25 O O 
ZOO 
Z O N 
it melts into a transparent glass. Infusible 
| with fixed alkali and microcosinic salt. 
1 . The vairietv formerly called hyacinth is 
of a yellowishi-red colour, mixed with brown. 
Its surface is smooth. Its lustre 3. Its trans- 
parency 3 to 4. 
2. 'I'iie variety formerly called jargon of 
[ Ceylon is eiither grey, greenish, yellowish 
brown, reddiish brown, or violet. It has lit- 
tle external lustre. It is sometimes nearly 
opaque. 
The first variety , according to the analysis 
I of Vauquelim, is composed of 
04.5 zirconia 
32.0 silica 
2.0 oxide of iron 
98.5 
ZIZANIA, a genus of plants of the class 
moncecia, order hexandria ; and in the natu- 
ral system arranged under the 4th order, 
gramina. There is no male calyx; the co- 
rolla is a biivalved beardless glume, inter- 
mixed with the female flowers; there is no 
female caly:x ; the corolla is an univalvedj 
cucullated, and aristated glume ; the style is 
bipartite, and there is one seed covered with 
the plaited corolla. There are 2 species ; 
the aquaticai and terrestris, none of which 
are natives of Britain. 
ZODIAC’, See Astronomy. 
ZODIAC AL light, a brightness sometimes 
observed in tthe zodiac, resembling that of the 
galaxy, or nnilky way. It appears at certain 
; seasons, viz. towards the end of winter and in 
spring after sun-set, or before his rising in au- 
tumn and beginning of winter, resembling the 
form of a pyramid, lying lengthways with its 
axis along tine zodiac, its base being placed 
obliquely witth respect to the horizon. This 
phenomenon! was first described and named 
by the elder Cassini, in 1683. It was after- 
wards observed by Fatio, in 1684, 1685, and 
1686; also Iby Kirch and Eimmart, in 1688, 
1689, 1691, 1693, and 1694. 
ZOEGA, a genus of plants of the class 
syngenesia, and order polygamia frustranea. 
The receptaicle is bristly ; the pappus seta- 
ceous ; the icorullulae of the radius ligulated ; 
the calyx imibricated. There is one species, 
the leptaurea. 
ZONE, in geography and astronomy, a 
division of the terraqueous globe, with respect 
i: to the differ ent degree of heat found in the 
different parfts. 
A zone is the fifth part of the surface of 
the earth, contained between two parallels. 
The zones are denominated torrid, frigid 
; and tempera te. 
The torrid zone is a band surrounding the 
terraqueous globe, and terminated by 7 the 
two tropics. Its breadth is 46° 58h The equa- 
tor, running through the middle of it, divides 
it into two equal parts, each containing 23° 
29'. The amtients imagined the torrid zone 
uninbabitabhe. 
The temperate zones are two bands, en- 
vironing tine globe, and contained between 
! the tropics and the polar circles : the breadth 
of each is 43° 2'. 
The frigid zones are segments of the sur- 
! face of the earth, terminated, one by the an- 
tarctic, and the other by the arctic circle, 
f The breadth of each is 46° 58'. 
ZONITIS, a genus of insects of the order 
| coleoptera, The generic character is, an- 
I tennx testaceous ; feelers four, filiform ; jaw 
I 
entire, longer than the feelers ; lip emarginate. 
There are eight species. 
ZOOLOGY, is that part of natural his- 
tory which relates to animals. 
In order to abridge the study of zoology, 
many methods of reducing animals to classes, 
genera, and species, have been invented: but 
as that of Linnaeus is undoubtedly the best, 
the most extensive, and the most generally 7 
adopted, we shall give a brief account of 
it. 
Linnaeus divides the whole animal kingdom 
into six classes. The characters of these six 
classes are taken from the internal structure 
of animals, in the following manner: 
Class I. Mammalia , includes all animals 
that suckle their young. The characters of 
this class are these : The heart has two ven- 
tricles and two auricles; the blood is red and 
warm ; and the animals belonging to it are 
viviparous. 
Class II. Ares, or birds. The characters 
are the same with those of class I. excepting 
that the animals belonging to it are ovipa- 
rous. 
Class III. Amphibia, or amphibious ani- 
mals. The heart has but one ventricle and 
one auricle ; the blood is red and cold ; and 
the animals belonging to this class have the 
command of their lungs, so that the intervals 
between inspiration and exspiration are in 
some measure voluntary. 
Class IV. Pisces, or fishes. The heart 
has the same structure, and the blood the same 
qualities, with those of the amphibia; but the 
animals belonging to this class are easily dis- 
tinguished from the amphibia, by having no 
such voluntary command of their lungs, and 
by having external bran c hue or gills. 
Class V. Insecta, or insects. The heart 
has one ventricle, but no auricle ; the blood 
is cold and white ; and the animals are fur- 
nished with antennae or feelers. See Insect. 
