Gramme arc lamp regulator. Historical illustration of the arc lamp regulator (top) invented by Belgian engineer Zenobe Gramme (1826-1901). The carbon arc lamp (globe at bottom) had been invented at the start of the 19th century, but numerous technical problems had to be solved before the technology could be used commercially. One innovation was the use of electromagnetic regulators to maintain the electric arc as the electrodes burn down. Artwork from 'Electricite' (1911) by Max de Nansouty, part of the 'Les merveilles de la science' series of 1867-1891 by Louis Figuier.