ALL 



A L U 



which yields a fine red, and is much used 

 by dyers. 



A'LLAGITB. A mineral ; colour brown or 

 green ; massive ; semi-opaque ; fracture 

 conchoidal : it is a carbo -silicate of man- 

 ganese. 



A'LLANITE. An orthitic melane-ore. The 

 cerium oxyde siliceux of Haiiy. A mi- 

 neral brought from Greenland, and thus 

 named after Mr. Thomas Allan, of Edin- 

 burgh, who first distinguished it as a pe- 

 culiar species. According to the analysis 

 of Dr. Thomson, allanite was found to 

 contain silica 35.4, oxide of cerium 

 33-9, oxide of iron 25-4, lime 9'2, 

 alumina 4-1, moisture 4'0. 



It is of a black colour, inclining to grey 

 or brown. It is found massive, or in acicu- 

 lar crystals. External lustre imperfect, 

 metallic ; internal, shining. Fracture 

 conchoidal. Opaque. Streak greenish 

 or brownish-grey. It is a siliceous oxide 

 of cerium. 



A'LLOCHROITE. A mineral variety of the 

 dodecahedral garnet. It is found mas- 

 sive, of a green, brown, grey, or yellowish 

 colour ; lustre glimmering. It consists 

 of silica, lime, carbonate of lime, oxide of 

 manganese, oxide of iron, alumina, and 

 moisture. Before the blow-pipe it melts 

 into an opaque black enamel. 



A'LLOPHANE. A mineral of a blue, green, 

 or brown colour, occurring massive, or in 

 imitative shapes. It is rather hard and 

 brittle. It gelatinizes in acids. Accord- 

 ing to the analysis of Stromeyer, it con- 

 sists of alumina, silica, carbonate of cop- 

 per, lime, iron, sulphuric acid, and 

 water. 



ALLO'Y. To alloy, called also allay, is to 

 mix one metal with another, in order to 

 give greater hardness, fusibility, &c. To 

 diminish the pureness of a metal by mix- 

 ing with it one of less value. 



ALLO'Y. 



1. A mixture of different metals : it must, 

 however, be kept in mind that when 

 mercury forms one of the metals, the 

 mixture is called amalgam. 



2. The metal of inferior value, which is 

 used to deteriorate, or give new proper- 

 ties to, another metal. 



ALLU'VIAL. That is carried by water to 

 another place, and lodged upon something 

 else. 



ALLU'VION. ) (alluvio, Lat. alluvion, Fr. 



ALLU'VIUM. $ alluvione, It.) Earth, sand, 

 gravel, stones, or other transported mat- 

 ter which has been washed away and de- 

 posited by water upon land not perma- 

 nently submerged beneath the waters of 

 lakes or seas. Lyell. 



Alluvium has been divided into mo- 

 dern and ancient. The modern, cha- 

 racterized by the remains of man and 



contemporaneous animals and plants ; 

 the ancient, by an immense propor- 

 tion of large mammalia and carnivora, 

 both of extinct and recent genera and 

 species. 



ALLU'VIOUS. See Alluvial. 



A'LMANDINE. (almandine, Fr. alabandina, 

 It.) A precious stone, having some of 

 the characters of the garnet ; a species of 

 ruby. 



A'LPINE. (alpinus, Lat.) This term is 

 not confined merely to the Alps, and the 

 things therewith connected, but is ap- 

 plied to any lofty or mountainous country, 

 and to the productions of elevated situ- 

 ations. 



ALTE'RNATE. (alternus, Lat.) Being by 

 turns ; one after another ; reciprocal. In 

 botany, applied to leaves when they stand 

 singly on the stem or branches, alternately 

 first on one side, then on the other ; to 

 branches when placed round the stem al- 

 ternately, one above the other ; to flowers 

 placed in regular succession, one above 

 another. 



ALTE'RNATE, n. s. That which happens 

 alternately ; vicissitude. 



ALTERNATELY. In reciprocal succession, 

 so that each shall be succeeded by that 

 which it succeeds. 



ALTE'RNATENESS. The quality of being 

 alternate, or of happening in reciprocal 

 succession. 



ALTERNATION. Reciprocal succession. 



ALTERNATIVELY, (alternativement, Fr. 

 alternativemente, It.) Reciprocally ; in 

 alternate manner. 



ALTE'RNITY. Reciprocal succession ; vi- 

 cissitude ; turn. 



ALTERNATING. Following, or succeeding, 

 reciprocally ; happenin^in reciprocal suc- 



ALTI'METER. ^(from altus, Lat. 



Gr.) An instrument by which the heights 

 of bodies may be ascertained. 



ALTI'METRY. (altimetrie, Fr. altimetria, 

 It.) The art of measuring altitudes or 

 heights, whether accessible or other- 

 wise. 



A'LTITUDE. (altitudo, Lat.) Height of 

 place ; space measured upwards. 



A'LTIVOLANT. (altiv&lans, Lat.) High- 

 flying. 



A'LUM. (alumen, Lat. alun, Fr. allume, It.) 

 A triple sulphate of alumina and potassa. 

 Alum is both native and factitious. The 

 common mode of obtaining alum is by 

 roasting and lixiviating certain clays con- 

 taining pyrites ; to the leys a certain 

 quantity of potassa is added, and the tri- 

 ple salt is obtained by crystallization. 

 Alum has a sweetish astringent taste. It 

 dissolves in five parts of water at a tem- 

 perature of 60, and the solution reddens 

 blues. 



