ALU ! 



ALU'MINA, ) one of the primitive 

 ALU'MINE, / earths, which, as consti- 

 tuting the plastic principle of all clays, 

 loams and boles, was called argil, or the 

 argillaceous earth, but now being ob- 

 tained in greatest purity from alum, it 

 is called alumina. Iii its mixed state it is 

 one of the most abundant substances in 

 nature, but pure and unmixed it is one of 

 the rarest. The sapphire and ruby are 

 perhaps the purest native specimens of it : 

 these gems are simply the clay crystal- 

 lized and combined with small portions 

 of colouring matter. To obtain it pure, 

 it must be precipitated from alum by 

 means of ammonia. Thusobtained.it is 

 destitute of smell or taste, insoluble in 

 >rater, but mixes with it readily: may be 

 made into a ductile paste, and kneaded 

 into regular forms. Alumina was deemed 

 an elementary substance, till Sir H. 

 Davy's electro-chemical researches led to 

 the knowledge that it is a metallic oxide, 

 the metallic basis of which is called alu- 

 minum, (q. v.). It consists of 52'94 alu- 

 minum, and 47"06 oxygen. 



ALU'MINITE, a mineral of a snow-white 

 colour, dull, opaque, and having a fine 

 earthy fracture. It is a native subsulphate 

 of alumina, and occurs chiefly in the al- 

 luvial strata round Halle, in Saxony. 



ALU'MINUM, the metallic basis of alu- 

 mina. It somewhat li resembles pla- 

 tinum in powder." Sp. gr. 13'7. The 

 experiments of Sir H. Davy first led to 

 the belief that alumina is a metallic 

 oxide, but it was "Woehler who first suc- 

 ceeded in separating the metallic sub- 

 stance. 



ALUM-SLATE, \ a bluish or greenish 

 ALUM-SCHKT, ) black mineral, contain- 

 ing more or less, iron pyrites mixed with 

 coaly or bituminous matter. It occurs in 

 the strata of brown coal, where the upper 

 layers lie immediately under clay-beds. 

 Prom this schist the greater portion of the 

 alum manufactured in Britain is made. 

 Minerologists distinguish between com- 

 mon and glossy alum-slate. 

 ALCM-STONE, j Alum-stone is a mineral 

 ALCM-ROCK. j of a white colour, 

 sometimes inclined to grey. It occurs in 

 beds of a hard substance, characterised 

 by numerous cavities, containing drusy 

 crystallizations of basic alum. The beds 

 in which the alum-stone occurs, is called 

 alum-rock. Hungary yields large quan- 

 tities. The alum-stone contains all the 

 constituents of alum, being a siliceous 

 Bubsulphate of alumina and potash: the 

 alum-schists contain only two of them. 

 Clay and sulphur, convertible into sul- 

 phate of alumina: the alkali must be 

 added. 



ALCTA (Lat. for tanned leat\er). Leather- 

 stone ; a soft, pliable mineral, not lami- 

 nated. 



r A M A 



ALVE'ART, Lat. aleeariwn, of alveare, a 

 bee-hive. The meatus auditoriut externus, 

 the hollow of the external ear, or bottom 

 of the concha, where the wax is con- 

 tained. 



ALVE'oLAR.Lat. alveolarit. Appertaining 

 to the alveoli or sockets of the teeth. 



ALVB'OLATE, Lat. alveolatus. Having 

 small cavities, so as to resemble a honey- 

 comb. 



ALVE'OLE, Lat. ali-folus. A little cavity. 

 Technically : 1. A cell in a honey-comb, 



in a fossil, &c. 2. A socket in which 



a tooth is placed. 3. A marine fossil, 



of a conical figure, composed of a number 

 of cells like a honey-comb, joined by a 

 tube of communication. 



ALVE'OLITE, a marine fossil composed of 

 numerous concentric beds, each formed by 

 the union of hemispherical cells : the body 

 itself is usually of a hemispherical shape. 

 From alveolus, and X/0o?- Only one spe- 

 cies is known, and it occurs in the Port- 

 land stone. 



AL'VIXE, Lat. alvinus. Appertaining to 

 the belly (alvus) : usually applied in rela- 

 tion to the intestinal excretions. 



AL'VUS (Lat.), the belly: used in ana- 

 tomy. 



ALT'PON, the Globularia alypum of Lin. 

 It is a drastic purgative. Name, from at, 

 not, and XM7>), pain. 



ALY'SM, Lat. alysmus, of aXw*i, to be 

 anxious. The inquietude which a patient 

 exhibits under disease. 



ALYS'SUM, the generic name of the plant 

 madicort, supposed to be a specific in cases 

 of hydrophobia. Class tetradidynamia, 

 order siliculosa. There are ten species, all 

 foreign. Name, from , not, and Atia^a, 

 hydrophobia. 



A.M. stand for artium magister, master 

 of arts, the second degree given by uni- 

 versities and colleges, and called in some 

 countries doctor of philosophy. Also for 

 anno mundi, in the year of the world ; and 

 ante meridiem, before noon. 



A'MA, from Dan. aam, a vessel. Written 

 also Haina. 1. In church affairs, a vessel 



to contain the wine for the Eucharist. 



2. A wine measure of indefinite size, as a 

 cask, a pipe. 



AMABY'R, an old British word, signify- 

 ing " the price of virginity ," and express- 

 ing a barbarous custom which formerly 

 prevailed in England and Wales, being a 

 sum of money paid to the lord when a 

 maid was married within his lordship. 



AMACRA'TIC, 1 A lens photographically 



AMASTHE'NIC. /perfect, or which unite* 

 all the chemical rays into one focus, may 

 be called amacratic (etfMt., together, and 

 *{<To;, power), or amasthenic (f6trf, 

 force). If this nomenclature be adopted, 

 a diacratic or diasthcnic medium will be 

 one which transmits the chemical powet 



