816 COAL 



CXiOTH MAOTTT ACTOTUB AND DRESSING. See WOOLLEN and WOOL. 



CLOUDY CHALCEDONY. Chalcedony displaying cloudy spots in a pale 

 grey, semi-transparent base. 



CLOVER. Fodder plants belonging to the genus Trifolium. The common red 

 clover is Trifolium pratense. The white or Dutch clover T. repens. The shamrock 

 is generally considered as a species of Trefoil. 



CXiOVB, THE. (Clou, Fr. ; Clavo, Span.) The clove tree, Carophyllus aromaticus, 

 is a small tree, from fifteen to thirty feet high, a native of the Moluccas. The flowers 

 are odorous, and the bark, fruit, leaves, and roots are all more or less aromatic. 

 The flower buds are the cloves of commerce ; when prepared they have the appear- 

 ance of a nail, hence their name from clavo, a nail. The buds as soon as they are 

 gathered are dried in smoke over a fire, in the sun, or in a kiln. They are exported 

 in small boxes. 



The clove trade -was at one time the monopoly of the Dutch. The clove tree is, 

 however, now cultivated both in the East and West Indies, but the finest are still 

 brought from Amboyna in the Moluccas. 



CLOVE Oil.. Eugenic acid, or Carophyllic acid. C 2 H 12 4 (C 10 H 12 O a ). When 

 cloves are distilled with water, a large quantity of oil passes over. It has been 

 examined by Dumas, Ettling, Bockmann, Stenhouse, Calvi, and, more recently, by 

 Greville Williams. Treated with solution of potash, the greater portion dissolves, 

 leaving a small quantity of a hydrocarbon isomeric with oil of turpentine. See 

 CABBUBETTED HYDBOGEN. The potash solution, on being supersaturated with a 

 mineral acid, allows the eugenic acid to rise to the surface in the form of an oil. 

 When freshly distilled it is colourless, and boils at 438 S. Its density at 57'2 F. is 

 1-0684. On analysis it gave : 



Grevillo Williams Calculation 



Carbon . . 73'1 73-1 . . C 20 120 73-17 

 Hydrogen. . 77 7'6 . . H 12 7'32 

 Oxygen . . 19-2 19-3 . . 32 19'51 



100-0 100-0 100-00 



The density of its vapour was found to be 5-86; theory requires 5'67. The 

 above results were confirmed by a determination of the percentage of baryta in the 

 eugenate. C. G. W. 



CLOVES. The new bulbs produced from the subterranean axis of the hyacinth, 

 lily, onion, and the like. 



CLUTHALITE. A mineral which occurs in the amygdaloid rocks of Kilpatrick 

 Hills. It is found in flesh-red vitreous crystals, and consists of silica, alumina, iron, 

 and soda. It takes its name from Clutha, the name sometimes given to the valley of 

 the Clyde. 



CO All. (Houille, Fr. ; StdnJcohk, Ger.) Coal is a mineral of vegetable origin. 

 There is abundant evidence to prove this, but there still exists considerable uncer- 

 tainty as to the mode of conversion and as to the conditions under which our coal- 

 beds were formed. This is not the place for the discussion of these questions ; but it 

 appears necessary that the hypotheses of the best authorities on the subject should be 

 briefly given. 



' The occurrence of vegetable remains in all kinds of coal is such convincing 

 evidence of its formation from vegetable substances, that all further proof is super- 

 fluous.' Gustav Bischof. 



' There are few varieties of coal in which their vegetable origin can be detected by 

 anatomical examination.' Goppert. 



' It appears from the researches of Liebig, and other eminent chemists, that when 

 wood and vegetable matter are buried in the earth, exposed to moisture, and partially 

 or entirely excluded from the air, they decompose slowly, and evolve carbonic acid 

 gas, thus parting -with a portion of their original oxygen. By this means they 

 become gradually converted into lignite or wood-coal, which contains a larger portion 

 of hydrogen than -wood does. A continuation of decomposition changes this lignite 

 into common or bituminous coal, chiefly by the discharge of carburetted hydrogen 

 or the gas by which we illuminate our streets and houses, According to Bischof, 

 the inflammable gases which are always escaping from mineral coal, and are so often 

 the cause of fatal accidents in mines, always- contain carbonic acid, carburetted 

 hydrogen, nitrogen, and plefiant gas. The disengagement of all these gradually trans- 

 forms ordinary or bituminous coal into anthracite, to which the names of splint coal, 

 glance coal, hard coal, culm, and many others have been* given.' Lyell. 



