AMI 



AMN 



Formed for walking ; as applied to the 

 feet of those birds in which the toes are 

 placed three before and one behind. 

 Such birds were called by lUiger amhu- 

 latores. 



AME'NTUM. A catkin; a form of 

 inflorescence, in which the flowers of a 

 spike are destitute of calyx and corolla, 

 the place of which is occupied by bracts, 

 and the whole inflorescence falls off in a 

 single piece, either after flowering or the 

 ripening of the fruit, as in the hazel and 

 the willow. Plants which have this kind 

 of inflorescence were formerly called 

 ame7daceous. 



AME'RICAN RACE. One of the five 

 principal varieties of mankind, originally 

 spread over the whole of the Americas, 

 south of the sixtieth degree of north lati- 

 tude. This variety is characterized by a 

 reddish-brown complexion, long black 

 lank hair, deficient beard, eyes black 

 and deep-set, receding brow, cheek- 

 bones prominent, but more arched and 

 rounded than in the skull of the 

 Mongolian, aquiline nose, small skull, 

 with the apex high and the back part 

 flat, large mouth, and tumid lips, with 

 fine symmetrical frames of middle 

 height. 



AMETA'BOLA (a, priv., ne-rapoX^rj, 

 change). A term applied by zoological 

 writers to those genera of insects which 

 do not undergo metamorphoses; which 

 escape from the egg nearly under the 

 same form as they preserve through life, 

 and which, on reaching their perfect 

 state, do not acquire wings. See Meta- 

 hola. 



A'METHYST (a, priv., ixed-'ro, to be 

 intoxicated). The oriental amethyst is 

 a rare violet-coloured gem, called corun- 

 dum, or adamantine spar, with the qua- 

 lities of the sapphire or ruby. The occi- 

 dental or common amethyst is merely 

 a coloured crystal or quartz. The name 

 is derived from its reputed virtue of pre- 

 venting intoxication. 



AMIA'NTHOIDE. A flexible, fila- 

 mentous mineral, of an olive green 

 colour, found at Oisans in France. 



AMIA'NTHUS (a, priv., ^mivw, to 

 corrupt). Mountain flax. An incom- 

 bustible mineral, consisting of very deli- 

 cate and regular silky fibres. The term 

 appears to have been derived from the 

 circumstance that soiled cloths, made 

 of this substance, are better cleansed by 

 being thrown into the fire, than by wash- 

 ing. See Asbestos. 



A'MIATITE. Fiorite, or pearl-sinter ; 

 21 



a volcanic production, chiefly silica, in a 

 stalactitical form. 



A'MIDES. A series of saline com- 

 pounds, in which the compound of nitro- 

 gen and hydrogen occurs, containing an 

 atom less of hydrogen than ammonia. 

 The term amidogen has been applied to 

 their radical. 



A'MIDIN {amidon, starch). Gelati- 

 nous starch ; the soluble part of starch ; 

 a substance intermediate between gum 

 and starch. 



A'MILENE. A liquid hydrocarbon, 

 obtained by distilling hydrate of oxide of 

 amyl repeatedly with anhydrous phos- 

 phoric acid. 



A'MMELIDE: A'MMELINE. Two 

 of the products of the decomposition of 

 sulpho-cyanogen. See Melam. 



AMMO'NIA. Ammoniacal Gas. A 

 transparent, pungent gas, formed by the 

 union of nitrogen and hydrogen, and 

 named from the substance sal ammoniac, 

 of which it constitutes the basis. It has 

 also been termed alkaline air, and the 

 volatile alkali. 



AMMONI'ACAL AMALGAM. A sub- 

 stance formed by the action of galvanism 

 on a salt of ammonia, in contact with a 

 globule of mercury. 



AMMONI'ACO. A term prefixed to 

 the names of salts, in which ammonia 

 has been added in sufficient quantity to 

 combine with both the arid and the base. 

 A'MMONITE. An extinct and very 

 numerous genus of molluscous animals, 

 called Cephalopoda, allied to the modern 

 genus Nautilus, which inhabited a cham- 

 bered shell, curved like a coiled snake. 

 Species of it are found in all geological 

 periods of the secondary strata ; but they 

 have not been found in the tertiary beds. 

 From its resemblance to the horns of the 

 statues of Jupiter Ammon, it is called 

 cornu Ammonis; from its coiled form, it 

 is popularly called snake-stone. 



AMMO'NIUM. A hypothetical com- 

 pound of nitrogen and hydrogen. It is 

 not an elementary body, and possibly not 

 even a metal. Berzelius, however, con- 

 sidered it the metallic base of ammonia. 

 AMMONIU'RET. A compound con- 

 taining ammonia and a salifiable base, or 

 other substance not acid. 



A'MNIOS. In Botany, a gelatinous 

 substance, in which the embryo of a seed 

 is at first suspended. It is subsequently 

 absorbed, or solidified in the form of 

 albumen. 



AMNIOTIC ACID. An acid supposed 

 to be found in the liquor amnii of the 



