From the dawn of history the two principle agencies for the dissemination of knowledge have been books and communication methods. Once writing was established, its methods of preservation underwent continuous improvement until the invention of printing made the multiplication of books a relatively simple and popular means for the diffusion of knowledge. Yet, other means of communication remained stationary for centuries. The methods available to the founders of the American Republic were substantially the same as those used in Biblical times.
The Nineteenth Century was to witness greater technological advances than any previous period of similar length, and it is not surprising to learn that existing methods of communication were improved and new ones introduced. First, came the semaphore for visual signalling, which reduced the time required for transmitting messages over short distances; then came the electric telegraph to extend the area which could be covered; and finally, came the telephone for the transmission of speech over longer distances. At the close of this century man was enjoying communication facilities undreamed of by the Founding Fathers. There seemed nothing further to discover or invent which would lead to the quickening of transmission or its diffusion over a wider area.
As the century drew toward its close a few scientists were experimenting with the electrical waves which Clerk Maxwell had said could travel through the air with the same speed as light. Maxwell did not produce any such waves, but he said they were there and one day an