Ferro, alumínio, níquel, cobre e prata em Mumford (1934)

Among the metals, electricity places a premium upon those that have a high degree of conductivity: copper and aluminum, Area for area, copper is almost twice as good a conductor as aluminum but weight for weight aluminum is superior to any other metal, even [230] silver, while iron and nickel are practically useless except where resistance is needed, as for example in electric heating. Perhaps the most distinctively neotechnic metal is aluminum, for it was discovered in 1825 by the Dane, Oersted, one of the fruitful early experimenters with electricity, and it remained a mere curiosity of the laboratory through the high paleotechnic period. It was not until 1886, the decade that saw the invention of the motion picture and the discovery of the Hertzian wave, that patents for making aluminum commercially we.re taken out. One need not wonder at aluminum‘s slow development: for the commercial process of extraction is dependent upon the use of large quantities of electric energy: the principal cost of reducing the aluminum ore by the electrolytic process is the use of from ten to twelve kilowatt hours of energy for every pound of metal recovered. Hence the industry must naturally attach itself to a cheap source of electric power. (Mumford 1934:229-30)

MUMFORD, Lewis. 1934. Technique and civilization. New York: Harcourt, Brace and Company.