408 WORKMEN AND HEROES metal that requires a high temperature to melt, because in practice it was found that in fact, owing to the difficulty of regulating the flow of the electric current, the medium did often melt. He therefore sought for a medium that should be practically indestructible, and believed that it would be found in pure carbon en- closed in a vacuum. After many trials with one and another substance, he at length found that by employing slender strips of card-board reduced by intense heat to carbon, connecting them with the wires leading from the machine, and enclosing them in glass bulbs from which the air had been extracted, the desired result could be produced. The next step to accomplish was the division of the light, so that any number of lamps could be supplied by the same pair of wires a condition absolutely necessary if the invention were to be of practical utility as applied to the lighting of factories, public buildings, or private households, where- ever, in short, many lights are needed This was finally accomplished, and in De- cember, 1879, an exhibition was given at Menlo Park of a complete system of lighting. This first demonstration of the possibility of light-division created a great interest in scientific circles all over the world, especially as scientific experts had testified before the British House of Commons that the feat was impossible. The Edison incandescent burner is now in use in every city, town, and hamlet in this country, and it would seem as if it must of necessity before long drive the costly, unhealthy, and dangerous coal-gas out of use for illuminating purposes, although we believe a wide field of usefulness lies before the coal-gas as a substitute for coal in our kitchens. Thomas Edison has received few public honors from his countrymen ; but the nature of his work has been such as to make his name a household word through- out his native country ; and not only by the admiration excited by his genius for it deserves no less a name but by the practical, every-day benefits he has conferred, he has earned a place in the good-will and esteem of his fellows such as seldom falls to the lot of man. <^7~v~A er
