405 



BROMAL. 



BROMINE. 



406 



broker without having procured a licence or paid the fees, is liable to 

 a fine of 1001. for every bargain which he may negociate. 



It is usual to apply the name of broker to persons who buy and sell 

 second-hand household furniture, although such an occupation does 

 not bear any analogy to brokerage as here described, furniture dealers 

 buying and selling generally on their own account and not as agents 

 for others. These persons do indeed sometimes superadd to their 

 business the appraising of goods and the sale of them by public auction 

 under warrants of distress for rent, for the performance of which 

 functions they must provide themselves with an excise licence, and 

 also conform to the regulations of the 57 Geo. III. c. 93. 



The business of a pawnbroker is altogether different from that of 

 the commercial brokers here described. [PAWNBROKER.] 

 BROMAL. [OTHYL, COMPOUNDS or.] 

 BROMANILINE. [ANILINE.] 



BROMEIN (CjoHjBr, ?). A crystalline substance, little known, ob- 

 tained by acting with bromine upon crude hydride of phenyl. 



BROMETHIONESSIL (C M H l4 Br 4 Sj !). An unimportant derivative 

 of hydride of benzoyl. 



BROMIC ACID. [BROMINE.] 

 BROMIDES. [BROMTNE.] 



BROMINE (Br). An elementary fluid body, discovered, in 1826, by 

 M. Balard, a distinguished French chemist. The name of this sub- 

 stance is given to it from fipwuos (bromos), a stink or strong smell, on 

 account of its powerful and disagreeable odour : it was first procured 

 by its discoverer from the mother water or bittern remaining after the 

 crystallisation of common salt at the salt-works of Montpellier. It 

 was goon afterwards found in sea-water in the state of bromide of 

 magnesium, and has since been met with in various salt-springs, and 

 especially those of Germany. At Theodorshalle, near Kreutznach, it is 

 found in sufficient quantity to be extracted with advantage, 100 

 ;ivuirdupois pounds of the water yielding 2 ounces and 80 grains of 

 bromine. Dr. Daubeny has detected bromine in several mineral 

 springs in England, and he states that it occurs in most of those that 

 yield much common salt, except that of Droitwich in Worcestershire. 

 Balard has also found that it exists in marine plants growing on the 

 shores of the Mediterranean, in the ashes of sea-weeds that furnish 

 iodine, and in those of some animals, especially of the lant/uiia riolacca, 

 one of the testaceous inollusca. 



Balard obtained bromine by the following process : Into a bottle 

 two-thirds filled with bittern he passed a current of chlorine gas ; this 

 decomposed the salt of bromine contained in it, and set the bromine at 

 liberty. Ho then filled the bottle with sulphuric ether, which dis- 

 solved the bromine, and became of a fine hyacinthine-red colour ; this 

 was decanted and shaken with a solution of potash, which combined 

 with the bromine ; the solution of bromide of potassium thus obtained 

 yielded by evaporation cubic crystals of the salt ; these were powdered 

 and mixed with peroxide of manganese and sulphuric acid diluted with 

 half ita weight of water ; the bromine evolved by this process was 

 received in a vessel of cold water which condensed it. More econo- 

 mical processes have since been adopted, but this is sufficient to explain 

 the principle. 



Bromine has the following properties : It is liquid at the usual 

 temperature of the air. Ita specific gravity is 2'966. It is poisonous. 

 In considerable bulk, its colour is a deep brownish red; in small 

 quantities, it is of a hyacinthine red. Its odour is extremely strong, 

 greatly resembling that of chlorine : its taste is disagreeable. When 

 exposed to a temperature of 9'5 Fahr., it becomes solid, crystalline 

 brittle, and hard enough to be powdered. It boils at about 145'4 

 Fahr., and ite volatility Is great, for at common temperatures it emits 

 a red vapour resembling that of nitrous acid. The density of this 

 vapour ia about 5'840, and 100 cubic inches weigh about 187'4 

 grains. 



Bromine suffers no change by the agency of light, heat, or electricity, 

 and having never been decomposed, it is regarded as an elementary or 

 simple substance. In the decomposition of its compounds by electri- 

 city, it is evolved at the positive pole, and consequently resembles in 

 this respect oxygen, chlorine, and iodine, and is like them also in being 

 when vapourised, a powerful supporter of combustion, some substances 

 burning in it as in chlorine gas : its vapour extinguishes a taper ; it is 

 soluble in water and alcohol, and especially in ether ; it resembles 

 chlorine in destroying vegetable colours. It is very corrosive and 

 poisonous, acting upon and destroying organic matter with great 

 energy. It renders a solution of starch yellow. Its equivalent number 

 i* 79-U7. 



/< and bromine form only one compound, which is 

 Bromic acid (BrO,). These elements do not combine directly, but 

 only when exposed to each other in their nascent state. When, for 

 example, bromine is combined with potash, there are formed bromate 

 ol potash and bromide of potassium ; and when in the same way there 

 are formed bromate of baryta, and bromide of barium, the bromate 

 treated with sulphuric acid yields bromic acid and sulphate of baryta 

 and the aqueous solution of the acid being slowly evaporated is con 

 verted into a fluid cf the consistence of a syrup : if the evaporation is 

 carried farther, one part of the acid is volatilised, and another decom 

 posed into bromine and oxygen. 



