730 GONG-GONG 



GOLD, CHLORIDE pP. Trichloride of gold. This salt is formed when gold 

 is dissolved in nitro-muriatic acid. It is much used in photography. 



GOLD COINAGE. The current gold coins of the United Kingdom are the 

 sovereign and the half-sovereign. See MINT ; SOVEREIGN. 



COLD X.ACE. Gilt silver wire, woven into a lace. 



GOI.D-I.EAr. See GOLD-BKATINQ. 



GOXiD, MANNHEIM. A brass composed of from 3 to 4 ounces of zinc to 1 

 pound of copper. See BRASS. 



GOX.D, MOSAIC. A brass of very fine colour used in common jewellery. 

 Hamilton and Parker's patent Mosaic gold consists of 16 ounces of zinc to 16 ounces 

 of copper. It is of a dark colour when first cast, but on dipping assumes a beautiful 

 golden tint. The patentees say, ' when cooled and broken, all yellowness must cease, 

 and the tinge vary from reddish fawn or salmon colour, to a light purple or lilac, and 

 from that to whiteness.' See BRASS ; AIXOYS. 



GOXiD-PURPIiE. See PURPLE OF CASSIUS. 



GOLD, SALTS OF. The bromide, cyanide, iodide, phosphide, sulphide, and 

 some other salts of gold which are rarely used in the arts, are fully described in 

 Watts's ' Dictionary of Chemistry.' 



GOLD OP PLEASURE. A plant cultivated on the Continent for its seeds, 

 which yield a fine oil, while its fibres can be employed in the manufacture of sail-cloth, 

 packing, and other coarse articles. It is the Camelina sativa of botanists. It has not 

 attracted much attention in this country. 



GOLD THREAD, or spun gold, is a flatted silver-gilt wire, wrapped or laid 

 over a thread of yellow silk by twisting with a wheel or iron bobbins. By the aid of 

 a mechanism like the braiding machine, a number of threads may thus bo twisted at 

 once by one master wheel. The principal nicety consists in so regulating the move- 

 ments that the successive volutions of the flatted wire on each thread may just touch 

 one another, and forms a continuous covering. The French silver for gilding is said 

 to be alloyed with 5 or 6 pennyweights, and ours with 12 pennyweights, of copper in 

 the pound troy. The gold is applied in leaves of greater or less thickness, according 

 to the quality of the gilt wire. The smallest proportion formerly allowed in this 

 country by Act of Parliament was 100 grains of gold to one pound, or 5,760 grains of 

 silver ; but more or less may now be used. The silver rod is incased in the gold-leaf, 

 and the compound cylinder is then drawn into round wire down to a certain size, 

 which is afterwards flatted in a rolling mill, such as is described under MINT. 



The liquor employed by goldsmiths to bring out a rich colour on the surface of 

 their trinkets is made by dissolving 1 part of sea-salt, 1 part of alum, 2 parts of nitre, 

 in 3 or 4 of water. The pickle or sauce, as it is called, takes up not only the copper 

 alloy, but a notable quantity of gold ; the total amount of which in the Austrian 

 Empire has been estimated annually at 47,000 francs. To recover this gold the liquor 

 is diluted with at least twice its bulk of boiling water, and a solution of very pure 

 green sulphate of iron is poured into it. The precipitate of gold is washed upon a 

 filter, dried, and purified by melting in a crucible along with a mixture of equal parts 

 of nitre and borax. 



GOLD-THREAD. The bitter root of the Coptis trifoliata, used in North 

 America as a tonic. 



GOI.D WIRE is formed by drawing a cylindrical rod of the metal, as pure as in.-iy 

 be, through a series of holes punched in an iron plate, diminishing progressively in 

 size. The gold, as it is drawn through, becomes hardened by the operation, and re- 

 quires frequent annealing. 



GOLDEN 1VXARCASXTE. A name given at one time to the metal zinc. 

 Albertus Magnus calls it Marchasita aurea. ' This was properly a stone, the metallic 

 particles of which were so entirely sublimated by fire, that nothing but useless ashes 

 remained behind. It contained fixed quicksilver, communicated a colour to metals, on 

 which account it was well known to the alchemists, burned in the fire, and was at 

 length entirely consumed. It was found in various parts, but that at Goslar was the 

 best, because the copper it contained seemed to have in it a mixture of gold. To give 

 this copper, however, a still greater resemblance to gold, some tin w r as added to it, by 

 which means it became more brittle. This marchasita also rendered copper white as 

 silver. Thus far Albertus. It obtained without doubt the name of Marchasita in/r> a 

 because zinc communicates a yellow colour to copper ; and for the same reason the 

 Greeks and the Arabians called Cadmia golden, or aurca. 1 Beckmann. 



GOLDEN SULPHT7RET OP ANTIMOMTY. Stibium SidpJmratum Auran- 

 ticum. The pentasulphide of antimony, a golden yellow powder, its formula IK. ing 

 SbS 5 (Sb 2 S 5 ). See ANTIMONY. 



GONG-GONG, or Tam-tam of the Chinese. A kind of cymbal made of a copper- 

 alloy. See COPPKK. 



