CH A 



CH A 



horizontal, and not vertical, as in true 

 fishes. 



CETIC ACID {cete, a whale). An acid 

 procured from spermaceti, consisting of 

 margarine and fatty matter. Cetine is a 

 white laminated substance, constituting 

 pure spermaceti. 



CETONIA'D^. A family of Coleo- 

 pterous insects, of the section Melitophili 

 of Latreille, named from the genus ceto- 

 nia, of which the common rose beetle 

 affords a good example, and presenting 

 one of the most extensive as well as the 

 most brilliant of the beetle tribes. 



CETUS. The Whale ; a southern con- 

 stellation, containing ninety-seven stars, 

 the principal of which is Menkar. 



CETYL. The supposed radical of a 

 series of compounds derived from sperma- 

 ceti. 



CEVA'DIC ACID. Sabadillic acid. 

 A crystalline fatty acid, obtained by 

 saponification of the oil of cebadilla, or 

 the seeds of the Asagrcea officinalis. 



CEY'LANITE. A mineral found in 

 Ceylon, termed by Haiiy, pleonaste. 



CHA'BASITE. A mineral found in 

 the fissures of some trap rocks, and in 

 the hollows of certain geodes disseminated 

 in the same rocks. 



CHAFF OF RECEPTACLE. A term 

 popularly applied to the paleae, or the 

 membranous, colourless bracts, placed 

 between the florets upon the receptacle 

 of Compositae. 



CH ALA'ZA (xaXa^a, a small swelling). 

 A small brown spot observed at the apex 

 of some seeds, as of the Orange, formed 

 by the union of certain vessels proceeding 

 from the hilum. 



CHALCE'DONY. A silicious simple 

 mineral, uncrystallized, entering into the 

 composition of agates, and found at Chal- 

 cedon in Bithynia. It is of a uniform 

 milky white or pale yellow colour, often 

 with a wavy internal structure, and a 

 peculiar mammillary surface. 



CHALCI'DID^. AfamilyofHymeno- 

 pterous insects, of the section Pupivora 

 of Latreille, named from the genus chal- 

 ets, and characterized by minuteness of 

 size, brilliancy of colours, and the general 

 absence of nervures from the wings. 



CHALK. Carbonate of lime. In Geo- 

 logy, a rock which forms the higher 

 part of the cretaceous group. 



CHALYBEATE WATERS. Ferru- 

 ginous waters. Mineral waters, whose 

 predominating or active principle is iron. 

 There are two kinds: the carbonated, 

 containing carbonate of the protoxide of 

 74 



iron ; and the sulphated, containing sul- 

 phate of iron. Some of the latter con- 

 tain sulphate of alumina, and are called 

 aluminous sulphated chalybeate^. * 



CHAMA'CE^. Clamp-shells ; an or- 

 der of the conchiferous Mollusca, named 

 from the chama ; in these, the mantle is 

 closed, with the exception of three aper- 

 tures, two of which are for the ingress 

 and egress of water, and the third for the 

 passage of the foot, which is here usually 

 more powerful. 



CHAMiE'LEON. A modem southern 

 constellation, consisting of ten stars. 



CHAMiE'LEO'NID^. The Chame- 

 leon tribe ; a family of Saurian reptiles, 

 characterized by their extraordinary 

 length of tongue, and by the adaptation 

 of their feet and tail for climbing. 



CHAMBERED. Divided internally 

 into chambers or compartments, as the 

 testaceous cephalopods, or the nautilus. 



CHAMELEON MINERAL. A com- 

 bination of black oxide of manganese 

 and potash, which gives a green colour 

 to water, passes gradually through all the 

 shades of the prism, and at last becomes 

 colourless. 



CHA'MID^. A family of macrotra- 

 chian Bivalves, named from the typical 

 genus chama; in these animals the 

 length of the siphons, which charac- 

 terizes the tribe, is much reduced. 



CHARA'CE^. A small family of 

 cryptogam ous plants, consisting of the 

 two genera chara and nitella. These are 

 submerged aquatic plants, interesting to 

 the physiologist, as displaying the special 

 circulation, or cyclosis, in vegetables. 



CHARADRI'ADiE [charadrius, the 

 plover). The Plover tribe; a family of 

 the Grallatores, or Wading birds, in 

 which the bill is of moderate size, and 

 the hinder toe either entirely deficient, 

 or not long enough to reach the ground. 



CHARCOAL*. The residue of animal, 

 vegetable, and many mineral substances, 

 when heated to redness in close vessels. 



CHARLES'S WAIN. Seven con- 

 spicuous stars in Ursa Major or the 

 Great Bear. 



CHART {charta, paper). A geographi- 

 cal or nautical representation of a portion 

 of the earth's surface on paper, according 

 to a scale which regulates the relative 

 proportion of the parts. Geographical 

 charts, being of a general character, are 

 commonly called maps; but nautical or 

 marine charts are particularly devoted to 

 delineations of a coast and part of the 

 adjacent sea. 



