either alone or conjointly with carbon or hydrogen. The operation is effected in an apparatus similar to a Bessemer converter, divided into two compartments. In one of these compartments is placed melted iron, or an alloy of iron, which is made to run into the second by turning the converter. This last compartment has two tuyeres, one of which serves to introduce hydrogen, while by the other is introduced either A12C16, A12F6, Al2C1o.2NaCl, or Al2F6.6NaF, in liquid or gaseous state. In presence of the hydrogen the iron takes up chlorine or fluorine, chloride or fluoride of iron is disengaged, and aluminium mixed with carbon remains as a residue. Then this mixture of iron, aluminium, and carbon is returned to the other compartment where the carbon is burnt out by means of a current of air. The mass being then returned to the chamber of reduction, the operation described is repeated. When almost all the iron has been consumed, the reduction is terminated by hydrogen alone. There is thus obtained an alloy of iron and aluminium. (The preparation of sodium does not require the intervention of hydrogen. A mixture of iron with an excess of carbon and caustic soda, NaOH, is heated in the converter, when the sodium distils off* When all the carbon has been burnt, the iron remaining as a residue may be converted into Bessemer steel. As iron forms an alloy with potassium, the method

* Compare with p. 141.

would scarcely serve for the production of that metal.) To obtain the pure aluminium, sodium is first prepared by the process indicated, the chloride or fluoride of aluminium is introduced into the apparatus in the other chamber, when the metal is reduced by the vapor of sodium. The chambers ought to be slightly inclined, and an agitator favors the reaction. The inventor intends to apply his process to the manufacture of magnesium, strontium, calcium, and barium.

Calvert and Johnson* made experiments on the reduction of aluminium by iron, and the production thereby of iron-aluminium alloys. We give the report in their own words:

"We shall not describe all the fruitless efforts we made, but confine ourselves only to those which gave satisfactory results. The first alloy we obtained was by heating to a white heat for two hours the following mixture:—

"The lime was added to the mixture with the view of removing the chlorine from the Al2C1o, so as to liberate the metal and form fusible calcium chloride, CaCl2. Subtracting the lime from the above proportion, we ought to have obtained an alloy having the composition of 1 Equivalent Al

* Phil. Mag., 1855, x. 240.

to 5 Equivalents of Fe, or with 9.09 per cent. aluminium. The alloy we obtained contained 12 per cent., which leads to the formula AlFe1. This alloy, it will be noticed, has an analogous composition to the one we made of irou and potassium, and like it was extremely hard, and rusted when exposed to a damp atmosphere. Still it could be forged and welded. We obtained a similar alloy by adding to the above mixture some very finely pulverized charcoal and subjecting it to a high heat in a forge furnace for two hours. This alloy gave on analysis 12.09 per cent.* But, in the mass of CaCl2 and carbon remaining in the crucible there was a large amount of globules varying in size from a pin head to a pea, as white as silver and extremely hard, which did not rust in the air or in hyponitric fumes. Its analysis gave 24.55 per cent. aluminium; the formula Al Fe3 would give 25 per cent. Therefore this alloy has the same composition as Al2O3, iron replacing oxygen. We treated these globules with weak sulphuric acid, which removed the iron and left the aluminium, the globules retaining their form, and the metal thus obtained had all the properties of the pure aluminium.

"We have made trials with the following mixture, but, although they have yielded results, still they are not sufficiently satisfactory to describe in

* In the original paper it is given as 12.09 per cent. iron. The inference is unavoidable that this was a misprint, but it is not corrected in the Errata at the end of the volume.

this paper, which is the first of a series we intend publishing on alloys. This mixture was :

"From this we obtained a metallic mass and a few globules which we have not yet analyzed."

Fremy: Alloys of aluminium and iron have been prepared by Benzon by calcining a mixture of alumina, carbon, and iron or Fe2O3. (See p. 214.)

Watts: E. L. Benzon* reduces aluminium by heating alumina with the oxide of another metal, as of copper, iron, zinc, or a mixture of alumina with carbon and the other metal in a free state, the materials being all finely divided and mixed in atomic proportions, or rather with the carbon slightly in excess.

M. Evrard,† in order to make aluminium bronze, makes use of an aluminous pig iron. (It is not stated how this aluminous pig iron is made.) This is slowly heated to fusion, and copper is added to the melted mass. Aluminium, having more affinity for copper than for iron, abandons the latter and combines with the copper. After the entire mass has been well stirred, it is allowed to cool slowly so as to permit the bronze, which is heavier than iron, to find its way to the bottom

* Eng. Pat., 1858, No. 2753.

Annales du Genie Civil, Mars, 1867, p. 189.

of the crucible. M. Evrard makes silicon bronze in the same way by using siliceous iron.

'Eng. and Mining Journal,' May 15, 1886: "The iron-aluminium alloy used in the Mitis process, we are informed by Mr. Ostberg, is made in Sweden by the addition of clays in iron smelting, a patented process producing alloys with 7 to 8 per cent. aluminium very cheaply. Mr. Ostberg adds that he purchased a small quantity of Cowles Bros.' alloy, which gave rise to our previous unqualified statement that he used Cowles' alloys." (See 'Mitis Castings,' Part XI.).

REDUCTION WITH COPPER.

Calvert and Johnson* obtained copper alloyed with aluminium by recourse to a similar chemical reaction to that employed to get their iron-aluminium alloy. Their mixture was composed of

"We mixed these substances intimately together, and after having subjected them to a high heat for one hour we found at the bottom of the crucible a melted mass covered with cuprous chloride, Cu2Cl2, and in this mass small globules, which on analysis contained 8.47 per cent. aluminium, corresponding to the formula

* Phil. Mag. 1855, x. 242.