A L U 



C 10 ] 



A M B 



A'LUM-STONE. The shale from which alum 



is extracted. 

 ALU'MINA. ) Pure argillaceous earth, or alu- 

 A'LUMINE. ) mina, is a substance which 

 in a mixed state is well known, but pure 

 and unmixed, is one of the rarest sub- 

 stances in the mineral kingdom. This 

 earth is soft, smooth, and unctuous to the 

 touch. Combined with other earths, or 

 rocks, it communicates to them some ol 

 these properties ; such rocks are termed 

 argillaceous. Alumina constitutes some 

 of the hardest gems, such as the ruby and 

 sapphire, the latter being crystallised alu- 

 mine. According to the analysis of Kla- 

 proth the sapphire contains 95 per cent. 

 of pure clay. Alumina was considered an 

 elementary substance till Sir Humphry 

 Davy's electro- chemical researches led to 

 the opinion of its being a metallic oxide. 

 Next to silicium, aluminum would ap 

 pear to be the most important base of the 

 earths on the face of the globe. Its col- 

 lective amount is by no means so great as 

 that of silicium, but it is quite as widely 

 spread. There is scarcely one among the 

 mechanical rocks that does not contain 

 alumina. It constitutes the base of the 

 various clays, and must be regarded as a 

 very abundant and important constituent 

 part of rocks. It contains 46 - 8 per cent, 

 of oxygen. De la Beche. 

 ALU'MINITE. Sub-sulphate of alumine. A 

 white mineral, dull, opaque, and having 

 an earthy fracture. This mineral occurs 

 massive, in veins, and in tabular and tu- 

 berose masses ; the former frequently at- 

 taining a length of several feet, and the 

 latter a weight equal to three or four 

 pounds. It appears to have been of sta- 

 lactitical origin, and is supposed to result 

 from the decomposition of iron pyrites, 

 and the reaction of other substances. It 

 is infusible at 166 of Wedgewood, but 

 fuses rapidly when exposed to the stream 

 of the hydro- oxygen blow-pipe. Accord- 

 ing to the analysis of Stromeyer, it con- 

 sists of alumine 30, sulphuric acid 25, 

 water 45. 



ALU'MINOUS. Having the properties of 

 alum; containing alum; resembling 

 alum. 



ALU'MINUM. The metallic base of alumina. 

 The metal itself has not yet been obtained 

 in a separate state, but the analyses to 

 which alumina has been subjected have 

 clearly shewn that it is a metallic 

 oxide. 

 ALVE'OLAR. (alveolus, Lat.) Containing 



sockets, pits, hollows or cavities. 

 ALVE'OLATE. Pitted or honey-combed. 

 ALVEOH'NA. A genus of microscopic fora- 



miniferous shells. 



ALVE'OLUS. (alveolus, Lat. alvtole, Fr. al- 

 veolo, It.) A socket for a tooth ; a small 



cavity or cell ; the cell of the honey- 

 comb. 



ALVE'OLUS. > A fossil marine body, large at 



ALVE'OLITE. $ one end and tapering to- 

 wards the other, composed of hemispheric 

 cells. 



AMA'LGAM. (from lipa, together, and ya- 

 /IEW, to marry.) A compound of any 

 metal with mercury. When two or more 

 metals, neither being mercury, are mixed 

 together, the compound is termed an al- 

 loy, but when mercury enters into the 

 composition it is called an amalgam, and 

 its derivation has been supposed to be 

 from /Lia\ay/wa, or /iceXdaaw, to soften, 

 which derivation appears to be more cor- 

 rect than that of Johnson, and lexicogra- 

 phers generally. 



AMALGAMATE, (amalaamer, Fr. amalga- 

 mare, It.) 



1. To mix mercury with any other metal. 



2. To mix any two substances capable of 

 uniting into one body. 



AMALGAMATION. (amalgamation, Fr. 

 amalgamazione, It.) 



1. The act of mixing mercury with other 

 metals. 



2. The act of blending different bodies. 

 AMA'LTHUS. A species of ammonite. 

 A'MAZON- STONE. A variety of prismatic 



felspar, of a blue or green colour. 

 A'MBER. (ambar, Arab.) A fossil resin. 

 For a great length of time, various were 

 the opinions as to the nature and compo- 

 sition of amber, but it is now well ascer- 

 tained to be a fossilized vegetable resin. 

 It is found in similar localities to coal and 

 jet. It is brittle, easily cut with a knife, 

 of various shades of yellow, sometimes 

 nearly white, and semi-transparent : in- 

 sects are frequently found enclosed in it, and 

 Jussieu states that these are not European. 

 Its constituent parts are carbon 70*68, 

 hydrogen 11 '62, oxygen 777. Amber is 

 found in nodular masses, which are some- 

 times eighteen inches in circumference; 

 that which is found on the eastern shores 

 of England, and on the coasts of Prussia, 

 and Sicily, is derived from beds of lignite in 

 tertiary strata. Fragments of fossil gum 

 were found near London in digging the 

 tunnel through the London clay at High- 

 gate. In the royal cabinet of Berlin there 

 is a lump of amber, discovered in Lithua- 

 nia, weighing eighteen pounds. Amber 

 is one of the most electric substances 

 known ; when submitted to distillation, it 

 yields an acid sublimate, which has re- 

 ceived the name of succinic acid. Ten 

 pounds of amber yield about three ounces 

 of purified succinic acid. 

 AMBE'RGRIS. ^from amber and ffris, or 

 grey.) A concretion from the intestines 

 of the physeter macrocephalus, or sper- 

 maceti whale. It was long doubted of 