Bromic acid has a scarcely sensible smell. It taste is sharp, but not 

 caustic. It first reddens, and then destroys, the colour of litmus paper 



Sulphurous and phosphorous acids and the hydracids decompose 

 >romic acid, and set the bromine free. Sulphuric acid also partly 

 lecomposes it into oxygen and bromine, because it absorbs the water. 

 Bromic acid is composed of 



Five equivalents of oxygen . . 8x5 = 40 

 One equivalent of bromine . . . 79-97 



Equivalent 



119-97 



Nitrogen and Bromine. These elements unite to form a detonating 

 oily liquid resembling chloride of nitrogen. Its composition is not 

 mown. 



Hydrogen and Bromine combine to form 



Hydrobromic acid (HBr). This compound is obtained with difficulty 

 by direct action, but at a high temperature these elements slowly 

 unite. Hydrobromic acid may be procured by distilling bromide of 

 potassium with concentrated sulphuric acid ; the product is mixed 

 however with bromine and sulphurous acid, because the hydrogen of 

 bhe hydrobromic acid decomposes a portion of the sulphuric acid. The 

 best method is to mix bromine and phosphorus and a little water ; 

 there is produced by their action bromide, or perbromide of phos- 

 phorus, which decomposes water, and evolves hydrobromie acid gas, 

 which may be procured in the gaseous state over mercury, or dissolved 

 in water. 



Hydrobromic acid may also be abundantly procured by decompos- 

 ing bromide of potassium with a concentrated solution of phosphoric 

 acid. 



Hydrobromic acid gas is colourless, and forms a thick vapour on 

 coming into the air. Its smell resembles that of hydrochloric acid ; its 

 specific gravity, according to Berzelius, is 2'731 ; 100 cubic inches con- 

 sequently weigh 84'72 grains. It acts upon the metals and their 

 oxides precisely in the same way as hydrochloric acid gas. It is not 

 altered by being passed through a red hot tube, either alone or mixed 

 with oxygen gas. Chlorine separates the bromine from it, and hydro- 

 chloric acid is formed. Hydrobromic acid gas is very soluble in water, 

 and the solution has a greater specific gravity than liquid hydrochloric 

 acid ; it is colourless, strongly acid, and suffers no change by exposure 

 to the air. Nitric acid decomposes it, and an aqua rcgia, is formed, 

 which dissolves gold and platinum. 



Hydrobromic acid is composed of 



One equivalent of hydrogen = 1 

 One bromine = 79-97 



Equivalent . 



80-97 



When it is decomposed by potassium, hydrogen gas, equal to half 

 the volume of the acid submitted to experiment, remains, and bromide 

 of potassium is formed. 



Chlorine and Bromine form chloride of bromine. It is prepared by 

 passing a current of chlorine gas over bromine, and condensing the 

 vapour arising, by a freezing mixture. It is liquid, has a reddish- 

 yellow colour, lighter than that of bromine. It has a strong, un- 

 pleasant smell, and its taste is extremely disagreeable. It is volatile, 

 and soluble in water : the solution possesses bleaching power. It does 

 not possess acid properties, but when mixed with the alkalies forms 

 chlorides and bromides. It has not yet been analysed. 



Sulphur and Bromine. These substances combine readily by mere 

 mixture ; the resulting bromide is iluid, has an oily appearance and 

 reddish tint. It emits white vapours when exposed to the ah-. When 

 moist it reddens litmus paper strongly, but slightly when dry. Boiling 

 water is decomposed by bromide of sulphur, and there are produced 

 hydrobromic, hydrosulphuric, and sulphuric acids. Its composition is 

 unknown. 



Phosphorus and bromine combine readily to form two compounds ; 

 the terbromide is liquid, and the perbromide is solid. The terbromide 

 (PBr 3 ) is composed of three equivalents of bromine 239-91, and one 

 of phosphorus 32'02 = 271 '93. Both bromides are prepared by mixing 

 these elements in a flask containing carbonic acid gas : action takes 

 place, with evolution of light and heat, and there are formed the solid 

 perbromide which sublimes in the upper part of the flask, while the 

 fluid terbromide remains in the lower part. 



The perbromide (PBr 5 ) is of a yellow colour ; by heat it becomes 

 red. It decomposes water, and there are formed hydrobromic and 

 phosphoric acids. 



Bromine and iodine form probably two bromides of iodine ; the 

 protobromide, or that so considered, is a solid compound, which is by 

 heat convertible into a reddish-brown vapour, condensing into small 

 crystals of the same colour, resembling feru leaves in appearance. 



When bromine is added to the above described crystals a liquid is 

 formed, which unites with water and gives a solution possessing 

 bleaching power. It is probably the perbromide of iodine. 



We have now mentioned the principal binary compounds of bromine, 

 except those which contain a metal : for these as well as for an account 

 of the bromates which their oxides form with bromic acid, we refer to 

 each particular metal. 



Bromine and its compounds are employed in photography, they are 

 also much used in organic chemical research, and the bromide of 

 potassium has been employed in medicine. 



