192 
ELECTRO-METALLURGY,—ALUMINIUM. 
lias four holes, two with, stoppers for the introduction of the charge, and two 
open as gas escapes. The anode consists of a bundle of plates of agglomerated 
carbon fixed by a cross-piece, to which is attached the current regulator. The 
upper ends of the plates are engaged in a socket hooked to a chain, which winds 
round a hand-worked windlass. 
The action is continuous, no preparation is required; communication once 
established, the bundle of plates is raised, powdered cryolite is poured through 
the charge-holes and then the plates are lowered. As already stated, the cryolite 
is melted by the current, and the bath is fed with alumina and aluminium fluoride. 
The working is so regulated that the carbon plates shall never be more than L2" 
above the surface of the bath. The current is now of 12,000 amperes. When 
the crucible is full the metal is run out into a carbon-lined mould. The addition 
of the fluoride has lowered the point of fusion and reduced the electromotive 
force from 20 to 10 volts, for its decomposition demands less energy than the 
electrolysis of alumina alone. About 30 horse-power-hours are required to pro¬ 
duce 1 kg. of aluminium. 
In 1891, Neuhausen turned out 200 kg. a day, about one-fifth of the total 
production of the world ; in addition to three tons of aluminium bronze, as well 
as the other alloys manufactured by Cowles. 
The trade aluminium produced has the following composition :— 
Mark. 
No. 0 AIAGr 
„ 1 AIAG- 
„ 2 AIAGr 
Alummium. 
99*9 
99*6 to 99*2 
97‘6 to 92-8 
Silicon. 
0-06 
0T8 to 0-58 
0-94 to 3*82 
Iron. 
0*04 
0T1 to 0-34 
1-37 to 3*34 
WORKS AT FROGES. 
These were the outcome of Neuhausen. Situated in the mountainous country 
of Is ere, at 13 miles from Grenoble, the Societe electro-metallurgique frangaise 
there enjoys a fall of water of about 580', with 88 gallons a second, giving a net 
motive power of 800 horses. 200 yards lower down the stream there is annexed 
an electric carbon factory. 
In 1889 they erected three vertical water-wheels, of which two, with a diameter 
of 8' 6", making 200 revolutions per minute,'and exerting a power of 300 horses, 
were each coupled to a Brown dynamo of 120 kilowatts. The third water-wheel, 
of 100 horse-power, actuates a 2-pole dynamo having a current of 300 amperes 
at 65 volts ; it also works the ventilators of the foundry and the machine tools. 
Above are the water-wheels and the dynamos, then the aluminium furnaces in 
parallel distribution; in the centre is a machine shop ; and_ below that is a 
foundry comprising the furnaces for the second fusion, the moulding shop, the 
laboratory, and the store-rooms. 
Like Neuhausen, Eroges at first only produced alloys of aluminium, now only 
the pure metal, and the alloys are obtained in the second fusion furnaces. 
The furnace (Fig. 5) consists of a sheet-iron cylindrical vat about 22" high and 
24" in diameter. The cover has two holes for admission of the charge and the 
anode respectively. The latter is as in the Kiliani system. Its upper end is 
fixed to a square-threaded screw capable of vertical motion, by means of a hand¬ 
worked mechanism of bevilled-wheels, similar to the raising movement of the 
tool carrier in certain punching machines. The kathode, which is a block of 
copper, passes through the bottom of the vat and rests in a cast-iron socket, 
which is filled with mercury to ensure electrical contact, while a current of water 
plays upon the mercury to hinder its volatilisation. Another plugged hole at the 
bottom of the vat allows for the discharge of the molten metal. 
The charge and the method of procedure are substantially the same as at 
Neuhausen. In 1892, Froges produced daily 100 kg. of aluminium - } for each 
