90 ALLOY 



It is the same as the herb Henna frequently referred to by the Oriental poets. 

 The powder of the loaves, being wet, forms a paste, which is bound on the nails for a 

 night, and the colour thus given -will last for several -weeks. 



This plant is distinguished as the true alkanot root (radix alkannts vera). 

 ALIiEIVIONriTE. A native alloy of a'rsenic and antimony, containing Sb As 3 . 

 It is found at Allomont, in Daupliiny (whendo the name) ; at Przibram, in Bohemia ; 

 and at Andreasberg, in the Hartz. 



AZiXiICr ATXOttr. An arithmetical formula, useful on many occasions for ascertain- 

 ing the proportion of constituents in a mixture, when they have undergone no change 

 of volume by chemical action, or for finding the price or value of compounds consist- 

 ing of ingredients of different values. Thus, if a quantity of sugar worth 8d. the 

 pound, and another quantity worth Wd., are mixed, the question to be solved by 

 alligation is, what is the value of the mixture by the pound ? Alligation is of two 

 kinds medial, and alternate ; medial, when the rate of mixture is sought from the 

 rates and quantities of the simples ; alternate, when the quantities of the simples are 

 sought from the rates of the simplos and the rate of the mixture. Webster. 



AIiIiXOIiX:. Attiolc is obtained by distilling crude naphtha, and collecting all that 

 leaves the still in the first distillation before the boiling temperature reaches 194 F. ; 

 and on the second distillation, all below 176 F. It boils, when nearly free from 

 benzole, at a temperature of from 140 to 158 F., and possesses an alliaceous odour 

 somewhat resembling that of bi-sulphide of carbon. 



AXiXiTDlVI. A genus of plants belonging to the Liliacces or lily-order. The bulbs 

 of many species are esculent. Attium Cepa is the onion ; A. sativum, garlic ; A. porni m, 

 the leek; A. Ascalonicum, the shallot; A. Schcenoprasum, the chive. The so-called 

 ' Spanish onions,' imported from Spain, Portugal, and Egypt, are merely the largo 

 bulbs of varieties of the common onion, which, cultivated in warm dry countries, lose 

 much of their pungency. 



ALIiOCIiASH. A mineral found in the Bannat once regarded as a Cobalt- 

 glance. It appears to bo of a very complex and variable composition. -Essentially 

 it is a compound of sulphur, arsenic, iron, zinc, and cobalt. 



AEiliOPHATtfE from &\\os other, and <palvta to appear, in allusion to the change 

 of appearance which this mineral undergoes before the blowpipe flame. This mineral, 

 which is a hydrated silicate of alumina, consists essentially of silica 24'22, alumina 

 40-39, and water 35'39. It is generally found lining small cavities, and in veins in 

 marl or chalk. Allophanes have been found containing from 14 to 19 per cent, of 

 oxide of copper, which give them a green colour. 



AXiXiOTROPY. Allotropic Condition. A name introduced by Berzelius to signify 

 anotJter form of the same substance, derived from &\\os, another, and rp6iros, habit. 

 Carbon, for example, exists as the diamond, a brilliant gem, with difficulty combus- 

 tible ; as graphite, a dark, opaque mass, often crystalline, also of great infusibility ; 

 and as charcoal, a dark porous body, which burns with facility. 



Sulphur, when melted, is at 230 F. perfectly liquid. Being heated to 430 F., it 

 becomes thick and so tenacious that it can scarcely bo poured out of the vessel in 

 which it is melted. When heated to 480 it again becomes liquid, and continues so 

 until it boils. These examples are sufficient to explain the meaning of this term. 

 An extensive series of bodies appears to assume similar allotropic modifications. 

 The probability is that, with the advance of physical and chemical science, many of 

 the substances now supposed to be elementary will be proved to be but allotropic 

 states of some one form of matter. See ISOMERISM. 



AXiXiOY. (Alliage, Fr. ; Legirung, Ger.) From the French oilier, to unite or mix ; 

 or the Latin alligo, to bind. This term formerly signified mixing some baser metal 

 with gold and silver, and this meaning is still preserved in reference to coinage ; but, 

 in chemistry, it now means any compound of any two or more metals whatever. Thus, 

 bronze is an alloy of copper and tin ; brass, an alloy of copper and zinc ; and typo 

 metal, an alloy of lead and antimony. All the alloys possess metallic lustre, even 

 when cut or broken to pieces ; they are opaque ; are excellent conductors of heat and 

 electricity; are frequently susceptible of crystallising; are more or less ductile, 

 malleable, elastic, and sonorous. An alloy which consists of metals differently fusible 

 is usually malleable when cold, and brittle when hot, as is exemplified with brass and 

 gong metal. 



Many alloys consist of definite or atomic proportions of the simple component 

 metals, though some alloys seem to form in any proportion, like combinations of salt 

 or sugar with water. It is probable that peculiar properties belong to the atomic 

 ratio, as is exemplified in the superior quality of brass made in that proportion. 



The experiments of Crookewitt upon amalgams appear to prove that the combina- 

 tion of metals in alloys obeys some laws of a similar character to those which prevail 

 between combining bodies in solution ; i.e. that a true combining proportion existed. 



