380 BROMINE. 



SECTION XI. 



BROMIN 7 E. 

 Eg. 978.31 or 78.39 ; Br ; density 5393 ; [~]~|. 



This element was discovered by M. Balard of Montpellier 

 in 1826. Its name is derived from Epopee, mal-odour, and 

 was applied to it on account of its strong and disagreeable 

 odour. Like the other members of the chlorine family, it is 

 found principally in solution, being present in an exceedingly 

 minute but appreciable proportion in sea water, under the form 

 of bromide of sodium or magnesium, also in the water of the 

 Dead Sea, and in nearly all the saline springs of Europe, of 

 which that of Theodorshall near Kreuznach in Germany is the 

 principal source of bromine, as an article of commerce. Although 

 it has not been found applicable to any important purpose 

 of utility, bromine is interesting from its chemical relations, 

 particularly from the extraordinary parallelism in properties with 

 chlorine which it exhibits. 



Preparation. Bromine in combination is detected by means 

 of chlorine water, a few drops of which cause the colourless so- 

 lution of a bromide to become orange yellow, like nitrous acid, 

 by disengaging bromine, while an excess of chlorine weakens 

 the indication, by forming a chloride of bromine which is nearly 

 colourless. Before the application of this test, the saline water 

 in which bromine is contained must always be greatly concen- 

 trated, and, indeed, the greater part of its salts separated by 

 crystallization. The bromides are highly soluble and remain 

 in the incrystallizable liquor which is called the mother-ley, or 

 bittern in the case of sea-water. The bromide of magnesium 

 may lose hydrobromic acid during the farther concentration of 

 the mother-ley, by evaporation, on which account Desfosses re- 

 commends the addition of hydrate of lime to the liquid, which 

 throws down magnesia, and produces a bromide of calcium 

 which may be evaporated without loss of bromine. Instead of 

 using free chlorine, to extricate the bromine, peroxide of man- 

 ganese and a little hydrochloric acid may be added to the li- 

 quid. Upon distilling, bromine is liberated and comes off com- 

 pletely before the liquid boils. The watery vapour which 

 condenses in the receiver along with the bromine, contains a 



