ALUMINIUM, CHL01UDK OF, 



AMALGAM. 



M 



If, however, the chloride i* to be at once employed for the preparation 

 of the metal, it i* better to conduct the rapour from the neck of the 

 retort over ignited chloride of sodium, by which the double chloride of 

 aluminium and sodium i* produced. For the preparation of aluminium, 

 400 parts of this double salt are mixed with 200 part* of chloride of 

 odium and 200 part* of fluor spar (fluoride of calcium), all perfectly 

 dry and in fine powder. This mixture is then placed in a crucible, 

 intentratified with 75 to 80 part* of sodium : the whole being covered 

 with a layer of powdered chloride of sodium. The crucible i* heated 

 at fint gently, until the sodium begin* to act, and afterward* to the 

 malting point of the materials, which are to be stirred about with a 

 porcelain rod and then poured out into a convenient mould. The 

 cooled ma** will contain a regulus of about 20 part* of aluminium, and 

 a further quantity of about 6 part* in small globule*. The reduction 

 of chloride of Aluminium by sodium may be thu* expressed : 



A1.C1, + SXa = Al, + SNaCl. 



Chloride of Sodium. Aluminium. Chloride of 

 aluminium. sodium. 



Earthenware crucibles lined with a mixture of lime and alumina are 

 used for the reduction. 



I'rvolytc, a native double fluoride of sodium and aluminium 

 + A1,F.), ha* been also used in a similar manner by Percy and 

 Roue for the preparation of aluminium. 



Aluminium thus prepared is a blueish-white metal, of a lustre 

 inferior to silver. When cast, it is as soft a* pure silver, and baa a 

 specific gravity of 2'56, about equal to the lightest descriptions of glass. 

 By hammering and rolling, it becomes nearly as hard as iron, and has 

 then a specific gravity of 2'67. Its melting point lies between those of 

 zinc and silver. It is slightly magnetic, and conduct* electricity eight 

 time* better than iron. Exposed to the air it does not oxidise, even at 

 a red heat, and may be placed in contact with boiling water for any 

 length of time without undergoing change. Dilute or concentrated 

 nitric acid do not act upon it in the cold, and even concentrated boiling 

 nitric acid dissolves it only with extreme slowness. On the other hand, 

 dilute hydrochloric acid and solutions of fixed alkalies readily act upon 

 and dissolve it, with the evolution of hydrogen. It is not tarnished 

 like silver by sulphuretted hydrogen, and does not amalgamate with 

 mercury by simple contact. It can be wrought with about the same 

 ease a* silver, and has already been used to a considerable extent by 

 the silversmith and jeweller. In beauty of surface it is inferior to 

 silver, but its extraordinary lightness and permanency in the air will 

 probably lead to its employment for articles in which these qualities 

 are a desideratum. 



ALUMINIUM, CHLORIDE OF. [ALUMINIUM.] 



ALUMINOUS CAKE, an impure sulphate of alumina, recently 

 patented by Mr. Pochin, and which is now employed to a considerable 

 extent a* a substitute for alum in the preparation of mordants and in 

 the manufacture of paper. It i* prepared by gently calcining china 

 clay, selected as free from iron as possible, and then when cold mixing 

 it with concentrated sulphuric acid in a leaden vat. A coil of leaden 

 pipe i* placed at the bottom of the vat, and steam passed through the 

 former until the sulphuric acid begins to act upon the clay. The hot 

 mixture is then run into a shallow flag vat with moveable sides ; here 

 the action becomes every moment more violent, torrent* of steam are 

 evolved from innumerable little craters, and finally, the mixture 

 solidifies to a hard, honey-combed, grayish-white mass, which consist* 

 almost entirely of silica and sulphate of alumina. When this mag* ia 

 treated with water, the sulphate of alumina dissolves, whilst the silica 

 remain* behind in an insoluble condition. The following analysis shows 

 the composition of aluminous cake : 



Alumina (a* soluble sulphate) . . . 13'44 



Peroxide of iron (as soluble sulphate) . . - 26 



Insoluble basic sulphate of alumina . . 2'99 



Soluble silicic acid -01 



InsoluMe xilicic acid ..'... 18'70 



Insoluble alumina (as silicate) . . . . 3'38 



Sulphuric acid (in KoluMc KiilpluvU-s> . . 82'81 



Sulphate* of soda anil potash . . . . -87 



l.imo -50 



' .. 



Water 27-04 



100-00 



As the milpliAto of alumina i* the only ingredient in nltim which is 

 made uso of in nearly all the proceese* to which the latter salt is applied, 

 it follow* that oliiminoiui cake may be effectively substituted for alum, 

 whilst, being considerably cheaper and containing a larger proportion of 

 alumina, it* \ue in more economical 



AI.I'MS. A name applied by chemists to an im|irUnt clan o) 

 salt*, to which commercial ammonia alum and potash alum belong. 

 The alum* ore essentially double salts, consisting of an alkaline sulph.it . 

 < .nibined with the sulphate of a Kewpiioxide base, and crystallising 

 generally in octohnlmn* with twenty. four atoms of water. 



The following are the principal salts belonging to this class : 



Potart alum 

 Ammonia alum 

 Soda alum . 



Iron alum . 

 MamranrM alum 

 Chrome alum 



KO, 80, + Al.O,, ISO, + 14 aq. 

 (SH.)O. 80, + Al.O,, ISO, + 14 aq. 

 NaO, SO, -I- Al,0, t ISO, + 14 aq. 

 KO, 80, + Fe,0,, ISO, + 14 aq. 

 ', + Mn,0,.>SO, + 14 aq. 

 KO, SO, + Cr.O,, S80, + 14 aq. 



