26 Dr. W. Ramsay on Piooline and its Derivatives. 



hot solution of tho ammonium salt. On cooling, small plates 

 crystallized out. After being dried over sulphuric acid it was 

 analyzed. 



Taken 0-2530 gram. 



Loss at 150°... 0-0310 gram, = 12-25 per cent. H 2 O. 

 The residue, after conversion into Ca C0 3 , weighed 0*1116 

 gram,=20 , ll per cent. Ca in the dried acid. C 7 H 3 N0 4 Ca 

 2H 3 contains 14*93 per cent. H 2 O ; and C 7 H 3 N(\Ca, 

 19*51 per cent. Ca. 



Silver salt. — The silver salt comes down on addition of 

 silver nitrate to a solution of the acid as a flocculent preci- 

 pitate, closely resembling that of the |3-acid, but not nearly 

 so gelatinous or bulky as that of the g-acid. It is very 

 sparingly soluble in water. 



I. Prepared by adding silver nitrate to the acid. 



Taken... 0*4475 gram. 



Ag 0*2465 gram, = 55*08 per cent. 



II. and III. Prepared by adding silver nitrate to the 

 ammonium salt. 



Taken... 0*2967 gram. 



Ag 0*1673 gram, = 56*38 per cent. 



Taken... 0*2305 gram. 



Ag 0*1305 gram, = 56*61 per cent. 



C 7 H 3 N0 4 Ag 2 contains 56*69 per cent, of silver. 



ry-Dicarbopyridenyl chloride. — The chloride was prepared in 

 the usual manner; it boiled at 265°. On exposure to air it 

 turns bluish-violet, and liquefies. It solidifies with great re- 

 luctance at the ordinary temperature ; and yet its melting- 

 point is at 88-89°. It appears to be much more easily decom- 

 posed by water than the chlorides of the a- and /3-acids, for it 

 turns liquid at once on treatment with cold water. 



Bitter substance. — The bitter substance already mentioned 

 remained in the mother-liquor of the /3- and 7-dicarbopyridenic 

 acids. It was partially separated by adding lead or silver 

 nitrates to a neutral solution ; for both these salts are soluble 

 in acid. The lead salt, when decomposed by sulphuretted 

 hydrogen, gave a solution which was evaporated to a syrup. 

 The bitter substance does not crystallize from water or alcohol ; 

 it is extremely soluble in both these solvents, but less easily 

 soluble in ether. It is an acid; its barium salt is a syrup, 

 which dries up to a vitreous mass over sulphuric acid. The 

 acid, as well as its salts, give off the usual smell of pyridine 

 when heated, and also give a red coloration with ferrous 

 sulphate. It was unfortunately lost, after it had been separated 

 in a nearly pure state. 



