ARC 
formerly eftimated at 23° 30', but its mean quantity is now 
23 0 2%' nearly. This, and its oppofite, tlie antarblic cir¬ 
cle, are alfo called the polar circles, where the longed 
day and the longed night are twenty-four hours ; and with¬ 
in all the ipace of thefe circles, at one time of the year, 
the fun never lets, and at the oppofite feafon he never 
riles, for Come days, more or lefs according as the place is 
nearer the pole. 
Arctic Pole, the north pole of the world, and fo 
called from agyj©‘, urfa , the bear, from its proximity to 
the condellatiun of that name. 
ARC'TIUMj/lfa^T^, a bear.] The plant Burdock ; 
in botany, a genus of the clufs fyngenefia, order polygamia 
aequalis, ranking in the natural order of compofitae capi- 
tatae. The generic charabters are—Calyx : common glo¬ 
bular, imbricate ; fcales lanceolate, ending in long ftibu- 
late prickles, reflex and hooked at the end. Corolla t 
compound tubular, uniform; corollules hermaphrodite 
equal; proper monopetalous, tubular; tube (lender, 
long; limb ovate, qtiinquefid; divifions linear, equal. 
Stamina : filaments five, capillary, fliort, antherae cylin- 
dric, tubular, length of the corolla, five-toothed. Piftil- 
lum : germ oblong, with a villofe top ; dyle filiform, 
longer than the damens ; ftigmas bifid, reflex. Pericar- 
piuni : none ; calyx converging. Seeds: (olitary, verti¬ 
cally pyramidal, the two oppofite angles obliterated, gib¬ 
bous on the oittlide ; down fimple, (liorter than the feed. 
Receptaculum : chaffy, flat ; chaffs Cetaceous .—EJfential 
CharaEler. Calyx, globular; feales furnilhed at the end 
with indebted hooks. 
Species. 1. Arbtium lappa, or common burdock, burr, 
or clot-burr: leaves cordate, unarmed, petioled. Bur¬ 
dock is very common by road Tides, on rubbifh and on ditch 
banks throughout Europe, flowering in July and Augufl. 
A decobtion of the roots is efieemed by fome very emi¬ 
nent phylicians, as equal to that of farfaparilla. Two 
ounces of the dried root are boiled in three pints of water, 
till one pint is waded, and a pint or more of the drained 
liquor taken W3rm every day. The herb being burnt 
green, between the time of flowering and feeding, in a 
hole made in the ground, without fuBering the flame to 
efcape ; three pounds of the afhes produced produced fix- 
teen ounces of very white alkaline fait, as good as the bed 
potafh. There are many varieties of this common plant, 
differing in colour, and the (ize and fmoothnefs or vvoolli- 
nefs of the heads. Tlv. mod remarkable of thefe, is the 
arclium■tomentojum, or woolly-headed burdock, which Mil¬ 
ler has figured in his plaies, and looks upon as a diftinct 
fort. 
2. Arctium perfonata, or cut-leaved burdock : leaves 
decurrent ciliate-fpiny ; root-leaves pinnate ; fiem-leaves 
oblong ovate. Native of Swiflerland, Audria, Silefia, 
and Siberia ; flowering in July and Augufl. 
3. Arbtium carduelis.: leaves pinnatifid prickly. Na¬ 
tive of the mountains in Upper Carniola, and in Silefia. 
Propagation and Culture. Thefe plants may readily be 
increafed from feed, and are feldom admitted into any but 
botanic gardens. It is a troublefome weed ; but may be 
dedroyed with lefs trouble than fuch plants as have pe¬ 
rennial roots; if it be cut up before it feeds, in two or 
three years it will entirely dilappear. 
ARCTO'MYS, f. in zoology, the Marmot; a genus 
belonging to the order of glares, the charabters of which 
are :—Fore teeth wedged, two in each jaw : grinders up¬ 
per five each fide, lower four : clavicles perfebt. The 
head is gibbous and rounded; ears (hort ; body thick; 
tail (hort, hairy ; fore-feet four-toed, with a fliort thumb, 
hind-feet five.toed; caecum large. The animals of this 
genus become torpid in the winter, feed on grain and 
roots, and burrow in the ground. There are eleven fpecies 
now known, viz. 
1. Arbtomys inarmota, the Alpine marmot: ears (hort, 
round; body brown, beneath reddifti. Inhabits dry open 
places on the fummits of the Alps and the Pyrenean 
mountains ; feeds on roots, herbs, inlebts, and w hen tamed 
Vol. II. No. 62. 
