Dr. W. Ramsay on Picoline and its Derivatives. 25 



is 27*8. The equation is thus proved to represent what 

 happens when 7-dicarbopyridenic acid is decomposed by 

 heat. 



7-Dicarbopyridenic acid gave the following numbers on 

 analysis : — 



I. Taken 0*3075 gram. 



Loss at 100°, 0*0475 gram, = 15*44 per cent. H 2 O. 

 The remainder , 0*2600 gram, on combustion gave 



C0 2 0-4929 gram, = 51-70 per cent. C. 



H 2 0-0740 gram,= 3-16 per cent. H. 



II. Taken 0*3582 per cent, of dry acid. 



C0 2 0-6697 gram, = 50-98 per cent. C. 



H 2 0*0974 gram, = 3-02 per cent. H. 



III. When dried for one night over sulphuric acid, 



0-3085 gram of the acid lost at 100° 0*0380 gram, 

 = 12-31 percent, of H 2 O. 



IV. After being dried for a long time in air, 0*2290 gram 



lost at 100° 0*0235 gram,= 10*26 per cent, H 2 O. 



C 7 H 5 N0 4 contains 50*30 per cent. C. and 3*00 per cent. H. 

 C 7 H 5 N0 4 . H 2 O contains 9*73 per cent. H 2 O ; with lfE 3 O, 

 13*91 per cent,; and with 2 H 2 O, 17*78 per cent, 



The acid, wdien dried in air, appears to contain less than 

 two molecules of water, and when dried over sulphuric acid, 

 more than one molecule. 



Reactions of y-Dicarhopyridenic acid. — A cold saturated 

 solution of the acid gave no precipitate with the following 

 salts : — Ca Cl 2 , even after addition of ammonia ; Ba Cl 2 , 

 MgS0 4 , Zn S0 4 , Cd Cl 2 , Hg Cl 2 , Ni (N0 3 ) 2 , Co(N0 3 ) 2 . Ferric 

 chloride causes a white flocculent precipitate, soluble in 

 hydrochloric acid, and converted into ferric hydrate by am- 

 monia ; mercurous nitrate gives a bulky white precipitate ; 

 stannous chloride, a flocculent precipitate ; copper sulphate, a 

 whitish blue precipitate ; lead nitrate, a white precipitate, 

 which disappears at first, probably owing to formation of an 

 acid salt, but on addition of more lead salt it becomes perma- 

 nent ; silver nitrate gives a white flocculent precipitate , 

 slightly soluble in hot water. Ferrous sulphate gives a blood- 

 red coloration. 



Salts of <y-Dicarbopyridenic acid. 

 Ammonium salt. — White needles. 



0*2708 gram of acid gained 0*0575 gram when evaporated 

 with ammonia, = 17*37 per cent, NH 3 . 



Calculated for C 7 H 3 N0 4 (NH 4 ) 2 , 16*91 per cent. 

 Calcium salt. — Prepared by adding calcium chloride to a 



