ZO N 



754 



ZUM 



and X. hyacinth. Both are silicates of 

 irconia, coloured with oido of iron. It 

 possesses a double refrat tire power, by 

 which It In readily distinguished from 

 idocrase, garnet, and staurotide. 



ZiRCoS'iA. An earth which forms the 

 basis of zircon. It is a fine white pow- 

 der, without taste, or smell, and is inso- 

 luble in water ; yet, when slowly dried, 

 it coalesces into a semi-transparent yel- 

 lowish mass like gum-arabic, which re- 

 tains one-third its weight of water. In 

 chemical language it is an oxide of Zirco- 



ZIRCO'NICM. The metallic basis of 

 zirconia, discovered by Berzelius, in 

 1824. Zirconium, however, more resem- 

 bles charcoal-powder than a metallic 

 substance, and burns with almost explo- 

 sive violence. 



ZIZA'NIA. Canada rice. A genus of per- 

 ennial plants. JUoneecia Hexandria. Name 

 ggaM, the lolium of the Latins. The 

 grain of the Z. aquatica is valued. 



ZOAN'THUS. A genus of Polypi, of the 

 order Carnosi, sepaiated from the Actinse 

 by Cuvier. Name from aisv, an animal, 

 and avQo$, a flower; the animals being 

 united, in considerable numbers, on a 

 common base, and having a broad surface 

 like a flower. 



ZO'CLE. In architecture, a low square 

 member, used instead of a pedestal, to 

 support a column. The zocle differs from a 

 pedestal, in being without base or cornice. 



ZO'DIAC, Gr. J>S;axof,containingliving 

 creatures, from &uov, an animal. 1. I 

 astronomy, the tract of the sun through 



the twelve signs. 2. A broad circle of 



the sphere containing the twelve signs, the 

 middle of which is the ecliptic, from which 



the sun never deviates. 3. Two circles 



parallel to the ecliptic, which bound and 

 comprehend the excursions of the planets 

 north and south, never exceeding 20, 

 which is the utmost braadth of the zodiac 



ZODI'ACAL LIGHT. In meteorology, a 

 brightness sometimes perceived in the 

 heavens at certain times of the year, 

 after sunset and before sunrise ; supposed 

 to be an effect of the solar atmosphere. 



ZOI'SITE, } A variety of epidoteof a grey, 



ZOI'ZITB. j brown, or yellowish colour: 

 so named after Baron Von Zois. 



ZO'HAR, Heb. splendour. A Jewish book, 

 highly esteemed by the rabbis, and sup- 

 posed to be of great antiquity. 



ZONE, *vj. 1. A girdle. 2. In geo- 

 graphy, a division of the earth with respect 

 to the temperature of different latitudes. 

 Tke zones are five : the torrid zone (q. v.), 

 the two temperate ttones, situated between 

 the tropics and the polar circles ; and two 

 frigid zones, situated between the polar 

 circles and the poles. 



y.o'octsT, from * an animal, an4 

 ve"r/s, a cyst or budfnt. An arlroal, 

 formed of a membranous cyst, distended 

 with an aqueous fluid. 



"OOG'RAPHY, from 415?, an animal, and 

 y^ st^ea, to describe. Zoology. 



ZO'OLITE, from uo, an animal, and A/0s, 

 stone. A petrified animal. 



ZO'OLOGY, from ^ov, an animal, and 

 ^'ys. a discourse, i.e., the science of ani- 

 mals. This science, then, teaches the 

 nature and properties of animals, their 

 classification, their order of succession, 

 and their distribution over the earth. 



ZOON'IC ACID. Acetic acid combined 

 with animal matter, obtained by distilling 

 any animal substance. Berthollet gave it 

 this name, supposing he had discovered a 

 new acid. 



ZOON'OMY, *> and o,aof,law. The sci- 

 ence of the laws of animal life. 



ZOOPH'AGA, from uov> an animal, 'and 

 Payw, to eat. A name given to that tribe 

 of animals which attack living animals 

 and devour them. 



ZOOPB'ORUS. In architecture, a name 

 given by the Greeks to the frieze, because 

 it was in general covered with figures of 

 animals: 00*, an animal, and fsjai, to 

 bear. 



ZOOPH'YTA. Zoophytes. Radiated ani- 

 mals : ao$VTat, from oy, an animal, and 

 <pt/T, a plant. Animal-plants. These 

 names refer to a multitude of animals, 

 whose organization is always evidently 

 very simple; and, although they differ 

 widely among themselves, agree in one 

 point, viz., their parts are arranged on an 

 axis, and on one or several radii, or on 

 one or several lines extending from one 

 pole to the other. The classes of this 

 division are Echinodermata, Entozoa, 

 Acalepha, Polypi, and Infusoria. Zo- 

 ophytes are either free in the sea, or at- 

 tached for life to some substance. 



ZOOPHYTOI/OOY, from ai0ftiTw, zoophyte, 

 and \vyof, discourse. That branch of 

 natural history which treats of the struc- 

 ture, habits, &c., of zoophytes. 



ZOOT'OMY, from aw, an animal, and 

 rtu.yo, to cut. The dissection of animals. 

 ZORIL'LE, 1 A foetid animal of the weasel 

 ZORII.I/. ) tribe found in South Ame- 

 rica. The name is Spanish, Xoi-illo, th 

 cub of a fox. 



ZOS'TERA. The grass-wrack: a genus 

 of piperitae. Named from ^a/a-r,a girdle, 

 on account of the girdle-like appearance 

 of the leaves. 



ZOTHE'CA. A small apartment, separated 

 from a larger one by movable curtains- 



ZU'MIC, pertaining to leaven ; {iiu,*,, 

 ferment. The tumic acid is said to be 



