It is now well known that the phenomenon called sound consists of a wave agitation communicated through the particles of some medium to the organ of hearing.  Every particular sound has its own physical equivalent in the system of waves in which it is written.  The only thing, therefore, that is necessary in order to carry a sound in its integrity to any distance, is to transmit its physical equivalent, and to redeliver that equivalent to some organ of hearing capable of receiving it.

Upon these principles the telephone was produced—­created.  Every sound which falls by impact upon the sheet-iron disk of the instrument communicates thereto a sort of tremor.  This tremor causes the disk to approach and recede from the magnetic pole placed just behind the diaphragm.  A current of electricity is thus induced, pulsates along the wire to the other end, and is delivered to the metallic disk of the second instrument, many miles away, just as it was produced in the first.  The ear of the hearer receives from the second instrument the exact physical equivalent of the sound, or sounds, which were delivered against the disk of the first instrument, and thus the utterance is received at a distance just as it was given forth.

As already said, the invention of the telephone stands chiefly to the credit of Professors Gray and Bell.  It should be recorded that as early as 1837, the philosopher Page succeeded, by means of electro-magnetism, in transmitting musical tones to a distance.  It was not, however, until 1877 that Professer Bell, in a public lecture given at Salem, Mass., astonished his audience, and the whole country as well, by receiving and transmitting vocal messages from Boston, twenty miles away.  Incredulity had no more a place as it respected the feasibility of talking to persons at a distance.  The experiments of Gray at Chicago, a few days later in the same month, were equally successful.  Messages were distinctly delivered between that city and Milwaukee, a distance of eighty-five miles, nor could it be longer doubted that a new era in the means of communication had come.

The Bell telephone, with its many modifications and improvements, has come into rapid use.  Within reasonable limits of distance, the new method of transmitting intelligence by direct vocal utterance, has taken the place of all slower and less convenient means of intercommunication.  The appearance of the simple instrument has been one of the many harbingers of the oncoming better time, when the interchange of thought and sentiment between man and man, community and community, nation and nation, and race and race shall be the preliminary of universal peace in the world and of the good-fellowship of mankind.

Every such fact as the invention of the telephone, produces a complex and almost indescribable result in human society.  This result has in it, in the first place, a change in the manners and method of the individual There is also a change in his sentiments.  He whose work in life, whatever it may be, is accomplished in touch with the telephone will realize that he is in touch with the whole world.  This intimacy reaches, first, his neighbors and friends.  He seems to live henceforth in their presence, and in communication with them.