JACKSON, DUNLAP. — BROMINE DERIVATIVES OF RESORCINE. 237 



determined in a specimen of the salt which had been allowed to 

 blacken and dried to a constant weight at 100°. The black body 

 is slightly hygroscopic, so it must be weighed in a weighing tube. 



0.2052 gram of the substance gave 0.0722 gram of sodic sulphate. 



Sodium 



An attempt to determine the amount of alcohol present by heating 

 some of the freshly prepared salt to 100° gave the following results : — 



0.5944 gram of the substance lost at 100° 0.1068 gram in weight. 



Calculated for 

 C 6 Br 3 H(0Na) 2 . 2 U 2 H 5 OH. Found. 



Alcohol 19.05 17.97 



This determination, although one per cent too low, is as near as we 

 could expect it to come, inasmuch as it was impossible to obtain a 

 sample for analysis which was perfectly white ; but there is a more 

 serious objection to this result and the determination of the sodium 

 in the salt dried at 100°, as we have no proof that alcohol was the 

 only substance volatilized during the decomposition and subsequent 

 drying. In fact the determinations of the amount of sodic bromide 

 contained in the dried mixture indicated that a certain quantity of 

 hydrobromic acid might have been evolved. The only analyses of the 

 salt, therefore, which are above suspicion, are those first given of the 

 white uudecomposed preparation. 



The following experiments were tried to prove the nature of this 

 decomposition of the salt. When the black decomposition product 

 was dissolved in water, and dilute sulphuric acid added, a flocculent 

 reddish brown precipitate was formed, which very much resembled 

 ferric hydrate in appearance. The clear filtrate from this gave a very 

 heavy precipitate of argentic bromide upon addition of argentic nitrate. 

 This shows that the decomposition was produced by the elimination 

 of a portion of the bromine from the ring. The amount of sodic 

 bromide formed during the reaction was determined by treating the 

 blackened salt with water of varying temperatures and for different 

 lengths of time, and then the solutions were acidified with dilute sul- 

 phuric acid, the precipitate filtered off, and bromine determinations 

 made in the clear filtrate. The results obtained were not constant, 

 varying from 32.01 per cent to 37.90 per cent of bromine, and this 

 variation may be explained by the supposition that a certain amount 

 of hydrobromic acid escaped during the decomposition. 



