132 ALVITE 



desired. It docs not clog tho file ; and in the latho and planing-machinc the tool 

 removes long elastic shavings, leaving a fine, bright, smooth surface.' 



Resistance to atmospheric influences. This alloy tarnishes much less readily than 

 any metal usually employed viz. gun-metal, brass, silver, cast-iron, or steel. 



Fitness to receive graduation. The lines are remarkably puro and equable, 

 and very distinct under the microscope, notwithstanding tho yellow colour of the 

 metal. 



Elasticity. No wires tried for tho suspension of Foucault's pendulum for illus- 

 trating the rotation of tho earth wore so durable not oven those of steel under that 

 severe ordeal, as wires of aluminium-bronze. 



Fitness for being made into tubes. It admits of every process necessary for this 

 purpose. 



Specific Gravity. The specific gravities of alloys of aluminium and copper are : 



8 per cent, of aluminium ..... 8-601 



4 ..... 8-621 



6 ..... 8-369 



10 ..... 7-689 



At the Elswick Works Captain Noble, E.A., confirmed previous experiments on tho 

 capability of aluminium-bronze to resist longitudinal and transverse fracture ; and in 

 addition to this ho ascertained that its position to withstand compression stood half- 

 way between that of the finest steel and the best iron. 



The bronze, containing 10 parts of aluminium and 90 of copper, affords an alloy 

 endowed with the greatest strength, malleability, and ductility. The colour of 

 the copper is affected by a very trifling addition of the other constituent, and the 

 alloy gradually improves in these valuable qualities just mentionod, until the 

 proportions given above are reached. After this i.e. when more than 10 per cent. 

 of aluminium enters into the composition of the bronze tho alloy gradually 

 becomes weaker and less malleable, and at length so brittle that it is easily pounded 

 in a mortar. 



CHLORIDE OF. A1 2 C1 8 = 133-9 (A1 2 C1 G ). Preparation. 



Chloride of aluminium cannot be prepared by treating alumina with hydrochloric acid, 

 as in the case of most chlorides ; for on evaporating the solution to dryness, hydro- 

 chloric acid is evolved and alumina alone remains. 



The method at present used is, in principle, tho same as that originally suggested 

 by Oersted, which has since found numerous other applications. It is impossible to 

 convert alumina into the chloride by the direct action of chlorine alone ; at any tem- 

 perature the chlorine is as incapable of displacing the oxygen from the alumina as it 

 would from lime. But if the attraction of tho chlorine for the metal be supported by 

 the affinity of carbon for the oxygen, then the compound is, as it were, torn asunder 

 carbonic acid or carbonic oxide resulting on tho one hand, and tho chloride of alu- 

 minium on the other. 



On the large scale the chlorine is passed over a previously ignited mixture of clay 

 and coal-tar, contained in retorts like those used in the manufacture of coal-gas, 

 which are heated in a furnace ; the chloride, which on account of its volatility is 

 carried off", being condensed in a chamber lined with plates of earthenware, where it 

 is deposited in a crystalline mass. 



Properties. It is a yellowish crystalline solid, readily decomposed by tho moisture 

 of the air into hydrochloric acid and alumina, and volatile at a dull red heat. It is 

 very soluble in water, but cannot be recovered by evaporating the solution. H.M.W. 



Chloride of aluminium has been brought into use as a disinfectant under the name 

 of Chloralum. 



FLUORIDE or. APP (AI'F"). The existence of the 



fluoride of aluminium in nature, in tho form of the double fluoride of sodium and 

 aluminium, namely, 3Na F, APF S (6WaF. A1 2 F), as cryolite, and the use of this 

 mineral in the manufacture of aluminium, have been already alluded to. The fluoride 

 of aluminium likewise exists in several other minerals, namely, the topaz, pycnite, 

 fluellite, chiolite, pachnolite, gearksutito, &c. 



The pure fluoride can only bo obtained artificially by dissolving pure aluminium in 

 hydrofluoric acid. It has a great tendency to form double salts with the fluorides of 

 potassium and sodium. H. M. W. 



ALTTMOCALCITE. A milk-white mineral, from Eibenstock, in Saxony. It 

 appears to be an impure form of opal, containing in addition to the hydrous silica- 

 a notable proportion of lime and alumina. 



AliVA or ALFA. See ESPARTO On ASS. 



ALVITE. A Norwegian mineral, described by Mr. David Forbes and Mr. T. 



