ALL 



ALM 



ALLA'NTOIC ACID {allantois, a 

 membrane situated between the amnion 

 and the chorion). A white crystallizable 

 acid, described by Vauquelin under the 

 name of amniotic acid, and said to exist 

 in the liquor amnii of tbe cow. Tliis 

 fluid contains a crystalline substance 

 called allantoin. 



A'LLEGORY (aWrjTopt'a, a descrip- 

 tion of one thing under the image of an- 

 other). In Rhetoric, a figurative repre- 

 sentation by which some meaning is 

 signified beyond what is expressed: as 

 in the " Fairy Queen" of Spenser, and 

 Swift's '« Tale of a Tub." 



ALLE'GRO. An Italian adjective, 

 signifying gatj, sportive, and denoting, 

 in music, quick time. Allegretto is a 

 diminutive of allegro, and denotes a tune 

 rather quick and sportive, but less so 

 than that indicated by the term allegro. 



ALLIA'CEOUS {allimn, garlic). A 

 terra applied to any thing which has the 

 odour of garlic. In botany, i\ denotes 

 plants which partake of the properties of 

 garlic or of the onion. 



ALLIGA'TION (alligo, to bind toge- 

 ther or unite). A rule in arithmetic, 

 applied only in commerce, by which the 

 price of a mixture is found, when the 

 price of the ingredients is known. Me- 

 dial alligation is the method of finding 

 the rate or quality of a compound, from 

 the given rates and quantities of the in- 

 gredients. Alternate alligation is the 

 method of finding the quantities of ingre- 

 dients necessary to form a compound of 

 a given rate. 



A'LLIOTH. A star of the third mag- 

 nitude in the tail of the Great Bear. 



ALLITERATION {ad, to, litera, a 

 letter). In composition, the frequent 

 recurrence of the same letter at the com- 

 mencement of words, as in the line of 

 Churchill, 



*'And apt alliteration's artful aid." 



A'LLOCHRO'ITE (SXXor, another, 

 xpoa, colour). A mineral allied to the 

 garnet, exhibiting several changes of 

 colour, when melted with phosphate of 

 soda before the blowpipe. 



A'LLOPHANE (ciXAoc, diflferent, 0a/- 

 vofxat, to appear). A mineral of a blue, 

 green, or brown colour, formerly called 

 Riemannite, and found in a bed of iron- 

 shot lime-stone in Greywacke slate, in 

 the forest of Thuringia. 



A'LLOTROPIC STATE (JiXXo?, an- 

 other, TpoTTof, condition). A term applied 

 to the dissimilar condition observed in 

 certain elements of which the various 

 18 



forms of carbon, as diamond, grapln'te, 

 &c., afford a well-known example. This 

 is one of the causes of the isomerism of 

 their compounds. 



ALLO'XAN; ALLOXA'x\TIN. Com- 

 pounds containing cyanogen and carbonic 

 oxide, and discovered in the decomposi- 

 tion of uric acid. Alloxan is another 

 name for the erythric acid of Brugna- 

 telli. Alloxanic acid is produced by the 

 metamorphosis of alloxan by caustic 

 alkalies. 



ALLO'Y {alloyer, French, to mix one 

 metal with another, for the purpose of 

 coinage). A natural or artificial com- 

 pound of two or more metals, as brass, 

 bell-metal, bronze, &c. But the term is 

 not employed when mercury enters into 

 the compound ; it is then called an amal- 

 gam. 



ALLU'VIUM {alluo, to wash upon). 

 A general designation of earth, sand, 

 gravel, stones, and other transported 

 matter, which have been washed away 

 and thrown down by rivers, floods, or 

 other causes, upon land not permanently 

 submerged beneath the waters of lakes 

 and seas. 



Alluvial Deposits. These are divided 

 by many authors into two kinds. 1. Old 

 Alluvium, or Diluvium, which is gene- 

 rally referred to the tertiary series, and 

 often contains remains of animals, more 

 or less resembling those living at the 

 present day. 2. Recent Alluvium, or 

 deposits of the same nature, but pro- 

 duced by causes wliich are in operation 

 at the present day. 



ALMAAC. A star of the second mag- 

 nitude in the northern constellation An- 

 dromeda 



ALMACA'NTER. An Arabic term 

 formerly employed in astronomy to de- 

 note a small circle of the sphere parallel 

 to the horizon. Two stars which have 

 the same almacanter, have the same alti- 

 tude, and hence the term almacanter sig- 

 nifies a circle of altitude, just as a small 

 circle parallel to the equator, all whose 

 points have therefore the same declina- 

 tion, is called a circle of declination. 



A'LMANAC. An Arabic term signi- 

 fying reckoning, and applied to a calen- 

 dar, wherein the days of the month, fes- 

 tivals, lunation, motion of the heavenly 

 bodies, eclipses, &c., are reckoned for 

 each year. See Era. 



A'LMANDINE. A designation of pre- 

 cious or noble garnet, occurring in pri- 

 mitive rocks and primitive metalliferous 

 j beds, and used for ring-stones. 