AMAI.T.KITKS. a nation who dwelt RW. of Palestine, between 

 Edom and Egypt, (Gen. xiv. 7; Exod. xvii. 8 16; 1 Sam. xv. 7.) 

 According toJoeephunCAutitiuities.'iii. 2), those whodwclt in Oobolitis 

 and IVtra were called Amok-kites, and were the most warlike among 

 the surrounding nation*. He calls their country Amalvkitia, and 

 describe* it a* a pert of Idimuca. (' Antiq.' ii. 1.) Joaephus aUo calls 

 the country of Midian Amalekiti*, and says that it was situated between 

 IVlusium, on the border* of Egypt, and the Red Sea. ( Antiq.' 

 *. 8, and ch. 8.) It appear* al*o that they occupied several place* in 

 Palestine among the C'anaanitea, and in the land of Ephraim we find a 

 mountain of the Amalekite* where Abdon, the son of Hillel, was buried 

 in 1 'ii.it In 'ii. 



Thu Amalekites were the first who opposed the Israelites on their 

 march from Egypt. (Exod. xvii. S 18; Jos. ' Anti>i.' iii. 2.) They 

 suffered great loss, but were afterward* assisted by the Canaanites, and 

 obtained a great victory. (Num. xiv. 89 45.) During the time of the 

 Judges, the Israelite* were frequently oppressed by the Amalekite*, 

 Ammonite*, and Midianite*. (Judge* iii. 13; vi. 3 ; Joseph, v. 7 ' 

 Saul fought with the Amalekites, and took their king Agag alive, 

 who was cut to pieces by the prophet Samuel (1 Sam. xv. ; Jos. 

 Aiui.|.' vi. 8.) lt.iv id warred against them (1 Sain, xxvii. 8); and 

 therefore the Amalekite* plundered the town of Ziklag, and set it on 

 fire, but David overtook them in the wilderness and recovered all that 

 they had carried away. (I Sam. xxx. 18 ; 'Antiq.' vi. 15.) The Amale- 

 kites were finally extirpated by the Simeonite*, who occupied their 

 country during the reign of Hexckiah (1 Chron. iv. 43), and this is the 

 last notice of them. Thus, according to the direction of Moses, the 

 remembrance of Amalek was blotted out from under heaven, became 

 they slew the hindmost of the Israelite* who fainted in the wilderness. 

 (l)eut. xxv. 17, 19.) Jogephu* says that Hainan, called in the !> 

 K-thir on Agozite, was an Amalekite. Le Clerc, Hengstenberg, and 

 others, assert that there wo* more than one tribe of Amalekites, an 

 opinion founded chiefly on the difference of their localities : but the 

 Bible narrative makes no distinction, and their national character, that 

 of a warlike and jiastoral race, will account for their dispersion. 



AMALUAM, a compound of two or more metals, of which one is 

 always mercury; and this circumstance distinguishes an amnl : i,im 

 from a mere ///. Nature presents us with only one amalgam, which 

 is of silver, and is termed by mineralogists natire amah/am : it occurs 

 in Hungary, Sweden, &.C., and is met with either semi-fluid, massive. < 

 crystallised in rhombic dodecahedrons. Klaproth found it to consist 

 of 64 parts of mercury and 86 of silver in 100 parts. Most metals 

 may be amalgamated with mercury, and the combination appears to 

 depend on chemical affinity. When the cohesion of a metal is slight, 

 as in the cases of potassium and sodium, or when its affinity for mercury 

 is considerable, an in the instance* of gold ami silver. amalgamation takes 

 place readily by mere contact. When, on the other hand, the cohesion 

 of a metal is strong, or it* affinity for mercury is weak, heat, or inter- 

 mediate action, or both, are requisite to effect amalgamation. 



There ore several circumstance* which show that amalgamation is 

 the result of chemical affinity ; the crystalline form of the native 

 amalgam is strongly indicative of it, and it is confirmed by analysis ; 

 for if the quantities of mercury and silver were 64 of the former and 

 34'56 of the latter metal, instead of 36, as alxive mentioned, they would 

 in' in tin' proportions of 200 to 108, or 1 atom of each. 



The phenomena also which accompany the action of mercury upon 

 other metals evince its chemical nature : if 44 jiarU of mercury l>e 

 mixed with 1 part of potassium, combination occurs with the evolution 

 of much heat, and when the resulting amalgam is cold, it is hai 

 has the appearance of silver. When the quantity of mercury . 

 100 parts to 1 part of potassium, the compound is liquid; and an 

 amalgam containing only 1'5 per cent, of potassium i* osoeptibl* of 

 crystallising. The density of an amalgam exceeds that of the mean of 

 tin- metal.'. 



There are some metals, it has been already observed, which require 

 heat in order to amalgamate them ; of these antimony offers an ex- 

 ample. In order to effect coml<in.itin it must be melted, and while 

 li.piid mixed with hot mercury. Merc heat, however, cause* no action 

 between iron and mercury. It has been stated, however, that they 

 may be amalgamated l>y mixing the filings of the metal with powdered 

 alum, and ruMiing them together in a mortar with a little water : after 

 trituration the alum may be washed out ; but an amalgam of iron may 

 beat be formed )>y ruhliir r metal with an amalgam of sodium. 



By the intervention of tin or /inc. iron may be combined with imi- 

 curcy, ami a double amalgam is formed. I'latinum also unites with 

 mercury by the intervention of the amalgam of potawium or sodium. 

 but not by direct action. Many metals otherwise difficult to amal- 

 gamate, such as iron, platinum, and aluminium, may be combined 

 with mercury when placed in contact with the latter metal in acidu- 



