Tin Copper Per cent. Copper 11 108 = 90·76 Cannon, statues, machine brasses. 11 99 = 90 ‘Gun-metal’ proper (cannon). 11 84 = 84·44 ‘Gun-metal,’ machinery bearings. 11 72 = 86·75 Harder composition. 11 60 = 84·50 Not malleable. 11 44 = 80 Cymbals, Chinese gongs. 11 48 = 81·35 Very hard, culinary vessels. 11 36} = {76·69} ‘Bell-metal.’ 12 36} {75·00} 11 24 = 68·57 Yellowish, very hard, sonorous. 11 4 = 26·66 Very white,[283] specula.[284] The most popular alloy of copper, next to bronze, is brass, which is harder and wears better than the pure metal. Originally, as now, it was a mixture of copper and zinc, popularly called spelter (old _speautre_, _speauter_, _spiauter_, _spialter_).[285] The proportions greatly varied, one part of the latter to two of the former being the older ratio, and the density increasing with the amount of copper from 8·39 to 8·56. Beckmann tells us, in his valuable ‘History of Inventions,’[286] ‘in the course of time an ore which must have been calamine (carbonate of zinc) or blende[287] (sulphuret of zinc), was added to copper, and gave it a yellow colour. The addition made it harder, more fusible and sonorous, easily subject to the lathe, more economical to work, and a worse conductor of heat than the pure metal.’ We have few specimens of old art-works in ‘brass’ proper, although zinc was discovered by analysis in an ancient Sword, chiefly copper.[288] Gibel assures us that zinc occurs only in Roman alloys, the bronze of the Greeks containing nothing beyond copper, tin, and lead. The Romans also could varnish or lacquer brass, but it is not known whence they derived the art. Percy notes (p. 521) that brass was produced ‘early in the Christian era, if not before its commencement.’ He quotes in proof a large coin of the Cassia Gens (B.C. 20) which contained copper 82·26 and zinc 17·31; a Vespasian (Rome, A.D. 71), an imperial Trajan (Caria, circ. A.D. 110), a Geta (Carian Mylasa, A.D. 189–212), a Greek Caracalla (A.D. 199), and many others. In modern times zinciferous ore was imported by the Portuguese from the East a century before it was common throughout Europe.[289] In the early seventeenth century the Dutch captured one of their craft laden with spelter, and the secret became known. Bishop Richard Watson says (1783) the cargo was _calaem_, which he connects with ‘calamine’: the latter, like the German _Galmei_, derives from _cadmia_.