658 



THE STANDARD DICTIONARY OF FACTS 



Coke, the carbonaceous residue of coal , 

 which has been heated in an oven or retort, or 

 in any way by which little air is admitted, until 

 all volatile matter has been expelled. The 

 simplest method of producing coke is based on 

 the preparation of wood charcoal, the coal being 

 arranged in heaps which are smothered with 

 clay or coal-dust, and then set on fire, sufficient 

 air being admitted to keep the mass at the proper 

 temperature for decomposition without wasting 

 the coke. After the volatile portions are got 

 rid of, the heap is allowed to cool, or is extin- 

 guished witli water, ami the coke is then ready. 

 Methods of heating the coal in close or open 

 until the gaseous and fluid products are 

 driven off are also commonly used. Gas-coke is 

 that which remains in the retorts after the gas 

 has been given off. Good oven-coke has an iron- 

 iray color, sub-metallic luster, is hard, and some- 

 what vesicular; but gas-coke has rather a 

 1 and cindery look, and is more porous. 

 Coke contains about ninety per cent, of carbon, 

 and is used where a strong heat is wanted with- 

 out smoke and flame, and it is accordingly largely 

 consumed in drying malt and similar purposes. 

 It used to be burned regularly in locomotive- 

 engines, but raw coal is now commonly substi- 

 tuted. The largest quantities are consumed in 

 smelting operations. 



Cold Storage. A system for the preser- 

 vation of fruits, meats, and other food stuffs, 

 in which the air of the storage chambers is 

 kept near or below the freezing temperature 

 by refrigerating methods similar to those 

 employed in making artificial ice. By this 

 means food can be kept in an unchanged 

 state for an indefinite period. The system is 

 widely applied both on land and in ocean 

 steamers. 



Copper, one of the most anciently known 

 metals, deriving its name from Cyprus, large 

 supplies having in Greek and Roman times come 

 from that island. Next to gold, silver, and 

 platinum it is the most ductile and malleable of 

 metals ; it is more elastic than any metal except 

 steel, and the most sonorous of all except alu- 

 minium. Its conducting power for heat and elec- 

 tricity is inferior only to that of silver. It has a 

 distinct odor and a nauseous metallic taste. 

 It is not altered by water, but tarnishes by ex- 

 posure to the air, and becomes covered with a 

 green carbonate. It occurs native in branched 

 pieces, dendritic, in thin plates, and rarely in 

 regular crystals, in the primitive and older 

 secondary rocks. Blocks of native copper have 

 sometimes been got weighing many tons. Its 

 ores are numerous and abundant. All the com- 

 pounds of copper are poisonous. It is found in 

 most European countries, in Australia and Japan, 

 in Africa and in North and South America 

 (especially in the vicinity of Lake Superior). 

 In Britain the mines of Cornwall are the richest. 



Copper is extracted from its ores either by the 

 dry or the wet process. For the former, what is 

 known as the Welsh process is most common in 

 Great Britain. It consists in alternately roast- 

 ing the ore, and then smelting it in a furnace 

 with a suitable slag, until impure or blister cop- 

 per is obtained. Before this stage is reached 

 a metallic compound of copper, sulphur, and 



iron lias been produced, technically known as 

 matt, regulus, or coarse metal, and subsequently 

 a tolerably pure sulphide of copper called tine 

 metal. The blister copper is refined by burning 

 otY the sulphur, arsenic, and other volatile im- 

 purities, and by melting it along with wood char- 

 coal and stirring it with a wooden pole. The 

 quality is then tested, and, if found satisfactory, 

 trie copper is cast into ingots. In extracting the 

 metal from pyrites by the wet process, the ore is 

 first roasted to get rid of the larger proportion 

 of sulphur, then the calcined residue still con- 

 taining sulphur is mixed with common salt, 

 ground and heated in ovens. The copper is thus 

 converted into chloride, part of which volatilizes, 

 but is condensed, along with arsenic and other 

 substances, by passage through flues and water- 

 condensers. After some hours the calcined mix- 

 ture is raked out of the ovens, cooled, and t ra in- 

 ferred to tanks, where it is exhausted by suc- 

 cessive treatment with water. The solution, 

 containing chloride of copper, sulphate and 

 chloride of sodium, and iron salts, is next healed 

 along with scrap-iron. Copper precipitates in 

 the form of a ruddy, lustrous, tolerably compact 

 mass, with a crystalline appearance, and mixed 

 with metallic-iron and oxide. The larger pieces 

 of iron are picked out, the precipitate washed 

 and drained, and then rendered compact by 

 heating in a furnace. A slag containing the 

 oxide of iron forms, and the copper, when 

 judged sufficiently pure, is run into moulds. 

 Afterwards this crude metal is refined and 

 toughened. 



Some of the alloys of copper, especially those 

 containing tin and zinc, are of considerable 

 importance, e. g., bronze, an alloy of copper 

 with about eight or ten per cent, of tin; bell- 

 metal composed of eighty parts of copper and 

 twenty of tin; British bronze coinage, copper 

 ninety-five, tin four, zinc one. 



Copper is applied to a great many useful pur- 

 poses. In sheets it is used for sheathing the 

 bottoms of ships, covering roofs and domes, the 

 constructing of boilers and stills of a large size, 

 etc. It is also used in electrotyping and en- 

 graving, for various household untensils and lit 

 tings ; but its use for household utensils is by no 

 means free from danger on account of the action 

 of acids on it, which, produces verdigris. 



The copper production in the world, in 1906, 

 was as follows: United States, 416,226 tons; 

 Spain and Portugal, 50,109; Chile, 26,157; 

 Japan, 40,528; Germany, 20,665; Mexico, 

 62,690; Australasia, 36,830; Canada, 19,106; 

 other localities, 36,312. 



In the United States, Montana, Arizona, and 

 Michigan are the chief copper producing States. 



Cotton. A soft, downy substance, consist- 

 ing of fine hair growing round the seeds of plants 

 belonging to the genus Gossypium, O. Malvacece. 

 The genus is indigenous to ooth the American 

 and Asiatic continents, but it has been so ex- 

 tensively spread by means of cultivation that it 

 is now found throughout all parts of the world, 

 within the limits of 36 north and south of the 

 equator. All the species and varieties form 

 herbaceous or shrubby perennial plants, varying 

 in height according to the climate and soil in 

 i which they grow, some not exceeding two or three 



