ABSTRACT
During the nineteenth century and the first half of the twentieth century, coal and steel were major factors in determining economic power and consequently political power. Coal was a factor for two reasons: first, as a source of energy (coal remained the principal source of energy in the world until 1955; not until then was it displaced by oil), and second, because transformed into coke and combined with iron ore it is one of the two essentials for making pig iron, then steel. From 1850 until 1950 steel was the basic element of all modern manufacture, and more particularly the manufacture of weapons of all types.
