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    "source_title": "Encyclopaedia Britannica (1911)",
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    "chunk_id": "1911:brass:80ef7985796f",
    "title": "BRASS",
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    "verified_text": "brass, a river, town and district of southern nigeria, british west africa. the brass river is one of the deltaic branches of the niger, lying east of the rio nun or main channel of the river. from the point of divergence from the main stream to the sea the brass has a course of about 100 m., its mouth being in 6 deg. 20' e., 4 deg. 35' n. brass town is a flourishing trading settlement at the mouth of the river. it is the headquarters of a district commissioner and the seat of a native court. its most conspicuous building is a fine church, the gift of a native chief. the capital of the brass tribes is nimbe, 30 m. up river. the brass river, called by its portuguese discoverers the rio bento, is said to have received its english name from the brass rods and other brass utensils imported by the early traders in exchange for palm-oil and slaves. the brass natives, of the pure negro type, were noted for their savage character. in 1856 their chiefs concluded a treaty with great britain agreeing to give up the slave-trade in exchange for a duty on the palm-oil exported. finding their profitable business as middlemen between the up-river producer and the exporter threatened by the appearance of european traders, they made ineffective complaints to the british authorities. the establishment of the royal niger company led to further loss of trade, and on the 29th of january 1895 the natives attacked and sacked the company's station at akassa on the rio nun, over forty prisoners being killed and eaten as a sacrifice to the fetish gods. in the following month a punitive expedition partially destroyed nimbe, and a heavy fine was paid by the brass chiefs. since then the country has settled down under british administration. the trade regulations of which complaint had been made were removed in 1900 on the establishment of the protectorate of southern nigeria (see nigeria). valuable information concerning the country and people will be found in the _report by sir john kirk on the disturbances at brass (africa_, no. 3, 1896). brass (o. eng. _braes_), an alloy consisting mainly if not exclusively of copper and zinc; in its older use the term was applied rather to alloys of copper and tin, now known as bronze (q.v.)thus the brass of the bible was probably bronze, and so also was much of the brass of later times, until the distinction between zinc and tin became clearly recognized. the latin word _aes_ signifies either pure copper or bronze, not brass, but the romans comprehended a brass compound of copper and zinc under the term _orichalcum_ or _aurichalcum_, into which pliny states that copper was converted by the aid of cadmia (a mineral of zinc). in england there is good evidence of the manufacture of brass with zinc at the end of the 16th century, for queen elizabeth by patent granted to william humfrey and christopher schutz the exclusive right of working calamine and making brass. this right subsequently devolved upon a body called the \"governors, assistants and societies of the city of london of and for the mineral and battery works,\" which continued to exercise its functions down to the year 1710. when a small percentage of zinc is present, the colour of brass is reddish, as in _tombac_ or red brass, which contains about 10%. with about 20% the colour becomes more yellow, and a series of metals is obtained which simulate gold more or less closely; such are _dutch metal, mannheim gold, similar_ and _pinchbeck_, the last deriving its name from a london clockmaker, christopher pinchbeck, who invented it in 1732. ordinary brass contains about 30% of zinc, and when 40% is present, as in _muntz, yellow_ or _patent_ metal (invented by g.f. muntz in 1832), the colour becomes a full yellow. when the proportion of zinc is largely increased the colour becomes silver-white and finally grey. the limit of elasticity increases with the percentage of zinc, as also does the amount of elongation before fracture, the maximum occurring with 30%. the tenacity increases with the proportion of zinc up to a maximum with 45%; then it decreases rapidly, and with 50% the metals are fragile. by varying the proportion between 30 and 43% a series of alloys may be prepared presenting very varied properties. the most malleable of the series has an elongation of about 60%, with a tensile strength of 17.5 tons per sq. in. increase in the proportion of zinc gives higher tensile strength, accompanied, however, by a smaller percentage of elongation and a materially increased tendency to produce unsound castings. the quality of copper-zinc alloys is improved by the addition of a small quantity of iron, a fact of which advantage is taken in the production of aich's metal and delta metal. of the latter there are several varieties, modified in composition to suit different purposes. some of them possess high tensile strength and ductility. they are remarkably resistant to corrosion by sea-water, and are well suited for screw-propellers as well as for pump-plungers, pistons and glands. heated to a dull red delta metal becomes malleable and can be worked under the hammer, press or stamps. by such treatment an ultimate tensile strength of 30 tons per sq. in. may be obtained, with an elongation of 32% in 2 in. and a contraction of area of 30%. in the arts brass is a most important and widely used alloy. as compared with copper its superior hardness makes it wear better, while being more fusible it can be cast with greater facility. it is readily drawn into fine wire, and formed into rolled sheets and rods which are machined into a huge number of useful and ornamental articles. it is susceptible of a fine polish, but tarnishes with exposure to the air; the brilliancy of the surface can, however, be preserved if the metal is thoroughly cleansed by \"dipping\" in nitric acid and \"lacquered\" with a coating of varnish consisting of seed-lac dissolved in spirit.",
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