JACKSON AND DERBY. — FERROUS IODIDE. 225 



NH 4 BrIBr. The product had a reddish brown color, aud gave off bro- 

 mine when exposed to the air. It was investigated by treating it with 

 ether, in which a portion dissolved with considerable evolution of heat. 

 The residue insoluble in ether had a yellowish color, and seemed to be a 

 mixture of ferric bromide and amnionic bromide in varying proportions. 

 These two substances were recognized by the usual tests. The ether 

 extract on evaporation left a residue which was green with a brilliant 

 metallic lustre by reflected light, deep blood red by transmitted light ; it 

 resembled rosauiline, therefore, but the red color was less purplish than 

 in that body. Examined with the microscope, crystals which looked like 

 amnionic bromide were observed. It had a strong odor similar to that 

 of bromide of iodine, and, although not really stable, could be kept for 

 some time without much decomposition. Upon treating it again with 

 ether a fresh quantity of the insoluble yellowish residue was left behind. 

 The residue obtained by evaporating one of our first ether extracts was 

 analyzed with the following results : 



0.7149 gram of the substance gave 0.0216 gram of ferric oxide, 0.0405 

 gram of ammonia, 1.4289 grams of mixed silver salts which yielded 

 0.7G52 gram of silver. 



In calculating these results, as the iron from its small amount was 

 evidently an impurity, the amouut of ferric bromide corresponding to it 

 has been subtracted from the amount of substance taken, and the bromine 

 contained in this ferric bromide from the bromine found. As the sub- 

 stance gave a test for a ferrous salt, it would have perhaps been more 

 correct to consider the iron present as ferroferric bromide, and this would 

 have given numbers agreeing better with those calculated from the form- 

 ula; but we think it wiser to give the results on the assumption that ferric 

 bromide was present, as we cannot believe that the amount of ferrous 

 bromide was more than a trace, since the substance had been exposed to 

 an excess of bromine. 



Calculated for NH 4 BrIBr. Found* 



Ammonium 5.90 6.38 



Iodine 41.64 40.96 



Bromine 52.46 53.32 



These numbers would seem conclusive if it were not for the presence 

 of the small amount of ferric bromide (considered in calculating them) 



* If tlie ferric bromide was not subtracted, the numbers were, NH 4 5.67, iodine 

 36.39, bromine 56.41. 



VOL. XXXV. — 15 



