and its Derivatives, 251 



Assuming the acid to be dibasic, it must contain four 

 atoms of oxygen ; and as it gave oif a smell resembling 

 pyridine Avhen heated, it contains nitrogen, probably one 

 atom. The basicity has been determined. Calculating the 

 carbon and hydrogen contained in the lead-salts, from these 

 data, to their percentage in the acid, the following are the 

 results : — 



per cent. per cent. 



Acid . . 4:(3"59 of carbon, and 3*83 of hydrogen. 

 Lead-salt 1 



calculated >46'83 of carbon, and 4*66 of hydrogen, 

 to acid. J 



The formula agreeing most closely with the above results 

 is Cg Hy NOg, which requires 45" 85 per cent, of carbon and 

 4*20 per cent, of hydrogen. Its potassium-salt would con- 

 tain 33*53 per cent, of potash; the number found by titration 

 was 33' 85 per cent. I am far from assured that the above 

 formula expresses the true composition of the new acid, and 

 should willingly have investigated it more thoroughly, had 

 not the great difficulty of separating it, and the small quan- 

 tity in which it is obtainable, rendered it improbable that 

 I should ever have procured enough for complete investiga- 

 tion. That it is distinct from dicarbopyridenic acid is suf- 

 ficiently proved by its properties. 



The silver-salt of the nev*" acid is a jelly soluble in water 

 with difficulty, and turns purple on exposure to light. Its 

 ammonium-salt volatilizes with water-vapour ; hence an 

 attempt to determine its molecular weight by evaporation 

 with ammonia was unsuccessful. The ammonium-salt gives 

 no precipitate with salts of copper, zinc, dyad mercury, 

 nickel, or tin. With salts of silver it gives a gelatinous 

 precipitate, and with ferrous salts, as already remarked, a 

 deep yellow colour. 



Oxidation of Lutidine. — Dr. Wright supposed that di- 

 carbopyridenic acid might possibly be produced by oxidation 

 of lutidine present in the picoline used; but Professor De war's 

 base, as well as that oxidized by myself, was practically free 

 from lutidine. Mr. Dewar compares the oxidation of picoline 

 to that of benzol ; the resulting bodies in both cases contain 

 more atoms of carbon than the substances from which they 

 are derived. Toluol when oxidized is much more easily con- 

 verted into benzoic acid than benzol is; but the oxidation 

 products of lutidine contain no acid precipitate with silver 

 nitrate of so low a molecular weight as dicarbopyridenic acid. 

 When lutidine was oxidized iu the same manner as picoline. 



