ARB 



ARC 



tbese diminutive adventurers ascend the 

 air, and contribute to fill it with that infi- 

 nity of floating 1 cobwebs which are so pe- 

 culiarly conspicuous at that period of the 

 year. When inclined to make these aerial 

 excursions, the spider ascends some slight 

 eminence, as the top of a wall, or the 

 branch of a tree ; and turning itself with 

 its head towards the wind, ejaculates 

 several threads, and rising from its sta- 

 tion, commits itself to the gale, and is 

 thus carried far beyond the height of the 

 loftiest towers, and enjoys the pleasure 

 of a clearer atmosphere. During their 

 flight it is probable that spiders employ 

 themselves in catching such minute wing- 

 ed insects as may happen to occur in their 

 progress ; and when satisfied with their 

 journey and their prey, they suffer them- 

 selves to fall, by contracting their limbs, 

 and gradually disengaging themselves 

 from the thread which supports them. 

 See Plate I. Entomology, fig. 7 and 8. 



ARAUCAR1A, in botany, a genus of 

 the Dioecia Monadelphia class and order. 

 Male, calyx scales of an ament, terminated 

 by a leaflet ; no corol. ; antherae 10 to 

 12, without filaments. Female calyx, an 

 ament with many germs ; no corol ; stig- 

 ma two-valved, unequal ; seeds numer- 

 ous, in a roundish cone. 



ARBITER, in civil law, a judge nomi- 

 nated by the magistrate, or chosen volun- 

 tarily by two parties, in order to decide 

 their differences according to law. 



The civilians make this difference be- 

 tween arbiter and arbitrator ; though 

 both ground their power on the compro- 

 mise of the parties, yet their liberty is dif- 

 ferent, for an arbiter is to judge accord- 

 ing to the usages of the law, but the arbi- 

 trator is permitted to use his own discre- 

 t ion, and accommodate the difference in 

 the manner that appears to him most just 

 and equitable. 



ARBITRATION, a power given by two 

 or more contending parties to some per- 

 son or persons to determine the dispute 

 between them ; if the two do not agree, it 

 is usual to add, that another person be 

 called as umpire, to whose sole judgment 

 it is then referred. The submission to 

 arbitration is the authority given by the 

 parties in controversy to the arbitrators, 

 to determine and end their grievances ; 

 and this being a contract or agreement, 

 must not be strictly taken, but largely, 

 according to the intent of the parties 

 submitted. There are five things incident 

 to an arbitration : 1. Matter of controver- 

 sy. 2. Submission. 3. Parties to the sub- 

 mission. 4. Arbitrators. 5. Giving up the 



VOL. I 



arbitration. Matters relating to a free- 

 hold, debts due on bond, and criminal of- 

 fences, are not to be arbitrated. 



ARBITRATOR, a private extraordina- 

 ry judge, chosen by the mutual consent 

 of parties, to determine controversies be- 

 tween them. Arbitrators are to award 

 what is equal between both parties, and 

 the performance must be lawful and pos- 

 sible. An action of debt may be brought 

 for money adjudged to be paid by arbitra- 

 tors. 



ARBOR Dia-iue. See CHEMISTRT. 



ARBOR vitx. See THUJA. 



AHBOR, in mechanics, the principal 

 part of a machine which serves to sustain 

 the rest ; also the axis or spindle on 

 which a machine turns, as the arbor of a 

 crane, windmill. &c. 



ARBUTUS, the strawberry-tree, in bo, 

 tany, a genus of the Decandria Monogynia 

 class of plants, the calyx of which is a 

 very small, obtuse, permanent perianthi- 

 um, divided into five segments ; the corol- 

 la consists of a single oval petal, divided 

 also into five segments; the fruit is a round- 

 ish berry, containing five cells, and small 

 osseous seeds. There are ten species. 



ARC concentric, is that which has the 

 same centre with another arc. 



ARC diurnal, that part of a circle de- 

 scribed by a heavenly body between its 

 rising and setting- ; as the nocturnal arc is 

 that described between its setting and 

 rising-: both these together are always 

 equal. 



ARCS equal, those which contain the 

 same number of degrees, and whose radii 

 are equal. 



ARCA, in natural history, a genus of 

 worms of the order Testacea ; animal a 

 tethys; shell bivalve, equivalve ; hinge 

 with numerous sharp teeth, alternately 

 inserted between each other. There are, 

 according to Gmelin, 43 species ; but they 

 are separated into four divisions, viz. A. 

 margin very entire, beaks recurved ; B. 

 margin entire, beaks inflected; C. margin 

 crenate, beaks recurved; D. margin cre- 

 nate, beaks inflected : of the latter we shall 

 notice A. nucleus ; shell obliquely ovate, 

 smoothish, with a triangular hinge .- in- 

 habits European geas, and is sometimes 

 found fossile, the size of a hazel nut, cov- 

 ered with an olivaceous skin, under which, 

 it is white, within silvery; shell unequally 

 triangular, with very fine perpendicular 

 striae, crossed by a few arched transverse 

 ones; depression behind the beak heart- 

 shaped. 



Of the division C. is the A. antiquata, 

 which occurs frequently on the coast of 



