573 CALCAREOUS TUFA 



Blanchet, the composition of oil of cajuput is, carbon 77'92, hydrogen 11'69, oxygen 

 10'39. It is used in medicine as a stimulant. See OILS, ETHBREOUS. 



CAKING COAL. A coal which fuses together when heated. All the caking 

 coals are bituminous, and usually make good coke. See COAL. 



CAL or XAL, sometimes CALLEN. A miner's term for iron ochre, especially 

 in St. Just in Cornwall. The term is sometimes applied to Wolfram. 



C ALABA-TREE, Calophyllum Calaba, so called from the beauty of its leaves. 

 From tho roots of several species an oil is expressed, which is used for burning in lamps, 

 and from the incised trunk a resin is obtained, which is known in commerce by the 

 name of Tacamahaca gum. The true calaba tree is a native of the Caribbee Islands ; 

 it grows to the height of sixty feet, and its wood is much valued for staves and for 

 cask headings. 



CALABAR BEAN. See ORDEAL BEAK. 



CALABAR-SKIN. The skin of the Siberian squirrel is sometimes so called. It 

 is imported and used for making muffs and trimmings. * 



CALABASHES. The pericarp of the fruit of the Calabash tree, one of tho 

 Bignoniacees (Crescentia cujete). It is a native of the tropical regions of America, 

 and produces a melon-like fruit, containing a slightly acid pulp, which is sometimes 

 eaten. After the removal of the pulp, the pericarp is used for cups, bottles, baskets, &c. 



CALAITE. See TURQTJOIS. 



CALAMANCO. A sort of woollen stuff of a shining appearance, chequered in 

 the warp, so that the checks are seen only upon one side. 



CALAMANDER. A wood, the produce of a species of Diospyros, from Ceylon. 

 See COROMANDEL. 



CALAIVIINE. Unfortunately, there is some confusion among mineralogists in 

 the application of this term. It appears that the Lapis calaminaris of the older 

 writers included two distinct ores of zinc the carbonate and the hydrous silicate. In 

 the early part of this century Smithson pointed out the differences between the two 

 species. Brongniart soon afterwards gave the name of Calamine to the silicate, and 

 several years later Beudant proposed the term Smithsonite for the carbonate. This 

 usage of the names is still retained by Dana and by certain Continental writers, but 

 English mineralogists have been accustomed to reverse this use of the terms. In this 

 country, therefore, the carbonate of zinc is invariably distinguished as calamine, whilst 

 the silicate is known as Smithsonite or Electric Calamine. See ZINC. * 



CALAMINE, ELECTRIC. Hydrous silicate of zinc, known otherwise as 

 Smithsonite or Hemimorphite. The term ' electric,' applied to this mineral, refers to 

 its pyroelectric properties, or its power of exhibiting electric polarity when heated, tho 

 two extremities of a heated crystal assuming opposite electrical conditions. 



CALAMUS (KoAajuos, a reed). A genus of plants belonging to the palm tribe. 

 The C. Eotang and C. Scipionum are mentioned as two species which produce the 

 Kattan canes of commerce. The Dragon's Blood of commerce is obtained from 

 the C. Draco, a native of Sumatra and Borneo. See DRAGON'S BLOOD ; KATTAN. 



CALAMUS AROMATICUS. The Acorus, or sweet Flag. The drug sold 

 under this name in our shops is the produce of the Acorus calamus. The plant is a 

 native of this country, of various parts of Europe, and of India. The Indian variety 

 furnishes a famous medicine in the Levant, while the Turks candy it and regard it as 

 a remedy against contagion. The rushes which were formerly strewn over tho floors 

 of rooms were the leaves of this plant. It has been said that the Acorus calamus is 

 sometimes employed in rectifying gin. By distillation it yields a volatile oil used 

 in scenting snuff, and in the production of aromatic vinegar. 



CALCANTHUM. See CHALCANTHUM. 



CAXiCAR. A name given by glass-makers to a small furnace in which tho 

 first calcination is made of sand and potash for the formation of a. frit, from which 

 glass is made. 



CALCAREOUS EARTH (Terre calcaire, Fr. ; Kalkerde, Ger.) commonly 

 denotes lime, in any form ; but, properly speaking, it is pure lime. This term is fre- 

 quently applied to marl, and to earths containing a considerable quantity of lime. 



CALCAREOUS SPAR. Crystallised native carbonate of lime, of which there 

 are many varieties. 



Carbonic acid 44-0, lime 56'0, may be regarded as the usual composition of calc 

 spar ; it often contains impurities upon which depend the colours assumed by the 

 crystal. The carbonates of lime are extensively distributed in nature, as marbles, 

 chalk, &c. See ICELAND SPAR, MARBLE, &c. 



CALCAREOUS TUFA. This term is applied to varieties of carbonates of lime, 

 formed by the evaporation of water containing that mineral in solution. 



It is formed in fissures and caves in limestone rocks, about the borders of lakes, and 

 . near springs, tho waters of which are impregnated with lime. In the latter cases it is 



