134 AMBAB, LIQUID 



and solidity ore considerable. "VYhon hoatod nearly to tho point of boiling -water this 

 amalgam swells up, drops of mercury exuding, which disappear again on tho cooling 

 of the substance. If a piece, thus heated, bo rubbed up in a mortar, a plastic 

 mouldable mass, like poor clay, is obtained, tho consistence of which may, by con- 

 tinued kneading, bo increased to that of fat clay. If the moulded mass be left for ton 

 or twelve hours, it hardens, acquiring again its former properties, without altering its 

 specific gravity. Hence the stopping, after it has hardened, remains tightly fixed in 

 the hollow of the tooth. The softening and hardening may be repeated many times 

 with the same sample. Pettenkofer ascribes these phenomena to a state of 

 amorphism, into which the amalgam passes from the crystalline condition in the 

 process of softening. All copper amalgams containing between 0'25 to 0-30 of copper 

 exhibit the same behaviour. Tho above chemist recommends, as the best mode of 

 preparing this amalgam, that a crystalline paste of sulphate of suboxide of mercury 

 (prepared by dissolving mercury in hydrated sulphuric acid at a gentle heat) bo 

 saturated under water at a temperature of from 60 to 70, with finely divided 

 reguline copper (prepared by precipitation from sulphate of copper with iron). One 

 portion of the copper precipitates the mercury, with formation of sulphate of copper ; 

 the other portion yields with mercury an amalgam : 100 parts of dissolved mercury 

 require the copper precipitated, by iron, from 232-5 parts of sulphate of copper. As 

 in dissolving the mercury the protoxide is easily formed instead of the suboxido, par- 

 ticularly if too high a temperature be maintained, it is advisable, in order to avoid an 

 excess of mercury in the amalgam, to take 223 parts of sulphate of copper, and to add 

 to tho washed amalgam, which is kept stirred, a quantity of mercury in minute 

 portions, corresponding to the amount of suboxide contained in the mercury salt, until 

 the whole has become sufficiently plastic. This amalgam may be obtained by 

 moistening finely-divided copper with a few drops of a solution of nitrate of suboxide 

 of, mercury, and then triturating the metal with mercury in a warmed mortar. The 

 rubbing may be continued for some time, and may be carried on under hot water, 

 mercury being added until the required consistence is attained. 



A remarkable depression of temperature during the combination of amalgams has 

 been observed by several chemists. 



Dobereiner states that when 816 grains of amalgam of lead (404 mercury and 412 

 lead) were mixed, at a temperature of 68, with 688 grains of the amalgam of 

 bismuth (404 mercury and 284 bismuth) the temperature suddenly fell to 30, and by 

 the addition of 808 grains of mercury (also at 68), it became as low as 17 ; the total 

 depression amounting to 51. 



In certain proportions of mixture of the constituents of fusible metal (tin, lead, and 

 bismuth) with mercury, Db'beroiner formed surprising depressions of temperature ; the 

 temperature, he records of one experiment, sank instantly from 65 to 14. 



AlVIAXiGAIVIATIONr. See GOLD and SILVER. 



AMAXiXC ACID. A feeble acid obtained by decomposing caffeine with 

 chlorine. 



AMANDINE. An albuminous compound, said to exist in sweet almonds. 



AIVXANIT.A. XVXTTSCARIA. A poisonous fungus used in Kamtschatka and 

 Siberia as a narcotic and intoxicating 'agent. The specific name has reference to its 

 use, when steeped in milk, as a fly-poison. An organic base, called amanitine, has 

 been separated from this fungus. By some authorities tho poisonous properties are 

 referred to the presence of a peculiar acid called muscaric acid. 



A1VXARXNE, or Benzoline. C^H^N 2 (C 21 H 18 N 2 ). An organic base obtained 

 by boiling hydrobenzamide with solution of caustic potash. Tho hydrobenzamide is 

 prepared by the action of ammonia on pure oil of bitter almonds. 



A1VIAZON STONE. A bluish-green variety of Felspar (Orthoclase). It is found 

 at Lake Ilmen in Kussia, of a verdigris-green variety. That from Baikal in Siberia 

 is composed of silvery spangles in a green base, of which small vases and other orna- 

 ments are made. See FELSPAR. 



AIV1B AR, LIQUID. (Ambre Liquide, Fr.) In former editions of this Dictionary, 

 the liquid-ambar, as it was called, was confounded with liquid storax or styrax. It 

 is obtained from the Liquidambar styraciflua of Linnaeus, growing in Louisiana and 

 Mexico, whereas the storax is procured chiefly it is now entirely from Trieste; 

 storax was originally extracted from the Styrax officinalis, which grows in various 

 parts of Greece, but this resin is lost to commerce, and the present commercial liquid 

 storax appears to be obtained from Liquidambar orientale (Miiller). Pereira, quoting 

 Buchner's ' Repertorium,' informs us that the storax is known in tho East as buchuri- 

 jag. Liquid-ambar is rarely used in any art or manufacture. It is brownish ash- 

 grey, of the consistence of turpentine, dries up readily, smells agreeably, like benzoin, 

 has a bitterish, sharp, burning taste ; is soluble in 4 parts of alcohol, and contains 

 only 1'4 per cent, of benzole acid. 



