186 
ELECTRO-METALLURGY.—ALUMINIUM. 
which constitutes this electrode is for the purpose oxidised when issuing from the 
furnace in a molten state, and its oxygen, disengaged by electrolysis, is free to 
oxidise the impurities of the bath. Some of these deposit themselves on the 
anodes in a thin layer of insoluble mud, which falls to the bottom of the vat and is 
automatically withdrawn. Mr. Elmore has devised an ingenious system for the 
direct manufacture by electrolysis of copper weldless tubes. His kathode is a 
hollow mandril of polished steel, tilled with wood, which rotates ; while the 
copper is being deposited on this cylinder, agate rollers pass up and down and 
give to the nascent metal compactness and homogeneity. These compressors 
have an automatic alternating motion like that of a planing machine table, and be¬ 
tween two successive turns a layer of copper of about •0003" is deposited. The 
current has a strength of 180 amperes, which is six times greater than in the 
ordinary method. 
In all the foregoing methods we have treated of products preliminarily purified : 
numerous attempts have been to extract copper from an electrolytic bath prepared 
with ores rudimentally and cheaply treated. In Italy Signor Marchese has suc¬ 
ceeded with a sulphurous ore, melted at first in a cupola furnace, to produce by 
roasting a cupreous mass containing 
Copper . 35 
Iron . .. 38 
Sulphur. 27 
which is run into plates to form the anode. To prepare the bath, a rich ore pre¬ 
viously roasted is treated with sulphuric acid in leaden vessels. The kathode is 
formed as usual of a plate of refined copper. 
MANUFACTURE OF ALUMINIUM. 
H. Sainte-Claire Deville should be considered the creator of the metallurgy of 
aluminium, discovered by Wohler in 1827, and industrially produced for the first 
time by the learned Frenchman in 1854. In a remarkable memoir published in 
1859, which might be believed to have been written yesterday, the practical 
details of the manufacture are indicated in their entirety. Even the methods, 
whence have proceeded the electric processes of 30 years later, are foreseen, and 
all the physical and chemical properties of the new metal are described with 
perfect accuracy. Deville manufactured aluminium at some works at Javel by 
decomposing aluminium chloride with sodium. The chloride was obtained by 
treating pure alumina mixed with its own weight of tar in a gas retort raised to 
a red heat and traversed by a current of dry chlorine. The sodium was produced 
in wrouglit-iron cylinders in a reverberatory furnace from sodium carbonate re¬ 
duced with carbon. He mixed chalk with both substances to render the mass 
less fusible, and to promote the production of vapours of sodium by the gaseous 
current issuing from the decomposed chalk. The temperature on the hearth rose 
to a white heat. The charge was the following:— 
Sodium carbonate. 20 
Carbon . 9 
Chalk . 3 
Aluminium chloride was afterwards replaced by the double chloride of aluminium 
and sodium, which is more stable. This substance was obtained by treating in a 
reverberatory furnace with a current of chloride gas, a mixture of pure alumina 
(extracted from bauxite, a natural silicate of alumina and iron), sodium chloride 
and wood charcoal. These three substances, previously triturated in a dry state 
and intimately mixed, were reduced to a paste with oil, then formed into lumps 
and calcined. The re-action was produced by sodium with cryolite, a natural 
