908 COPPER 



The amount of moisture was only 0-4682 per cent.; but separating this from the 

 volatile matter, the complete analysis may bo thus represented : 



Carbon 647300 



Hydrogen 11-6300 



Moisture . . . . . . . 0-4682 



Ash 1-7900 



Fixed carbon 1-0050 



Oxygen, and other substances imestimated . 20-3768 



100-0000 



COOLERS, WATER. Vessels of porous unglazed earthenware, in which a 

 liquid can be kept cool by constantly exuding through the substance of the ware and 

 evaporating from the outer surface of the vessel. Such coolers, of great use in hot 

 climates, are often known by their Spanish name ALcarrazaa. 



cooiiiNG FLUIDS. See KEFRIGERATORY. 



COPAIBA, BAXiSAM OF. This oleo-rcsin is imported from Peru, and is the 

 produce of several species of Copaifera. 



COP All. A resin which exudes spontaneously from two trees, the Skits copallinum, 

 and the Elasocarpus copaliferus, the first of which grows in America, and the second in 

 the East Indies. A third species is said to grow on the banks of some rivers in, and 

 near the coasts of, Guinea. 



Much information has been received of late years from various sources concerning 

 this somewhat ill-understood product. It is now known that there are three 

 different kinds of copal in commerce, but little is known of their distinguishing 

 characteristics. "We have East Indian and West Indian copal, and, under the latter 

 name, two very different substances. The East Indian, called also African, is more 

 colourless, soft, and transparent, than the others ; it forms a fine surface, and when 

 heated emits an agreeable odour. It furnishes the finest varnish ; fresh essence of 

 turpentine dissolves it completely, but not old. Essence digested upon sulphur will 

 dissolve double its own weight, without letting any fall. Fresh-rectified oil of rose- 

 mary will dissolve it in any proportion, but if the oil is thickened by age it serves 

 only to swell the copal. 



When cautiously melted, it may be then dissolved in good essence of turpentine in 

 any proportion, producing a fine varnish of little colour. 



A good varnish may be made by dissolving 1 part of copal, 1 of essence of rose- 

 mary, with from 2 to 3 of pure alcohol. This varnish should be applied hot, and when 

 cold, becomes very hard and durable. 



The West Indian species, or American, comes to us not in lumps of a globular form, 

 but in small flat fragments, which are hard, rough, and without taste or smell. It is 

 usually yellow, and never colourless like the other. Insects are very rarely found in 

 it. It comes from the Antilles, Mexico, and North America. It will not dissolve in 

 essence of rosemary. 



The third kind of copal, known also as West Indian, was formerly sold as a product 

 of the East Indies. It is found in fragments of a concavo-convex form, the outer 

 covering of which appears to have been removed. It contains many insects. When 

 rubbed it emits an aromatic odour. It gives out much ethereous and empyreumatic 

 oil when melted. It forms a soft varnish, which dries slowly. 



Fusel-oil, or amyl spirit, has been lately used as a solvent of the hard copal ; but 

 it does not dry into a very solid varnish. 



It is now believed that the East Indian copal is the produce of Hymenaa Courbaril, 

 and perhaps also of H. verrucosa. It is probable that the Brazilian copal is yielded 

 by several species of the same genus, and by Trachylobium martianum. The African 

 copals are supposed to be the produce of certain species of Hymencea and of the 

 Guibourtia copallifera. 



COPEV. The wood of the Clusia rosea used for dyeing. 



COPPER. (Symbol, Cu. ; Atomicweufht,31'7.) One of the metals most anciently 

 known. It was named from the island of Cyprus, where it was extensively mined and 

 smelted by the Greeks. It has a reddish-brown colour inclining to yellow ; a faint 

 but nauseous and disagreeable taste ; and when rubbed between the fingers imparts 

 a smell somewhat analogous to its taste. Its specific gravity is from 8'8 to 8'9. It 

 is much more malleable than it is ductile ; so that far finer leaves may be obtained 

 from it than wire. It is said to melt at 1,996 F., and at a higher temperature it 

 evaporates in fumes which tinge flame of a bluish green. By exposure to heat with 

 access of air, it is rapidly converted into black scales of protoxide. In tenacity 

 it yields to iron; but considerably surpasses gold, silver, and platinum, in this 

 respect. 



