It is believed that enough evidence has been given in this chapter to lead to an appreciation of the assiduous work and practical skill involved in "inventing a system" of lighting that would surpass, and to a great extent, in one single quarter of a century, supersede all the other methods of illumination developed during long centuries. But it will be appropriate before passing on to note that on January 17, 1908, while this biography was being written, Mr. Edison became the fourth recipient of the John Fritz gold medal for achievement in industrial progress. This medal was founded in 1902 by the professional friends and associates of the veteran American ironmaster and metallurgical inventor, in honor of his eightieth birthday. Awards are made by a board of sixteen engineers appointed in equal numbers from the four great national engineering societies--the American Society of Civil Engineers, the American Institute of Mining Engineers, the American Society of Mechanical Engineers, and the American Institute of Electrical Engineers, whose membership embraces the very pick and flower of professional engineering talent in America. Up to the time of the Edison award, three others had been made. The first was to Lord Kelvin, the Nestor of physics in Europe, for his work in submarine-cable telegraphy and other scientific achievement. The second was to George Westinghouse for the air-brake. The third was to Alexander Graham Bell for the invention and introduction of the telephone. The award to Edison was not only for his inventions in duplex and quadruplex telegraphy, and for the phonograph, but for the development of a commercially practical incandescent lamp, and the development of a complete system of electric lighting, including dynamos, regulating devices, underground system, protective devices, and meters. Great as has been the genius brought to bear on electrical development, there is no other man to whom such a comprehensive tribute could be paid. CHAPTER XV INTRODUCTION OF THE EDISON ELECTRIC LIGHT