AXI 



113 



AZ1 



N amed in honour of an Arabian physician. 

 'Native of the hot parts of both Eastern 

 and Western continents. 



AVK/OLA, a genus of equivalve shell 

 with a rectilinear hinge : it belongs to 

 the oyster family, and is known popularly 

 as the Mother-of-pearl oyster. The 

 species which produces the tine pearls of 

 Ceylon is the Mytilut Margaritifrra, Lin. 



AVICC'LIDJE, a family of shell-flsh com- 

 prehending the muscles and pearl oysters. 

 Sicninson. 



AVOI'DANCE. In ecclesiastical law, sig- 

 nifies the condition of a benefice when 

 void of an incumbent, and is opposed to 

 plenarty. 



AVOIRDCPO'IS, FT. acoir dtipois, to hare 

 weight. The weight commonly used for 

 bulky and coarse commodities. The pound 

 contains 16 oz., and is to the troy pound 

 as 17 to 14. 



AVOSET'TA, the Avoset, a species of 

 grallae placed by Pennant among the 

 palmipedes. The bird is of the size of the 

 lapwing, and is common to Europe and 

 America. 



AVO'WRT, in laic, the act of the dis- 

 trainer of goods who in an action of re- 

 plevin avows and justifies the taking; the 

 act of maintaining the right to distrain. 



A- WEI OH, in nautical language, the 

 B&me with a-trip. 



AWL'WORT, the Subularia aquatica,a.n 

 indigenous aquatic perennial, so named 

 from its awl-shaped (subtilate) leaves. 



AWN'INO. 1. A covering of canvas ex- 

 tended over the decks of a ship to give 



shelter from the sun, rain or wind. 2. 



That part of the poop deck which is con- 

 tinued forward beyond the bulk head of 

 the cabin. 



AWXLESS, without awn or arista. 



AXA.TA'CAT, a Mexican fly whose eggs, 

 deposited on rushes, &c. in large quanti- 

 ties, are collected and used as a sort of 

 caviare, called ahuauhtli. 



AXE'STONE, a mineral ; a sub-species of 

 jade, which in some respects resembles 

 nephrite. It occurs in New Zealand and 

 the isles of the Pacific, where it is made 

 into axes and other cutt ng instruments 

 by the natives, from which circumstance 

 it has obtained its name. 



AXIF'EROUS, Lat. axis, a centre, and 

 fero, I bear. Raid of those plants which 

 consist solely of an axis with foliage or 

 other appendage. 



AX'IL, Lat. arilla. 1. In anatomy, the 



arm-pit. 2. In botany, the angle formed 



by the stalk of a leaf with the stem. 



AX'ILE, Lat. axis, lying in the axis of 

 anything, as an embryo in the axis of a 

 s.-;td ; viz., from the base to the end dia- 

 metrically opposite. 



AX'ILLARY, Lat. axiOfiris, pertaining to 

 axilla, the arm-pit. IE it tani , applied to 

 lea-res, Ac. which rro"l from tho as#l; 



formed by the atom and branch. Gent- 

 rally, applied to parts which spring from 

 the point of union of two or more other 

 parts. 



AX'INITB, thnnderstone, (thumer stein, 

 "Werner). A mineral commonly found in 

 crystals of four-sided prisms, so flattened 

 that some o/ its edges become thin and 

 sharp ; hence its name from et^ivn an ax, 

 and \idot stone. Colours, brown, grey, 

 black and violet. 



Ax'is.oguy. This term is applied in 

 the language of science to a right line 

 passing through the centre of a body oa 

 which it may revolve. The axis may 

 either be real or imaginary, as : 1. In 

 mathematics, th<> straight line which 

 divides the area of a figure and about 

 which it revolves to produce a solid. 

 Further, the straight line dra^r. from a 

 point in the periphery through the cen- 

 tre of a sphere is its axis ; and a straight 

 line drawn from the vertex of a cone 

 through the centre of its base io the axis 

 of the cone. See CONE and CONIC SECTIONS. 

 2. In mechanics, the line about which 

 a balance moves or rather turns is the 

 axis of the balance ; the ari* of oscillation 

 is a right line parallel to the horizon, 

 about which a pendulum vibrates ; the 

 axis in peritrochio is another name for 

 the mechanical contrivance called the 



wheel and axle. 3. In optics, that ray of 



light which passing from the eye falls 

 perpendicularly on the eye. 4. In as- 

 tronomy, an imaginary right line passing 

 through the two poles and the centre of 

 the sphere, is called the axis of the sphere, 

 and similarly the sun and all the planets 

 are each conceived to revolve about their 



respective axes. 5. In botany, a taper 



column in the centre of some flowers 

 about which the other parts are disposed. 



6. In anatomy, the second vertebra of 



the neck : the atlas rotates on its tooth- 

 like process as on an axis. 



AXOT'OIIOUS, from iai an art*, and 

 '/*, to cut. A mineralogical term, sig- 

 nifying cleavable in one particular direc- 

 tion. 



AIE-ATE, the name given by the 

 natives to an animal of Madagascar, 

 Cheiromys Madagascariensis. for its pe- 

 culiar cry. It is a nocturnal quadruped, 

 size of a hare, burrows, and motion seems 

 painful to it. 



AZA'LEA, an extensive genus of plants of 

 the class pentandria,a.na oric.rmonogynia. 

 Name from a<zAo? , arid, because found 

 only in such places. The trailing azalea, 

 a low shrub with very woody tortuous 

 stems, and crowded leafy branches, found 

 plentifully on the Scottish Highland 

 mountains, is the only British type. 



Az'iMUTE,froc2 Ar.al and tatr.ath.ps.ih. 

 In astronomy, the arc of the horizon inter- 



