BROMINE, a non-metallic element. bol Br; atomic weight, 79.4 for H =1, or 80.0 for 0=16. Bromine was discovered in 1826 by Balard, in the salts obtained by the evapora tion of sea water. Bromine is not found in an uncombined form in nature but exists as a constituent in all sea water and in most mineral waters and salt springs. It is liberated from its sodium and magnesium salts by the action of free chlorine, and is separated by ether, which dissolves the bromine. This red-colored solu tion is removed, saturated with potash, evapo rated and heated to redness, and the bromide of potassium is heated with manganese dioxide and sulphuric acid. The bromine is liberated in the i form of a deep red vapor, which condenses into a dark, reddish-black liquid, which is mobile, and volatile, and has a specific gravity of 2.97. It boils at 63°, and its vapor density is 5.54 times that of air. It has an irritating smell, and when inhaled is poisonous. On account of this poisonous quality and the great vapor density it was used largely in the making of the asphyxiating gases employed in the Euro pean War (see Boum). 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 porcelain tube, form ing hydrobromic acid (HBr), which is also ob tamed by the action of phosphorus and water oa bromine. It is a colorless, fuming gas, which liquefies at 73° very soluble in water. The con centrated solution contains 47.8 per cent of HBr; it boils at 126°, and has powerful acid properties; it neutralizes bases, forming bro. mides and water. Hypobromous acid, HBrO, is only known in solutions; it has bleaching properties. Bromine can displace chlorine from its compounds with oxygen, while chlorine can liberate bromine from its compounds with hy drogen. Free bromine turns starch yellow.
In the arts bromine is used in very large quantities in making the sensitive silver salts employed in photography. It is also used to dissolve gold in metallurgical processes, and in the manufacture of dyes and disinfectants. In medicine bromine has been applied externally as a caustic but rarely. Its chief officinal prep
arations are bromide of ammonium, useful in whooping-cough, infantile convulsions and ner vous diseases generally; and bromide of potas sium, very extensively used as a depressant of the nervous system, especially in epilepsy, hysteria, delirium tremens, diseases of the throat and larynx, bronchocele, enlarged spleen, hypertrophy of liver, fibroid tumors, etc. Also, as an antaphrodisiac, for sleeplessness, glandular swellings and skin diseases. The alterative properties of bromide of potassium are similar to, but less marked than, those of the iodides. Its preparation is the same as iodide of potas sium, substituting an equivalent quantity of bromine for iodine —6KHO Bra 5KBr KBrO. 3H.O. It has a pungent saline taste, no odor and occurs in colorless cubic crystals, closely resembling the iodide. As a hypnotic its usefulness is much increased by combining it with morphia or chloral hydrate. Bromine is manufactured chiefly from the mother liquors of saltworks. In the United States the largest production comes from the natural brines of the salt wells of Michigan. Other localities of note are Pomeroyhio, and a few points in P West Virginia. Previous to the outbreak of the European War the Michigan and Ohio product was manufactured into fine chemicals, the average amount produced annually being about 600,000 pounds, and the average price about 20 cents per pound. By 1915 the output had been placed on the market largely in crude form, and the amount totaled 855,857 pounds, the price rapidly advancing to as high as $6.50 per pound in the early part of 1916. The de mand from abroad decreasing, the output for 1916 fell to 688,260 pounds, for which an aver age price of $1.34 per pound was obtained, ag a value of $922,225. See MINERAL RODTJCITONS OF THE UNITED STATES. BROMIPIN, a yellow, bland liquid of simple oily taste, and composed of oil of sesame with 10 per cent of bromine. It is easily borne by the stomach and does not readily produce bromism, therefore in some cases it is sub stituted for the bromides which it resembles in its action on the nervous system.