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THE origin of the invention of the electric arc furnace was in 1808. While experimenting with the new science of electricity, Humphry Davy (1778-1829) (Fig 1) discovered that an arc could be created with a high-voltage electric circuit by bringing the two terminals close together (Hg 2). This arc, which cast a bright light and generated considerable heat, could be struck and maintained at will, and its length and intensity varied within limits determined by the circuit voltage and by the type of terminals. Davy demonstrated the arc at the Royal Institution in London, where his discovery aroused great interest. However, for many years it remained a scientific curiosity as no one found a practical use for it. In addition, a large number of batteries were needed which hindered its further development. The electric furnace had to wait for the invention of the dynamo by Ernst von Siemens (1816-1892) (Fig 3) in 1866.
In 1878, Ernest's younger brother Wilhelm Siemens (1823-1883) (Fig 4) used the electric arc for melting scrap steel in a closed hearth. In 1879 he demonstrated the arc furnace he invented to members of the Iron and Steel Institute at Siemens Brothers Charlton Works in London by melting a batch of 2kg of steel scrap in about 20 minutes.
At this early date the available electric power...