AR A

201

AR A

quosa order, and tetradynamia class of plants; natural order, Sili-quosa?. Calyx closed, two of the leaves gibbous below; nectari-ferous glands four, on the inside of each leaf of the calyx. ThereRre twenty-one species chiefly American.

ARABLE Land , anciently Aralia, [from ararc to plow,]land for tillage, or ploughing. See Husbandry.

ARABS, vVandkring. See Bedouins .

ARACAN, a small kingdom, N. E. of the bay of Bengal. Ithas the couveniency of a spacious river, and a harbour largeenough to hold all the ships in Europe . Elephants and buffaloesare very numerous here, and are made use of instead of horses.They have, plenty of provisions, but little trade.

Aracan, the capital of Aracan. Lon. 93. 10. E. Lat.20. 38. N.

ARACHIS, a genus of the diadelphia order, and decandriaclass of plants; natural order, Papilionacie. Calyx two-lipped;corolla reversed ; filaments united; legume gibbous, coriaceous,swelling at the seeds. It has one species, a native of India .

ARACHNE , in fabulous history, a young maid of Lydia, thedaughter of Idmon, said to have been the inventress of spinning.She is fabled to have been so skilful in this art, as to have chal-lenged Minerva at it, who tore her work, and struck her; whichdisgrace driving her to despair, she hanged herself. Minerva,from compassion, brought her to life, and transformed her into aspider, which still employs itself in spinning.

ARACIiNOIDES, [from a spider, and ui®', form,]

1. One of the tunics of the eye, so called from its resemblanceto a cobweb. 2. A tine thin transparent membrane, which, lyingbetween the dura and the pia mater, is supposed to invest thewhole substance of the brain. 3. An appellation given to one ofthecoverings of the spinal marrow. See Anatomy.

Aracnoides, one of the genera of the echini marini; the dis-tinguishing characters of which are, that it is of a circular cir-cumference, but variously broken in at the edges. See Echinusand Plate V.

ARACK, a spirituous liquor distilled from rice, and drunk inIndia , as we do brandy and other liquors in this country.

ARACTHUS, a river of ancient Epirus, now r called Spag-magmurisi.

ARAD , in ancient geography, a city of Arabia Petraia, twentymiles from Hebron. The Israelites , having departed from Se-pher, came to Arad , and from thence to Makkelath.

Arad, a district and town of Hungary .

A R TO METER, [from ajato;, thin, and 'xe7jov, measure,] an in-strument wherewith to measure the density or gravity of fluids.The ara'ometer, or water-poise, is usually made of glass ; consistingof a round hollow ball, which terminates in a long slender neck her-metically 7 sealed at top ; there being lirst as much running mer-cury put into it as will serve to balance or keep it swimming in anerect position. The stem is divided into degrees, to shew by thedepth of its descent into any liquor, the lightness of it: for thatfluid in which it sinks least must be the heaviest; and that inwhich it sinks lowest, lightest. See Hydrometer.

AR/EOMETRY,the science of measuring the density of fluids.

ARTDTICS. See Areotics.

ARAEAH, the ninth day of the last month of the Arabic year,named Dhoulhegiat; on which the pilgrims of Mecca performtheir devotions on the mountain Arafat.

ARAFAT, orGiBEL el Akafat, the mountain of knowledge,a mountain in Arabia, near Mecca .

ARAGONA, a principality of Italy , in the Val di Mazara,belonging to Sicily .

ARAHCM, or HARAIHJM, in ancient writers, denotes aplace consecrated or set apart for holy purposes.

ARAL, a great lake lying a little eastward of the Caspian sea.Length nearly 300 miles, and breadth about 150. It is surprisingthat this lake should be quite unknown to geographers, till withinthese few years,

ARALfA, in ancient law writers, arable lands. They are alsodenominated aratoria, and aiaturia.

Aralia, the Angf.lica Tree ; a genus of the pentagvniaorder, and pentandria class of plants; and in the natural order,Hederacea?. The essential characters are: involucrum an um-bella; calyx quinquedentated; petals five; berry five-celled;seeds solitary, hard, oblong. There are ten species, natives of theIndies.

VOL. i.—xo. 53.

