THOMAS A. EDISON 171 son IlliiTninating Company. In order to be able to fix the charges for the use of the electric light he invented the Edison electric meter. The first office building in which the incan- descent lamp was used was that of the New York Herald. A plant was also installed on the sailing vessel Jeanette, which made a trip in search of the North Pole and was lost in the Arctic regions. The first church to nse the electric light was the City Temple^ London. Soon the industry of furnishing electric light assumed enormous proportions and twenty years after its invention the electric lighting plants in the United States alone were worth $750,000,000. It is doubtful if any other invention has brought about such a revolution in civiliza- tion. It is also probable that Mr. Edison has done more to provide simple and wholesome amusement for the entire human race than any man who ever lived. This he was able to do par- ticularly by inventing the phonograph and the moving picture machine. His earlier experiments with automatic telegraphs had familiarized him with the use of strips having dashes and dots impressed on them and moving rapidly beneath a stylus. Mr. Edison noticed that this stylus in vibrating produced a slight sound. This suggested the talking machine, based upon <the idea of recording the undulations so that when a stylus retraces them a diaphragm may be set in motion, reproducing the original sound. Eventually he made a cylinder upon which the sound waves could be impressed in a spiral line. The phonograph proved to be rather a simple instrument, consist- ing of two parts ; the phonograph and the record. The phono- graph itself was patented February 19, 1878. Mr. Edison made the following prophecy concerning his invention : * * The phonograph will undoubtedly be largely devoted to music — either vocal or instrumental — and may possibly take the place of the teacher. It will sing the child to sleep, tell us what o'clock it is, summon us to dinner, and warn the lover when it is time to vacate the front porch. As a family record it will be precious, for it will preserve the sayings of those dear to us, and even receive the last messages of the dying. It will enable the children to have dolls that really speak, laugh.
