542 BROMINE 



iron from rust, and also improves ita appearance, is chiefly employed for the barrels of 

 fowling-pieces and soldiers' rifles, to conceal the fire-arms from the game and the 

 enemy. The finest kind of browning is the Damascus, in which dark and bright linos 

 run through the brown ground. 



This operation consists in producing a very thin uniform film of oxide or rust upon 

 the iron, and giving a gloss to its surface by rubbing wax over it, or coating it with a 

 shell-lac varnish. 



Several means may be employed to produce this rust speedily and well. The effect 

 may be obtained by inclosing the barrels in a space filled with the vapour of muriatic 

 acid. Moistening their sxirface with diluted muriatic or nitric acid will answer the same 

 purpose. But the most common material used for browning is the butter or chloride 

 of antimony, which, on account of its being subservient to this purpose, has been 

 called bronzing salt. It is mixed uniformly with olive-oil, and rubbed upon the iron 

 slightly heated, which is afterwards exposed to the air, till the wished-for degree of 

 browning is produced. A little aquafortis is rubbed on after the antimony, to quicken 

 its operation. The brown barrel must be then carefully cleaned, washed with water, 

 dried, and finally polished, either by the steel burnisher, or rubbed with white wax, 

 or varnished with a solution of 2 ounces of shell-lac and 3 drachms of dragon's blood, 

 in 2 quarts of spirits of wine. 



The following process may also be recommended : Make a solution with half an 

 ounce of aquafortis, half an ounce of sweet spirits of nitre, 1 ounce of spirits of wine, 

 2 ounces of sulphate of copper, and 1 ounce of tincture of iron, in so much water as 

 will fill together a quart measure. The gun-barrel to be browned must first of all be 

 filed and polished bright, and then rubbed with unslaked lime and water to clear 

 away all the grease. Its two ends must now be stopped with wooden rods, which 

 may serve as handles, and the touch-hole must be filled with wax. The barrel is 

 then to be rubbed with the solution, applied to linen rags or a sponge, till the whole 

 surface be equally moistened ; it is allowed to stand 24 hours, and is then scrubbed 

 off with a stiff brush. The application of the liquid and the brushing may be re- 

 peated twice or oftener, till the iron acquires a brown colour. After the last brushing, 

 the barrel must be washed with plenty of boiling water containing a little potash, 

 then washed with clean water, dried, rubbed with polishing woods, and then coated 

 with shell-lac varnish. 



BROMIDES. Compounds of bromine with electro-positive elements. 



BROMINE. (Symb. Br.; Atomic weight, SO. Density in liquid state, 2'97. Density 

 of vapour by experiment, 5'39 ; by calculation, 5'536, on supposition of the density of 

 hydrogen being 0'0692). This element exists in very small quantity in sea-water, and 

 to a larger extent in certain mineral springs, as those of Kreuznach and Kissingen. 

 The water of the Dead Sea is comparatively rich in bromine a sample taken from a 

 depth of 300 metres having yielded M. Lartet 07 per cent, of this element. The 

 mother-liquors of many brine springs, especially those of Schonebeck, near Magdeburg, 

 are rich in bromides. The element also occurs in carnallite and some of the other 

 salts worked at Stassfurt, and in two silver ores found in th<? mines of Mexico and 

 Chile, and known as bromyrite, or bromide of silver, and embolite or chloro-bromido of 

 silver. Megabromite and inicrobromilc are names applied to ill-defined varieties of 

 embolito, according as they contain more or less bromine. 



Bromine was discovered in 1826, by Balard, of Montpellier, in the bittern produced 

 from the water of the Mediterranean. Bromine is a very interesting substance, and 

 its discovery has had great influence on the progress of theoretical and applied 

 chemistry. It is the only element, save mercury, which exists in the liquid state at 

 ordinary temperatures. The liquid presents a deep brownish-red colour, and emits 

 dense reddish vapours, which are extremely irritating when breathed. Its odour is 

 sufficiently characteristic to have given the element its name (&p(a/j.os, a stench). 

 Bromine is slightly soluble in water, one part requiring 30 parts of water for its solu- 

 tion. The aqueous solution is of a yellowish tint when freshly made, but is readily 

 decomposed by exposure to light. It forms a definite crystalline hydrate with five 

 atoms of water. Bromine is much more soluble in alcohol or in ether. Exposed to a 

 temperature of about 145 Fahr. bromine boils, and at 9'5 it freezes to a red crys- 

 talline solid. 



Preparation 1. From bittern. Chlorine gas is passed in for sometime; this has 

 the effect of combining with the metallic base of the bromide present, the bromine 

 being, in consequence, liberated. When the bittern no longer increases in colour, the 

 operation is suspended or chloride of bromine would be formed, and spoil the operation. 

 The coloured fluid is placed in a large globe, with a neck having a glass stopcock 

 below like a tap funnel, the upper aperture being closed with a stopper. Ether is then 

 added, the stopper replaced, and the whole well agitated. After a short repose, the 

 ether rises to tho surface, retaining the bromine in solution. The stopper being 



