JUN 
botanical writers, says Dr. Sniitb, have 
judiciously preserved this very natural 
genus entire, notwithstanding the capsule is 
in some species one-celled, in others three- 
celled. The sea-rushes are planted on the 
sea-hanks in Holland : the roots running 
<leep into the sand, and matting very much 
so as to hold it together. In the summer, 
when they are full grown, they cut them, 
and when dry work them into baskets. 
JUNGERMANNIA, in botany, so nam- 
ed from Louis Jungermanmis of Leipsic, 
Professor of Botany at Atortf, a genus of 
the Cryptogamia Algas, LimiEeus, class and 
order. Natural order of Hepatic;®, Jussieu. 
Thirty species of these mosses are arranged 
in five subdivisions, in the fourteenth edition 
of “ Systema Vegetabilium.” Dr. Withering 
has forty-eight species in the third edition 
of his “Arrangement of British Plants;” he 
says many of them are beautiful microscopic 
objects. 
JUNGIA, in botany, so named from 
Joachim Jungius, M. D. a genus of the 
Syngenesia Polygamia Segregata class and 
order. Natural order of Composite Oppo- 
sitifolia?. Cinarocephalae, Jussieu. Essen- 
tial character : calyx common, three-flower- 
ed ; receptacle chafty ; florets tubular, two- 
lipped; outer lip ligulate ; inner two-part- 
ed. There is but one species, viz. J. ferru- 
ginea, the stems of whicli are woody, cover- 
ed with a ferruginous down ; leaves alter- 
nate, five-lobed, cordate at tlie base ; lobes 
rounded, blunt ; they are hirsute, and 
underneath hoary-; panicle terminating, 
large, decompounded ; heads of flowers 
small, heaped. It is a native of South 
America. 
JUNIPERUS, in botany, juniper-tree, a 
genus of the Dioecia Mouadelphia class and 
order. Natin-al order of Conifer®. Essen- 
tial character; male, calyx of the ament a 
scale; corolla none; stamina three: female 
calyx three-parted; petals three; styles 
three; berry three-seeded, irregular, with 
the three tubercles of the calyx. There are 
twelve species; some of these are lofty 
handsome trees ; but the J. communis, com- 
mon juniper, is a tow shrub, seldom more 
than three feet in height, sending out rhary 
spreading tough branches, inclining on 
every side, covered with a brown or reddisJi 
bark, with a tinge of purple. The male 
Rowers are sometimes on the same plant 
with the females, but at a distance from 
them ; they are commonly on distinct 
plants. The female flowers are succeeded 
by roundish berries, which are at first 
JUP 
green, and when ripe are of a dark purple 
colour. They continue on Uie bush two 
years, and are se.ssile in the axil of the 
leaves. Juniper is common in all the nor- 
thern parts of Europe, in fertile or barren 
soils, on hills or in valleys, in open sandy 
plains, or in moist and close wo6ds. In 
England it is found chiefly on open downs, 
in a chalky or .sandy soil. 
IVORY, a hard, solid, and firm sub- 
stance, of a while coloiir, and capable of a 
very good polish. It is the tusk of the ele- 
phant, and is hollow from the base to a cer- 
tain height. It is brought to us from the 
East Indies, and from the coast of Guinea. 
Tusks are valuable in proportion to their 
size; and it is observed, that the Ceylon 
ivory, and that from the island of Achem, 
do not become yellow by wear, as all other 
ivory does; hence tlie teeth of these places 
bear a larger price than those of the coast 
of Guinea. 
Ivory black, is prepared from ivory, or 
bones burnt in a close vessel. This, wdien 
finely ground, forms a more beautifid and 
deeper colour than lamp-black ; but, in the 
common methods of manufacturing, it is 
apt to be adulterated with charcoal dust, so 
as to be almost, or altogether, unfit for 
use. 
JUPITER, 11, in astronomy, one of the 
superior planets, remarkable for its great 
brightness. See Astronomy. 
Jupiter is the brightest of all the planets 
except Venus. He moves from west to 
east in a period of 4332 days, exhibiting 
irregularities similar to those of IVIars. Be- 
fore he comes into opposition, and when 
distant from the sun about 115°, his motion 
becomes retrograde, and increases in swift- 
ness till he comes into opposition. The 
motion then becomes gradually slower, and 
becomes direct when the planet advances 
within 116° of the sun. The duration of 
the retrograde motion is about 121 days, 
and the arch of retrogradation described 
is about 10°. But there is a considerable 
difference both in the amount and in the 
duration of this retrograde motion. 
Jupiter has the same general appearance 
with Mars, only that the belts on his sur- 
face are much larger and more permanent. 
They are said to have been first discovered 
by Fontana and two other Italians; but 
Cassini was the first who gave a good ac- 
count of them. Their number is very 
vaiiable, as sometimes only one, and at 
others no fewer than eigiit, may be per- 
ceived. They are generally parallel to one 
