One day the little child of a station master was playing on the track just as a freight car was moving down toward him. Almost as swift as lightning itself young Edison dashed out, stepped in front of the coming car, and at the risk of his own life snatched the child from danger. In gratitude the station master, knowing the boy's interest in the telegraph, taught him how to use a machine. After that he acquired great skill in this art and operated in many sections of the country, perfecting himself in the subject.
For over twenty years he has had a large establishment, with an immense workshop and many mechanics, at Menlo Park, N. J., where he has devoted his whole attention to inventing. He has perfected his system of duplex telegraphy and invented the carbon telephone-transmitter, the phonograph, the platinum burner, and the carbon burner for the incandescent light. He has patented very many inventions, and his system of electric lighting for houses is now in general use. Edison's whole life is an interesting study for young people.
At the present time the two methods of lighting by electricity are the arc light and the incandescent light. The arc light is used for lighting large buildings like churches, halls, and railway stations, and for lighting the streets of a city. The incandescent light, or the glow-lamp as it is called in England, is in general use for lighting dwelling houses. This lamp consists of a glass bulb from which air has been excluded so that it is almost a perfect vacuum and in which is inserted a looped filament of carbon. The electricity is made to pass through this carbon wire, which is thereby heated to a white heat and thus furnishes the light. Being in a vacuum, the carbon is but slightly burned. It therefore can be subjected to this heat for a long time without breaking or wearing out.
At first Edison used a platinum wire in the little electric lamp. He wanted something better. He needed some form of bamboo or other vegetable fibre. He sent a man to explore China and Japan for bamboo. He sent another, who traveled twenty-three hundred miles up the Amazon River and finally reached the Pacific coast, searching for bamboo. He sent a third to Ceylon to spend years in a similar search. Eighty varieties of bamboo and three thousand specimens of other vegetable fibre were brought him. He tested them all; three or four were found suitable.