Heroult electric steel-making furnace, 1906-1914.

UNITED STATES - SEPTEMBER 19: Model (scale 1:8) of a steel-making furnace designed by Paul Heroult (1863-1914), the inventor of the first direct arc electric steel-making furnace. Heroult's pioneering furnace was invented in 1906, and since then over 450 have been built and used in countries such as America, Russia and Japan. The main advantages of the Heroult furnace is that it allows steel manufacture on a smaller scale than other types of furnace whilst still being economically viable. It also produces substantially less atmospheric emissions than traditional blast furnaces. Heroult was a prolific inventor, and is also credited with devising the electrolytic reduction method for making aluminium from bauxite known today as the Heroult process. (Photo by SSPL/Getty Images)