National Geographic : 1947 Mar
Birthplace of Telephone Magic ( National Geographic Society Ektachrome by Willard I. ('ulver New Metal for Trial in Telephone Magnets Is Poured from "Self-heating" Furnace Glowing golden at a temperature of 2 ,9 00° F., an experimental alloy of cobalt, nickel, and aluminum is run into a mold. Heating in the furnace is done by the induction process, in which electric current is generated in the metal. Resistance to the current's passage raises the metal's temperature to the melting point.