I S T 



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K A R 



have grouped them into bands or zones. 

 Humboldt has divided the northern 

 hemisphere into six isothermal zones or 

 bands. 



ISTIU'RUS. A genus of that family of 

 saurian s called iguanida, and thus named 

 by Cuvier. The distinguishing character 

 of the genus Istiurus is an elevated and 

 trenchant crest, extending along a por- 

 tion of the tail, and supported by spinous 

 apophyses of the vertebrae. 



FT us. The termination of adjectives in 

 itus shows merely the existence of some- 

 thing in general, as, for example, aitritus, 

 furnished with ears. 



JU'GULAR. (from jugulum, It&t.jugulaire, 

 Fr. giugtdare, It.) Pertaining to the 

 throat ; belonging to the neck. 



1. In botany, a catkin ; a species of in- 

 florescence consisting of chaffy scales 

 arranged along a stalk ; they are worm- 

 like tufts, which at the beginning of the 

 year grow out, and hang pendular down 

 from the hazle, walnut, filberd, &c. 



2. In zoology, a genus of insects of the 

 order Aptera. The feet are very nu- 

 merous, being on each side twice as many 

 as the segments of the body ; the an- 

 tennae are moniliform ; there are two 

 articulated palpi ; and the body is of a 

 semicylindrical form. There are many 

 species. 



I'VORY. (ebur, Lat. ivoire, Fr. avorio, It.) 

 A hard, solid, and firm substance, of a 

 white colour, and capable of a very good 

 polish. It is the tusk of the elephant. 

 The ivory from Ceylon is more valuable 

 than any other, from its not becoming 

 yellow in the wearing, as nearly all other 

 ivory does. 



JU'RA LIMESTONE, (calcaire de Jura, Jura 

 kalJc.) The name given by some con- 

 tinental geologists to that group of rocks 

 comprised in the oolite. The Jura lime- 

 stone group is composed of limestones of 

 various qualities, clays, sands, and sand- 

 stone, and contains the same fossils as 

 those found in the oolitic group of Eng- 

 land. In the range of the Jura and the 

 outer ranges of the Alps, the calcareous 

 formations are of such immense magni- 

 tude, and the beds are often so highly 

 indurated and crystalline, that it is only 

 from their relative position and imbedded 

 fossils, that we can trace their analogy to 

 the English strata. 



I/us. The termination of adjectives in ius 

 expresses the uses or aptness of an 

 organ ; for example, raptorius, adapted 

 to seize prey ; fossorius, fitted for digging ; 

 nutatorius, suited to swim, &c. 



JU'XTA-POSI'TION. (juxta- position, Fr. 

 juxta and positio, Lat.) The state of 

 being placed in nearness or contiguity ; 

 apposition. 



K 



KANGAROO'. An animal of the genus di- 

 delphys, the Didelphys gigantea of Lin- 

 nseus. It is a native of New Holland. 

 When of full growth it attains the size of 

 a large sheep. The fore-legs are short, 

 the hind legs of considerable length, so 

 that it advances by leaping rather than 

 walking or running. 



KA'OLIN. (The Porzellan Erde of Werner ; 

 the Argile Kaolin of Brongniart ; and 

 Feldspath decompose of Haiiy.) Porce- 

 lain clay. The name of an earth which 

 is used as one of the two ingredients in 

 the manufacture of oriental porcelain. 

 Mr. Bakewell observes, " I believe it is 

 the soft earthy granite from the moun- 

 tains of Auvergne which supplies the 

 kaolin used in the porcelain manufacture 

 at Sevres. Mons. Brongniart shewed me 

 a specimen of their best kaolin : it con- 

 tained crystals of pinite." M. Bromare 

 says that by analysing some Chinese 

 kaolin, he found it was a compound earth, 

 consisting of clay, to which it owed its 

 tenacity ; of calcareous earth ; of spark- 



ling crystals of mica ; and of small quartz 

 crystals. He says that he has found a 

 similar earth upon a stratum of granite., 

 and conjectures that it may be a decom- 

 posed granite. The kaolin used in most 

 countries for the manufacture of fine por- 

 celain or china, is generally produced 

 from the felspar of decomposing granite, 

 in which the cause of decay is the disso- 

 lution and separation of the alkaline in- 

 gredients. Cleveland says, " Kaolin is 

 essentially composed of silex and alu- 

 mine ; the proportions are variable, but 

 the silex usually predominates. When 

 pure kaolin is employed in the manu- 

 facture of porcelain, some ingredient must 

 be added as a flux, as, when pure, it is in- 

 fusible. There is satisfactory evidence 

 that kaolin has in most cases, if not in all, 

 originated from the decomposition of 

 rocks abounding in felspar, more par- 

 ticularly from graphic granite, which 

 consists almost entirely of quartz and 

 felspar. 

 KA'RPHOLITE. (from fcap^og and Xi'0o, 



