, a 

 little of the acid was placed in a tube with solution of proto- 

 nitrate of mercury, whilst one end of a narrower tube was fitted 

 into the larger by means of a cork, and the other extremity 

 terminated in a small quantity of lime-water. On applying 

 heat to the mixture there was brisk effervescence, precipita- 

 tion of metallic mercury, and evolution of elastic fluid which 

 speedily made the lime-water very muddy; and on adding 

 an acid to the lime-water the muddiness disappeared with ef- 

 fervescence. 



This experiment was repeated, substituting peroxide of 

 mercury for the protonitrate. Copious effervescence ensued 

 as before, and evolution of elastic fluid which made the lime- 

 water muddy; and there was at first on partial cooling a pre- 

 cipitation of white saline matter, and on the further applica- 

 tion of heat this disappeared with precipitation of metallic 

 mercury. 



When solution of nitrate of silver was heated with lampic 

 acid until effervescence and precipitation of metallic silver as 

 a dark brown powder ensued, and the action was maintained 

 by the occasional application of heat, the lime-water into which 

 the evolved gas was conducted became very muddy as before. 



