534 BRONZE 



BRITTLE SULPHTTRET OF SILVER. See SITAT.R ORES. 



BROAD CLOTH. A fino kind of woollen cloth, which exceeds twenty-nine 

 inches in width. All of loss width are known as narrow cloths. 



BROAD GAUGE. Bails laid wide apart, as on the Great Western Railway and 

 its branches, in contradistinction to the nairow gauge, as on all the other railways of 

 the Kingdom. The broad gauge rails are 6 feet apart ; the narrow gauge rails 4$ feet. 



BROAD LEAF. The Terminalia latifolia, a tree, native of Jamaica, the wood of 

 which is used for boards, scantlings, shingles, and staves. It is sometimes mistaken 

 for the almond tree, owing to the shape of its fruit. See TERMINALLY. 



BROADSIDE. A seaman's term the full length or side of a ship. A printer's 

 term* full printed page of any sized sheet. 



BROCADE. A rich stout silk, formerly much worn by ladies of rank. A name 

 commonly given to any variety of stuff upon which raised flowers are embroidered. 

 The name is also given to a cloth of silk and gold manufactured in Eastern countries. 



BROCATELLE. Linsoy-woolsoy is so called in France. A silk material which 

 is used for lining carriages. 



BROCATELLI MARBLE. An artificial marble made from fragments of 

 natural marbles united by means of an artificial cement. 



BROCHANTITE. An ore of copper found ia this country at Eoughton Gill, in 

 Cumberland. It has also been discovered in Siberia, Nassau, and elsewhere. Its 

 composition is sulphuric acid, 17'7; protoxide of copper, 70'3; water, 12 - 0. 



BROCZCRAM. A Cumberland miner's term for a breccia. 



BROIMCA. A preparation of chocolate. 



BROM ACETIC ACID. Obtained by Messrs. Perkin and Duppa. They take 

 a mixture of crystallisable acetic acid and bromine in the proportion of equal 

 equivalents, introduce it into a sealed tube, which is placed in an oil bath and heated 

 to" 150 C. The mixture which is nearly colourless, or of a light amber colour, is 

 transferred to a retort, and the excess of acetic acid driven off by heating to 200 C. 

 On cooling, a beautiful white crystalline solid is obtained, which is bromacetic acid, 

 together with hydrobromic acid and bibromacetic acid. The mixed acids are heated to 

 130 C., carbonic acid passed until the reaction of hydrobromic acid, with nitrate of 

 silver, is no longer evident. Carbonate of lead is then added, the whole heated to 

 100 C., and allowed to stand for some hours ; the liquid filtered off from the 

 crystalline deposit. 



The acid thus obtained crystallises in rhombohedra, is exceedingly deliquescent, and 

 very soluble in water 6r alcohol. It fuses below 100 C., and boils at 208 C. When 

 distilled with acetate of potassium, it gives off acetic acid ; when heated with metallic 

 zinc, it yields acetate and bromide of zinc. 



It attacks the epidermis powerfully, raising a blister like that produced by a burn. 

 It forms crystallisable salts with most bases, many of which decompose rapidly. 



Messrs. Perkin and Duppa have formed the salts of the alkalis and alkaline earths. 

 The lead salt is obtained by neutralising bromacetic acid with oxide of lead, and 

 recrystallising in water, washing the crystalline precipitate with cold water, and re- 

 crystallising from water. 



The silver salt is obtained by treating bromacetic acid with carbonate of silver, or 

 by adding solution of bromacetic acid to solution of nitrate of silver. It is thrown 

 down as a crystalline precipitate. 



Bromacetato of methyl is a colourless mobile liquid, having an aromatic odour ; it 

 boils at 144 C. The bromacetate of ethyl boils at 159 C. ; that of amyl at 207 C. 



By the action of ammonia on bromacotic acid, bromide of ammonium is formed, 

 and glycocol, or a body isomeric with it. 



Bibromacetic Add. Formed when bromine and acetic acid are heated in pre- 

 sence of light, but it is difficult to obtain in large quantities. It is a liquid boiling at 

 240 C., which is partially decomposed every time it is distilled, evolving hydro- 

 bromic acid. It does not solidify at 15 C. It has a very high specific gravity. 

 The silver salt is a crystalline precipitate which is, however, decomposed, by 

 boiling with water, into bromide of silver and a soluble acid. 



BROXVIATES. Compounds of BROJIIC ACID with alkalis, alkaline earths, and 

 metals. 



BROMIC ACID. A combination of bromine with oxygen, forming bromates. 



BROMIC SILVER. See SILVER OSES. 



BROMIDES. Compounds of BROMINE with alkalis and metals. 



BROMIDE OF SILVER. A salt much used in photography. It is formed 

 by adding a soluble bromide to nitrate of silver, when a white precipitate is produced. 

 See PHOTOGRAPHY. 



BROMXTE. Native bromide of silver. 



BRONZE. (Bronze, Fr. and Ger.) A compound metal consisting of copper 



