same current producing only a red heat when the wire, whether of platinum or other metal, is stretched out. ... Failing to obtain satisfactory results from platinum, Edison turned his attention to carbon, the superiority of which as an incandescent illuminant had already been demonstrated; but its rapid consumption, as shown by the Reynier and similar lamps, being unfavorable to its use as compared with the durability of platinum and iridium, the problem was, to secure the superior illumination of the carbon, and reduce or prevent its consumption. As this consumption was due chiefly to oxidation, it was questionable whether the superior illumination were not due to the same cause, and whether, if the carbon were inclosed in a glass globe, from which oxygen was eliminated, the same illumination could be obtained. {776} Another difficulty of equal magnitude was to obtain a sufficiently perfect vacuum, and maintain it in a hermetically sealed globe inclosing the carbon, and at the same time maintain electric connection with the generator through the glass by a metal conductor, subject to expansion and contraction different from that of the glass, by the change of temperature due to the passage of the electric current. Sawyer and Man attempted to solve this problem by filling the globe with nitrogen, thus preventing combustion by eliminating the oxygen. ... The results obtained by this method, which at one time attracted a great deal of attention, were not sufficiently satisfactory to become practical; and Edison and others gave their preference to the vacuum method, and sought to overcome the difficulties connected with it. The invention of the mercurial air pump, with its subsequent improvements, made it possible to obtain a sufficiently perfect vacuum, and the difficulty of introducing the current into the interior of the globe was overcome by imbedding a fine platinum wire in the glass, connecting the inclosed carbon with the external circuit; the expansion and contraction of the platinum not differing sufficiently from that of the glass, in so fine a wire, as to impair the vacuum. ... The carbons made by Edison under his first patent in 1879, were obtained from brown paper or cardboard. ... They were very fragile and short-lived, and consequently were soon abandoned. In 1880 he patented the process which, with some modifications, he still adheres to. In this process he uses filaments of bamboo, which are taken from the interior, fibrous portion of the plant." _P. Atkinson, Elements of Electric Lighting, chapter 8._ ELECTRICITY: A. D. 1854-1866. The Atlantic Cable.