272 Dr. \Y. Ramsay on Picoline and its Derivatives* 



hydrochloride appears to absorb chlorine when a current of 

 that gas is passed over it, but evolves the chlorine on exposure 

 to air. No apparent change is produced even when the hydro- 

 chloride is strongly heated during its treatment with chlorine. 

 Action of Bromine on Picoline Hydrobromide. — The result 

 of treating the hydrobromide with bromine is different. When 

 bromine is added to a solution of the hydrobromide in water, 

 a mass of needles is formed almost instantaneously. The reac- 

 tion takes place easily if a strong solution of picoline hydro- 

 bromide be heated with bromine in a sealed tube to 190° for 

 an hour. The yellowish-red oil which at first sinks to the 

 bottom, dissolves in the water ; and on cooling, the fluid is filled 

 with beautiful golden scales, while a reddish-yellow crystalline 

 mass remains at the bottom of the tube, consisting of excess of the 

 compound with bromine which the water was not able to dis- 

 solve. The scales, after being collected and dried over sul- 

 phuric acid, had a distinct smell of bromine. On analysis the 

 following numbers were obtained : — 



I. 0*3015 grm. of substance gave 0*5043 grm. of AgBr = 

 71*17 per cent, bromine. 



II. 0*3683 grm. of substance gave 0*5725 grm. of AgBr, 

 and 0*0088 grm. of Ag, together equal to 68*04 per cent, 

 bromine. 



The former analysis was performed with freshly prepared 

 material ; while the substance analyzed giving the results of 

 No. II. had stood over sulphuric acid for some days, and had 

 evidently lost bromine. The result of No. I. agrees suffici- 

 ently well with the formula C 6 H 7 N . Br 2 . HBr, which demands 

 71*85 per cent, of bromine. 



When the dibromide of picoline hydrobromide is heated with 

 water in an open vessel, bromine is evolved ; and it is possible 

 thus to remove the two additive atoms of bromine, leaving pure 

 picoline hydrobromide. It is sparingly soluble in water ; and 

 if soda or potash is added to its aqueous solution, picoline is 

 liberated ; if the alkaline liquid is acidified, the bromine com- 

 pound appears to be again formed. It melts at about 85°; 

 but as it evolves bromine when warmed, the exact point is not 

 easily determined. 



Bromine does not act substitutingly on picoline hydrobro- 

 mide ; for even after heating the two together for a week to 

 1 80°, no hydrobromic acid was evolved, although a black tarry 

 mass was formed. 



Nicotine forms a similar additive compound with bromine ; 

 and this constitutes an additional proof that there is some con- 

 nexion between the two bases, nicotine and picoline or pyridine. 



Action of Iodine on Picoline Hydriodide. — When picoline 



