ALL 



[ 



A'LGOUS. (algosus, Lat.) Having the 

 nature, or characters, of sea- weed. 



A'LKALI. (from the Arabic word kali, 

 with the usual prefix al ; the name 

 given by the Egyptians to the plant 

 called by us glasswort.) Any sub- 

 stance which, by uniting with an 

 acid, neutralizes or impairs its 

 activity, and forms a salt. Alkalies 

 possess the property of converting 

 vegetable blues to green, and yel- 

 lows to red. There are three kinds 

 of alkalies: 1. The vegetable alkali, 

 or potash ; 2. The mineral alkali, 

 or soda ; 3. The animal, or volatile 

 alkali. 



ALKALI'NITY. The property of chang- 

 ing vegetable blues into green. 



ALKALI'METEK. An instrument for 

 ascertaining the proportion of alkali 

 contained in any substance. 



A'LKALOID. A body possessing some 

 of the properties of an alkali. 



A'LKANET. The name of a plant the 

 root of which yields a fine red, and 

 is much used, by dyers. 



A'LLAGITE. A mineral ; colour brown 

 or green ; massive; semi-opaque; 

 fracture conchoidal : it is a carbo- 

 silicate of manganese. 



A'LLANITE. An orthitic melane-ore. 

 The cerium oxyde siliceux of Haiiy. 

 A mineral brought from Greenland, 

 and thus named after Mr. Thomas 

 Allan, of Edinburgh, who first dis- 

 tinguished it as a peculiar species. 

 According to the analysis of Dr. 

 Thomson, allanite was found to 

 contain silica 3 5 -4, oxide of cerium 

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

 alumina 4*1, moisture 4. 



It is of a black colour, inclining 

 to grey or brown. It is found 

 massive, or in acicular crystals. 

 External lustre imperfect, metallic; 

 internal, shining. Fracture con- 

 choidal. Opaque. Streak greenish 

 or brownish-grey. It is a siliceous 

 oxide of cerium. 



ALLIACEOUS, (from allium, garlick, 

 Lat.) Resembling garlick ; a term 

 usually applied to substances which, 



; ] ALL 



on being heated, emit the odour of 

 garlick. 



A'LLOCHROITE. A mineral variety of 

 the dodecahedral garnet. It is found 

 massive, of a green, brown, grey, 

 or yellowish colour ; lustre glim- 

 mering. It consists of silica, lime, 

 carbonate of lime, oxide of manga- 

 nese, oxide of iron, alumina, and 

 moisture. Before the blow-pipe it 

 melts into an opaque black enamel. 

 It was first discovered and described 

 by Dandrada, and hitherto it has 

 only been met with in an iron 

 mine, near Drammen, in Norway. 

 Sp. gravity 3'58. 



A'LLOPHANE. A mineral of a blue, 

 green, or brown colour, occurring 

 massive, or in imitative shapes. It 

 is rather hard and brittle. It gela- 

 tinizes in acids. According to the 

 analysis of Stromeyer, it consists of 

 alumina, silica, carbonate of copper, 

 lime, sulphuric acid, and water. 



ALL'OTEOPISM. (from aXXorpoTros, Gr. 

 that can be turned from one thing 

 into another.) A term in mineral- 

 ogy, as opposed to isomorphism. 

 A modification in the properties of 

 a body, not resulting from chemical 

 combination. 



ALLO'T. 



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 properties to, another 

 metal. 



ALLU'VIAL. That is carried by water 

 to another place, and lodged upon 

 something else. 



ALLUVIAL DEPOSITS. These consist 

 in the accumulation of sand, shingle, 

 and debris, along the sea-coast ; in 

 the formation of new lands on the 

 banks of rivers and lakes by the 

 alluvial depositions they carry down; 

 in the growth and increase of tracts 

 of marsh land; and in the accretion 