A R C 120 
whatever is offered ; drinks little, bafks in the fun ; lives 
among fmall tribes, with a centinel placed to give notice 
of danger, which is done by a hifs ; forms a burrow with 
many chambers and entrances for the furamer, another 
lined with fott grafs in which it remains torpid during 
winter; eats with its fore-paws ; walks on its heels, often 
erebt ; is eafily caught when out of its burrow ; it can 
hardly be kept awake in winter even in warm chambers; 
it is gravid (even weeks, and brings from two to four young 
The flefli is tender; and the fat and (kin are tiled by the 
mountaineers for various remedies. 
2. Arbtomys monax, the Maryland marmot : ears fliort, 
round; fnout blueifli; tail long and hairy ; body grey. 
Inhabits the warm parts of North America, in holes of 
rocks, wintering under hollow trees; fize of a rabbit or 
hare; and the flelh good. 
3. Arbtomys bobac, the Chinefe marmot ; ears fmall ; 
tail hairy; (ore-thumb clawed ; body grey, beneath ye) 
lowifh. Inhabits the dry and funny mountains of Afia 
and China, in deep burrows; lives in families of twenty or 
twenty-four; goes abroad morning and mid-day, leaving 
a centinel at the entrance of its burrow'; feeds on vegeta¬ 
bles ; defends itfelf with its fore-paws; is eafily tamed; 
eats with its fore.feet ; in fummer voracious; deeps in 
winter ; the flefh is good ; and the fat is ufed for dreliing 
leather and furs. 
4. Arbtomys empetra, the Canadian marmot: ears 
fliort; tail hairy; body above mixed grey, beneath 
orange. Inhabits North America. 
5. Arbtomys pruinofa, the hoary marmot : ears fhort ; 
tail and feet black; hair of the back, (ides, ana belly, long, 
harfli, hoary. Inhabits North America ; and refembles 
the monax : is about the fize of a rabbit. 
6. Arbtomys fuflica, the Cafan marmot: ears very fliort; 
tail hairy and fliort ; body above yellowi(h brown, with 
many fmall white fpots. Inhabits Cafan and Audria, in 
holes on the declivities of mountains; burrows deep and 
winding, witii feveral entrances and many apartments, in 
which are (tored pulfe and corn ; (ize of a ferret. 
7. Arbtomys citillus, the earlefs marmot : tail very 
fliort; body cinereous; beautifully (potted with white oil 
the Tides ; a Break of white from the ears to the whilkers ; 
nofeblunt, and black. Inhabits Hungary, Audria, and 
Poland ; about a foot long. 
S. Arbtomys zemni, the Podolian marmot : ears fliort; 
body moufe-gre.y ; feet five-toed ; eyes minute, and al- 
moft concealed. Inhabits Ruflia, Poland, Perlia, and 
China ; is flrong and mifehievous. It varies in colour 
and fize, fometimes fpotted with white ; tail fometimes 
longifli, with the hair (tied like a fquirrel. 
9. Arbtomys guildi, the Barbary marmot: ears wide, 
open, and truncate ; body flame colour. Inhabits Bar¬ 
bary, near Mount Atlas ; (ize of a rabbit ; and burrows 
in long deep caves. 
10. Arbtomys Hudfonius, the taillefs marmot: ears 
fliort ; body brown-afli ; and only the rudiment of a tail. 
Inhabits Hud Ion’s Bay. 
11. Arbtomys maulinus, the Chilefe marmot: ears 
fluirp ; feet five-toed ; body reddifli-brown. Inhabits the 
woods of Chili ; two feet and a half long. 
ARCTO'PHYLAX,/’. [from agxlo{, bear, and tpvXarla, 
I guard.] In altronomy, the conflellation called Bootes. 
ARC'TOPUS, J. [agy.Tou Trove, bear’s foot.] I11 bota¬ 
ny, a genus of the cials polygamia, order dioecia, ranking 
in the natural order of umbellatse or umbelliferae. The 
generic charabters are—I. Male. Calyx : umbel univer¬ 
sal long, unequal ; partial (liorter, more abundant; invo- 
lucre univerfal five-leaved, (hort; partial five-leaved, the 
length of the umbeilule ; perianthium five-parted, very 
(mail. Corolla: univerfal, uniform ; proper petals five, 
entire, oblong. Stamina: filaments five, fetaceous, longer 
than the corolla; antherae fimple. Piftillum : germ none; 
(lyles two, fetaceous, longer than theftamens; ftigmas 
(imple. Pericarpium : abortive.—II. Female (or andro¬ 
gynous) on a diliinbt plant. Calyx ; umbel partial with 
L I feflile 