Class VI. Vermes, or worms. The cha- 
racters are the same with those of class V. 
only the animals have no antennas, and are 
furnished with tentacula. 
The first class, Mammalia , is subdivided 
into seven orders; the characters which are 
taken from the number, structure, and situa- 
tion of the teeth. 
Order I. The primates have four incisores. 
or fore teeth, in each jaw, and one dog-tooth, 
N. B. By one dog-tooth, Linnaeus means one 
on each side of the fore-teeth in both jaws. 
This order includes four genera, viz. homo, 
simia, lemur, vespertilio. 
Order II. The brutahave no fore-teeth 
in either jaw. This order includes seven ge- 
nera, viz. rhinoceros, elephas, trichechus, 
bradypus, myrmecophaga, manis, dasypus. 
Order III. The ferae have, for the most 
part, six conical fore-teeth in each jaw. This 
order includes ten genera, viz. phoca, canis, 
felis, viverra, mustela, ursus, didelphis, talpa, 
sorex, erinaceus. 
Order I V. The glires have two fore-teeth 
in each jaw, and no dog-teeth. This order 
includes ten genera, viz. hystrix, lepus, castor, 
mus, sciurus, myoxus, cavia, arotomys, dy- 
pus, hyrox. 
Order V. The pecora have no fore-teeth 
in the upper jaw, but six or eight in the under 
jaw. This order includes eight genera, viz. 
camelus, moschus, giraffa, cervus, antilope, 
capra, ovis, bos. 
Order VI. The bellux have obtuse fore- 
6 A 2 
923 
teeth ill each jaw. This order includes 
four genera, viz. equus, hippopotamus, sus, 
tapir. 
Order VII. The cete, or whale kind, have 
no uniform character in their teeth, being 
very different in the different genera ; but are 
sufficiently distinguished from the other or- 
ders of mammalia, by living in the ocean, 
having pectoral fins, anda fistula or spiraculuin 
upon the head. This order includes four ge- 
nera, viz. menodon, balxna, pbyseter, delphi- 
nus. 
The generic characters of (he mammalia 
are, like those of the orders, almost entirely 
taken from the teeth, excepting the vesper- 
tilio, which, besides the character of the order 
derived from the teeth, has this farther mark, 
that there is a membrane attached to the feet 
and sides, by means of which the creature is 
enabled to fly: the hystrix, whose body 7 is 
covered with sharp spines : and the whole 
order of pecora, whose genera, besides the 
characters taken from the teeth, are distin- 
guished into those which have horns, those 
which have no horns, and by peculiarities in 
the horns themselves. 
The specific characters are very 7 various, 
being taken from any part of the body which 
possesses a peculiar uniform mark of distinc- 
tion. As examples of these characters are t* 
be found under the proper name of each ge- 
nus, it is unnecessary to say any thing further 
concerning them in this place. 
The second class, Ares, is subdivided into 
six orders ; the characters of which are taken 
chiefly from the structure of the bill. 
Order I. The accipitres have a hooked bill, 
the superior mandibule, near the base, being 
extended on each side beyond the inferior ; 
and in some it is armed with teeth. This or- 
der includes four species, viz. vultur, falco, 
strix, lanius. 
Order II. The picae have a convex, com- 
pressed bill, resembling a knife. This order 
contains 23 genera, viz. trochilus, certhia 
upupa, glaucopis, bwphaga, sitta, oriolus, co- 
racias, gracula, corvus, paradisea, ramphastos, 
trogon, psittacus, crotophaga, picus, yunx, 
cuculus, bucco, boceros, alcedo, merops, to- 
dus. 
Order III. The anseres have a smooth bill, 
broadest at the point, covered with a smooth 
skin, and furnished with teeth: the tongue is 
fleshy ; and the toes are palmated or webbed. 
This order includes 13 genera, viz. anas, mer- 
gus, phaeton, plotus, rhyncops, diomedea, ap- 
tenodyta, alca, procellaria, pelecanus, larus, 
sterna, colymbus. 
Order IV. The grallx have a somewhat cy- 
lindrical bill: the tail is short, and the thighs 
are naked. This order contains 20 genera, viz. 
phoenicopterus, platalea, palamedea, mycte- 
ria, tantalus, ardea, corrira, recurvi rostra, 
scoLopax, tringa, fulica, parra, rallus, vaginalis, 
psophia, cancroma, scopus, glareola, hxmato- 
pus, charadrius. 
Order V. The gallinx have a convex bill ; 
the superior mandible is vaulted over the in- 
ferior: the nostrils are half covered with a 
convex cartilaginous membrane : and the feet 
are divided, but connected, at the inmost 
joint. This order contains 10 genera, viz. 
struthio, didus, pavo, meleagris, penelope, 
crax, phasianus, numida, tetrao. 
Order VI. The passeres have a conical 
sharp pointed bill ; and the nostrils are oval, 
wide, and naked. This order contains 17 ge- 