ARAM, or the ARAM.EAN REGION, in ancient geogra-phy, the Hebrew name of Syria , so called from the son of Shem.

Aram-Soba, or Aram-Zobah, a country conquered by David,situated where Palmyra afterwards stood.

ARANDA-DE-DUERO , a town of Old Castile, 22 miles, E.of Valladolid . Lon. 3. 30. W. Lat. 41. 40. N.

ARANEA, in entomology 7 , the Spider ; a genus of insects,order aptera, or insects without wings; legs eight, with threejoints in each and terminating in three crooked claws ; eves eight,or six. In the fore part of the head, at the mouth, there is a pairof sharp crooked claws or forceps, which stand horizontally 7 , and,when not exerted for use, are concealed in two cases contrivedfor their reception. These claws are the weapons with whichthey kill flies, &c. for their food. The belly or hinder part isseparated from the head and breast by a small thread-like tube.The skin or outer surface is a hard polished crust. Spiders fre-quently cast their skins, which may be found in the webs perfectlydry and transparent; and from such skins the forceps, or claws,for they are always shed with the skins, may easily be separated,and examined with much greater exactness, than in the commonspider while living. Spiders have live tubercles or nipples at theextremity of the bellv, whose apertures they can enlarge or con-tract at pleasure. It is through these apertures that they spin agluey substance of which their bellies are full. They fix the endof their threads by applying these nipples to any substance,and then receding from it. They can stop the issuing of thethreads by contracting the nipples, and reascend by means of theclaws on their feet. The darting out of long threads, which hasbeen observed by naturalists, and by means of which some speciesof spiders can convey themselves to great distances, deserves par-ticular notice. Dr. Lister tells us, that attending closely to aspider weaving a net, he. observed it suddenly to desist in the mid-work: and turning its tail to the wind, it darted out a thread withthe violence and stream we see water spout out of a jet: thisthread, taken up by the wind, was immediately carried to somefathoms long; still issuing out of the belly of the animal. By-and-by the spider leaped into the ait, and the thread mounted her upswiftly. After this discovery, he made the like observation onnear thirty different species of spiders; and found the air tilledwith young and old, sailing on their threads, and doubtless seizinggnats and other insects in their passage, there being often manifestsigns of slaughter, legs and wings of flies, &c. on these threads, aswell as in tneir webs below. Dr. Hulse discovered the samething about the same time. It is scarcely credible to what heightthey will mount; which yet is precisely true, and a thing easilyto be observed by one that shall fix his eye some time on anypart of the heavens, the white webs, at a vast distance, very dis-tinctly appearing from the azure sky : but this is in autumn only,and that in very fair and calm weather. In a letter to Mr. Ray,dated January 1670, speaking of the height to which spiders areable to fly he says; “ Last October, &c. I took notice, that theair was very full of webs: I forthwith mounted to the top of thehighest steple on the Minister (in York,) and could there discernthem yet exceeding high above me.” He further observes, thatthey not only thus shoot their threads upwards, and mount withit in a line almost perpendicular; they also project them in a lineparallel to the horizon, as may be seen by their threads runningfrom one wall to another in a house, or from one tree to anotherin the field, and even from wall to wall across gardens of consider-able extent. The matter of which the spiders’ threads are formed,is a viscid juice, elaborated in the body of the animal, and emittedfrom papilla: situated at the extremity of the belly ; which are hu»nished with numerous apertures that do the business ot wire-drawers, as it were, in forming the threads. Of these aperturesM. Reaumur observes, there are enough in the compass of thesmallest pin’s head to yield a prodigious quantity of distinctthreads. The holes are perceived by their effects: take a largegarden spider ready to lay its eggs, and applying the ringer ona part of its papilla 7 , as you withdraw that linger it will take wiihit an amazing number of different threads. M. Reaumur lias of-ten counted' seventy or eighty with a microscope, but has per-ceived that there were infinitely more than he could tell. Ineffect, if he should say that each tip of a papilla furnished a thou-sand, he is persuaded he would say far too little. Such is the te-nuity of the threads in the larger sort of spiders. But if we ex-amine the young produced by those, we shall rind that the), no3 F sonnet