170 FAMOUS LIVING AMERICANS assistance of Mr. Charles Bachelor, he put the thread in a bulb, exhausted the air and turned on the current. The result was satisfactory in so far as obtaining a good light was concerned but the carbon was not strong enough. Mr. Edison, however, realized that he was on the right track so far as the carbon filament was concerned, but he must make his filament from some other substance. He next took a spool of cotton thread and tried to carbonize the thread, but it broke again and again. He was not disheartened, however, but kept up the battle for two days and two nights. On the night of the third day, after beginning the experiment with carbonized cotton, Mr. Edison and Mr. Bachelor placed the filament in the lamp, exhausted the air and turned on the current. In a moment they realized that their efforts had at last been crowned with complete success, for a beautiful, soft light could now be seen. The cotton thread lasted for about forty hours. They next tried to find some sort of material which would give a light that would last much longer, and so they began car- bonizing almost every material they could lay their hands on, such as straw, paper, and cardboard. The best results were obtained with bamboo, which Mr. Edison had obtained by tear- ing to pieces a bamboo fan. He now sent men to all parts of the world to find the best sort of bamboo, spending fully a hundred thousand dollars in the search. Some of his helpers went to the Malay peninsula ; others to Mexico, Ceylon, India. Almost six thousand different kinds of fibrous plants were tried, the most satisfactory growing in the valley of the Ama- zon. Having at last solved the difficulty of obtaining the right sort of filament, Mr. Edison took out a patent for his electric light in January, 1880. He tested out his lights by stringing up a number of them along a wire suspended from the trees in Menlo Park, and invited his friends to come and see the new system of lighting. Among the visitors were the New York Board of Alderman, who went to Menlo Park on a special train and were delighted with the new invention. Mr. Edison next turned his mind to the task of establishing a central station in New York City from which the electric light could be obtained, and then organized the New York-Edi-
