BRA 



434 



BRA 



h: r. 



Janeiro, a revenue exceeding ten millions of French 

 hvies." 



Accordingto the author ofl\\cElat Present duPor- 

 1ui~il, thero are 12 cities in Brasil, 66 towns, many 

 villages ; one archbishop, four bishops, and about 

 430,000 inhabitants, more than one sixth of whom 

 arc Portuguese. 



See Southey's History of Brasil ; Purchas's Pil- 

 vol. iv. ; Histoirc Generate dcs Voyages, vol. 

 ' 



xv. ; Harris's J'oyages and Travels, vol. ii. ; Ray- 

 nal's East and West Indies ; Lindley's Voyage to 

 Brnsil ; Barrow's Voyage to Cochinchina, &c.; and A 

 Political Essay on the Commerce of Portugal and her 

 Colonies, particularly (if Brasil in South America, 

 by J. J. Da Cunha de Azeredo Coutinho, Bishop of 

 Fernambuco ; London 1801. 



BRASS, or LATTEN, a combination of zinc and 

 copper, is produced by the fusion of the latter me- 

 tal, and lapis calaminaris. It is capable of being 

 wrought with great facility, and is applied to a va- 

 riety of purposes in the arts. 



It is of a beautiful yellow colour, more approach- 

 ing to gold, and not so apt to tarnish or rust as cop- 

 per. It is more ductile than either that metal or 

 iron, and hence peculiarly fitted to be made into 

 wire. As brass is in general used for mathematical 

 and astronomical instruments, where the greatest 

 precision is required, its expansion has been very ac- 

 curately determined. It has been found to hold a 

 middle place between its component metals copper 

 and zinc ; and, according to Mr Smeaton, twelve 

 indie's in length of cast brass, at 30, expanded by 

 180 of heat 225 ten thousandth parts of an inch ; 

 while, in the same circumstances, hammered copper 

 expands only 204, and zinc 353 parts. Its density 

 is beyond the mean, and ought to be by calculation 

 7.6296, but is actually 8.3958. See EXPANSION. 



This beautiful alloy was known at a very early 

 period. It was first discovered from the singular cir- 

 cumstance of copper ore, and zinc earth, or cala- 

 mine, sometimes called cadmia by the ancients, 

 being found in one mine, and yielding, when melted, 

 not pure copper, but metal of a yellow colour ; and 

 from its resemblance to gold, the mines which con- 

 tained this ore were held in the highest estimation. 

 It was, however, afterwards discovered, that a cer- 

 tain earth, when added to copper, when in the fur- 

 nace, gave it a gold-colour. This earth, which must 

 have been calamine, is mentioned both by Aristotle 

 and Strabo ; and Pliny says, " Ipse lapis, ex quo Jit 

 ces, cadmia vocatur ;" 'and when speaking of the 

 Marian brass, " Hoc a Liviano ((ere) cadmium max- 

 ime sorbet." * Its use has been handed down through 

 every century, and is still retained in the manufacture 

 of brass. This discovery was no sooner effected, 

 than the ancient method of procuring this metal was 

 abandoned. Pure copper was first extracted from 

 the ore, and then converted into brass by the addi- 

 tion of calamine. But as the art of making brass 

 with lapis calaminaris was not we'll understood by 

 the ancients, but cost them much trouble and ex- 

 pence, it was esteemed next to silver ; and was reck- 



oned little inferior to that metal, as we learn from 

 Procopius, who says, " that brass, inferior to gold ' 

 in colour, is almost equal to silver in value." f It 

 was not considered as a distinct metal, but only a 

 more valuable" kind of copper ; and hence we find 

 that the word IKS, which is generally translated 

 brass, was used indifferently to denote either of the 

 two metals. The term orichalcmn, however, which 

 is used by Pliny, was more definite ; and Dr Wat- 

 son has very satisfactorily shewn, that it was confined 

 entirely to brass, while copper was called ces cypri- 

 ttm, and by later writers fiipnim. But the mines 

 which produced the orichalcum of Pliny were ex- 

 hausted in his time " Nee reperitiir longo jam tem- 

 jxtre, effceta tellure ;" \ as also the Sallustian mine 

 in Savoy, and the Livian mine in France ; and the 

 best brass then in use, was the Marian, called also 

 <es cordubense, which was found in Spain. 



In modern times, considerable improvements have 

 been made in the manufacture of this metal ; and 

 some secrecy is observed by those who have the re- 

 putation of making the finest article. This ma- 

 nufacture is carried on in most countries, but no 

 where is brass made more extensively or better than 

 in England, where both the materials are found of 

 the first quality, and in great abundance. The ope- 

 ration of making this metal is very simple, as will 

 appear from the following short description. The 

 native calamine, after the short process of calcina- 

 tion, is ground in a mill, and mixed at the same time 

 with about a fourth part of charcoal. This mixture 

 is put into large cylindrical crucibles, with alternate 

 layers of copper, cut in small pieces, or in the form 

 of shot. Powdered charcoal is then thrown over 

 the whole, when the crucibles are covered and luted 

 up. The furnace has the form of a cone, with the base 

 downwards, and the apex cut ofF horizontally. The 

 crucibles are placed upon a circular grate, or perfora- 

 ted iron plate, at the bottom, with a sufficient quanti- 

 ty of fuel thrown round them, and a perforated co- 

 ver, made of bricks or clay, is fitted to the mouth, 

 which serves as a register to regulate the heat. Af- 

 ter the copper is supposed to be sufficiently penetra- 

 ted with the zinc (the time varying in different works 

 from ten to twenty hours, according to the nature of 

 the calamine, and the size of the crucibles), the heat 

 is increased in order to fuse the whole down into one 

 mass, when the crucibles are removed, and the melt- 

 ed brass poured into moulds, and then manufactured 

 in the same way as copper plate. When the materials 

 are good, a single fusion is sufficient to make good 

 malleable brass ; but the finest sorts undergo a se- 

 cond operation with fresh calamine and charcoal. 

 Though the process in all places is nearly the same, 

 yet there is some variation in the proportion and 

 choice of the ingredients. In this country, the pro- 

 portions in weight are about 4*0 parts of copper, and 

 60 of calamine, with a sufficient quantity of char- 

 coal ; in Sweden, 40 of copper, 30 of old brass, 

 and 60 of calamine ; in France, 35 of copper, 35 if 

 old brass, 40 of calamine, and from 20 to 25 of char- 

 coal. At Goslar, in Saxony, the cadmia, or sub- 



Bra 



Nat. Hist. lib. xixiv. cap. 2. and 10. 

 $ Nat. Hist. lib. xxxiv. cap. Z. 



f De tedijkiit Justiniani, Lib. i. cap. 2. 



