224 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1907. 
with suitable slags. When purified, “ carburite ” in requisite amount 
is added, and the crucible is tipped. 
Heroult claims that with this furnace iron or steel of any degree 
of impurity can be refined, and that from the purified metal, a steel 
of any desired composition can be produced by the addition of the 
necessary amount of “ carburite ” and other ferro-alloys. 
The Heroult furnace is now in operation at La Praz and Froges 
in France, at Kortfors in Norway, at Remscheid in Germany, and 
at Syracuse, New York. The Remscheid plant has been in operation 
since February, 1906, and is on a smaller scale than the Syracuse plant. 
SS 
Pia. 5.—Longitudinal and transverse sections of Héroult crucible furnace. 
The Kjellin furnace has been developed at Gysinge in Sweden, and 
differs materially from the Heroult furnace. In place of the use of 
direct current for combined are and resistance heating, the Kjellin 
process utilizes induced currents, and the heating effect is obtained by 
the rapid changes in the magnetic state of the iron or steel which 
forms the secondary coil of the circuit. The Kjellin furnace is in 
reality a large transformer, in which an alternating current of low 
amperage, but high voltage, is transformed into an alternating current 
