2 1 Dr. W. Ramsay on Picoline and its Derivatives. 



I. Taken. ..0-3247 gram. 



Silver. ..0*1825 gram, = 56*23 per cent. 

 II. Taken... 0*3590 gram. 



Silver... 0-2031 gram, = 56*57 per cent. 

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



This silver salt is not nearly so bulky as that of a-dicarbo- 

 pyridenic acid, but comes down in flocks. It is very sparingly 

 soluble in hot water, and crystallizes out on cooling in tufts 

 of microscopic needles. When heated it evolves the usual 

 smell of pyridine. It does not blacken on exposure to light. 



Methyl ether. — Prepared by cohobating the silver salt with 

 methyl iodide. It is a very deliquescent white solid, crystal- 

 lizing in needles, and soluble in water, alcohol, and ether. 



Chloride. — One gram of /3-dicarbopyridenic acid was dis- 

 tilled from a small retort along with 2*7 grams of phosphoric 

 chloride. The mixture liquefied before heat was applied. 

 The distillate was fractionated. After the oxy chloride had 

 distilled over at 110° the thermometer rose rapidly to 269-270°, 

 and remained stationary while the chloride distilled. The 

 distillate solidified to a mass of white needles, melting at 

 49°, and remaining liquid long after the ordinary temperature 

 had been regained. 



y-Dicarbopi/ridenic acid, C 7 H 5 N0 4 . — y-Dicarbopyridenic 

 acid is much more soluble then the /3-acid, and crystallizes 

 out from the mother liquor of the latter. After repeated 

 recrystallization, to free it from the /3-acid, and from a still 

 more soluble bitter substance, it was obtained in a pure 

 state. It forms tufts of spear-like crystals springing from a 

 common nucleus. When its solution in hot water is allowed 

 to cool, it crystallizes from nuclei which form on the sur- 

 face of the liquid. After being dried by exposure to air it 

 has a satin-like lustre. It is moderately soluble in water 

 at 18°; 100 cubic centimetres of its saturated solution left, 

 on evaporation to dryness, 1*1580 gram of dry acid. It is 

 easily soluble in alcohol and ether. Like its two isome- 

 rides, it decomposes when heated into pyridine and carbonic 

 anhydride about 241-245°. To ascertain if it decomposed 

 in the same manner as the /3-acid, I determined the vapour- 

 density of the mixture of pyridine and carbonic anhydride 

 yielded by the acid at the boiling-point of sulphur. To save 

 space I shall omit the details of the determination, and shall 

 merely state that the number found was 28*4, compared with 

 hydrogen. The number required by the equation 



C 7 H 5 N0 4 = C 6 H 5 N" + 2C0 2 



