BROMINE. 381 



portion of chloride of bromine, from which the bromine may 

 be separated by adding barytes to the liquid, and forming a 

 chloride of barium and bromate of barytes ; evaporating the li- 

 quor to dryness, and treating with alcohol. 



Properties. Bromine condenses in the preceding process as 

 a dense liquid under the water, the sp. gr. of bromine being 

 2.9G6. In mass, it is opaque and of a dark brown red, but in a 

 thin stratum, transparent and of a hyacinth red. Its odour is 

 powerful and very like that of chlorine. When cooled 10 

 or 15 degrees below zero, it freezes, and remains solid at 10; 

 it then has a leaden gray colour and a lustre almost metallic. 

 Bromine at the usual temperature is decidedly volatile, and to 

 retard its evaporation, it is generally covered by water in the 

 bottle in which it is kept. It boils at 116. 5, and affords a va- 

 pour very similar to the ruddy fumes of peroxide of nitrogen. 

 Bromine is soluble to a small extent in water, and gives an 

 orange coloured solution ; it is a little more soluble in alcohol, 

 and considerably more so in ether. 



Bromine bleaches like chlorine, and acts in a similar manner 

 upon the volatile oils and many organic substances containing 

 hydrogen, which element it eliminates in the form of hydro- 

 bromic acid. Many metals combine with bromine with ignition, 

 as they do with chlorine ; it acts as a caustic on the skin and 

 stains it yellow, like nitric acid. It forms a combination with 

 starch, which is of a yellow colour ; like chlorine it forms a 

 crystalline hydrate with water at 32, which is of a beautiful red 

 tint. 



Hydrobromic acid, H Br. This is a gas, in which 2 volumes 

 of each constituent are united without condensation, as in hy- 

 drochloric acid, and which has the great attraction for water of 

 that acid. Hydrogen and bromine do not unite at the usual 

 temperature, and a mixture of them is not exploded by flame, 

 but they unite in contact with the flame and form hydrobromic 

 acid. The same acid is more readily prepared by the action of 

 bromine upon certain compounds of hydrogen, such as sul- 

 phuretted hydrogen, phosphuretted hydrogen and hydriodic 

 acid. The gas may also be obtained by the mutual action of 

 bromine, phosphorus and water, and must be collected over 

 mercury. 



Hydrobromic acid, like all the other bromides, is decomposed 

 by chlorine, which is more powerful in its affinities than bro- 



