OF AUTS AiND SCIENCES. 249 



The results of these three experiments, calculated into percentages 

 of the side-chain bromine, are given lor the sake of comparison in the 

 following table : — 



Owing to the different conditions under which they were made 

 these series of experiments are not comparable with each other, or 

 with the series given in Tables I. and II., even I. not having been 

 made under exactly the same conditions ; they show, however, that 

 there is no limit to the reaction in the case of the parabrombenzylbro- 

 mide and probably none in the case of any of these substances. 



Action of Water on the Monohrombenzylbromides. 



Another entirely different method was also tried, which consisted in 

 heating the substituted benzylbromides with water in sealed tubes, and 

 determining the amount of hydrobromic acid formed by the reaction, — • 



CgH.BrCH^Br + Hp = CgH^BrCH^OH + HBr 



For this purpose one gramme of each substance was weighed in a 

 tube about 14 cm. long and 2 cm. wide; 5 c.c. of water were added, 

 and, after sealing, the tubes were put into a hot chloride of calcium 

 bath, provided with an air-tight tin cover carrying a return-cooler, 

 which thus was kept at a constant temperature throughout the process. 

 After a definite time the tubes were removed, cooled as rapidly as 

 possible with cold water, and the contents washed into a beaker, and 

 titrated with a standard solution of baric hydrate. The following ex- 

 periments were made with two portions of parabrombenzylbromide to 

 test the process. 



