BROMINE, a non-metallie element. Symbol Br; atomic weight, 79.4. Bro mine was discovered in 1826 by Balard, in the salts obtained by the evaporation of sea water. Bromine is liberated from the sodium and magnesium salts by the action of free chlorine, and is separated by ether, which dissolves the bromine. This red-colored solution is removed, saturated with potash, evaporated, and heated to redness, and the bromide of potassium is heated with manganese dioxide and sulphuric acid. The bro mine is liberated in the form of a deep red vapor, which condenses into a dark, reddish black liquid. Specific gravity, 2.97, it boils at 63°; its vapor density is 5.54 times that of air. It has an irritat ing smell, and when inhaled is poison ous. It dissolves in 30 parts of water, and the solution has weak bleaching properties. Bromine and hydrogen do not unite in the sunlight, but do when they are passed through a red hot porce lain tube, forming hydrobromic acid (HBr), which is also obtained by the action of phosphorus and water on bro mine. It is a colorless, fuming gas, which liquefies at 73°, very soluble in water. The concentrated solution con tains 47.8 per cent. of HBr, it boils at
126•, arid has powerful acid properties; it neutralizes bases, forming bromides and water. Hypobromous acid, HBrO, is only known in solutions; it has bleach ing properties. Bromine can displace chlorine from its compounds with oxy gen, while chlorine can liberate bromine from its compound with hydrogen. Free bromine turns starch yellow.
Bromine has been applied externally as a caustic, but rarely. Its chief of ficinal preparations are bromide of am monium, useful in whooping cough, in fantile convulsions, and nervous diseases generally; and bromide of potassium, now very extensively used, especially in epilepsy, hysteria, delirium tremens, diseases of the throat and larynx, bron chocele, enlarged spleen, hypertrophy of liver, fibroid tumors, etc. Also, as an antaphrodisiac, for sleeplessness, glan dular swellings, and skin diseases. Its alterative powers are similar to but less than those of the iodides. Its prepara tion is the same as iodide of potassium, substituting an equivalent quantity of bromine for iodine-6KHO+Br,=5KBr