Page:Heroes of the telegraph (IA cu31924031222494).djvu/192

 success in this important work. He published more than one treatise on the subject at Washington, and it is, we believe, mainly through his efforts that thousands of deaf mutes in America are now able to speak almost, if not quite, as well as those who are able to hear.

Before he left Scotland Mr. Graham Bell had turned his attention to telephony, and in Canada he designed a piano which could transmit its music to a distance by means of electricity. At Boston he continued his researches in the same field, and endeavoured to produce a telephone which would not only send musical notes, but articulate speech.

If it be interesting to trace the evolution of an animal from its rudimentary germ through the lower phases to the perfect organism, it is almost as interesting to follow an invention from the original model through the faultier types to the finished apparatus.

In 1860 Philipp Reis, as we have seen, produced a telephone which could transmit musical notes, and even a lisping word or two; and some ten years later Mr. Cromwell Fleetwood Varley, F.R.S., a well-known English electrician, patented a number of ingenious devices for applying the musical telephone to transmit messages by dividing the notes into short or long signals, after the Morse code, which could be interpreted by the ear or by the eye in causing them to mark a moving paper. These inventions were not put in practice; but four years afterwards Herr Paul la Cour, a Danish inventor, experimented with a similar appliance on a line of telegraph between Copenhagen and Fredericia in Jutland. In this a vibrating tuning-fork interrupted the current, which, after traversing the line, passed through an electro-magnet, and attracted the limbs of another fork, making it strike a note like the transmitting fork. By breaking up the note at the sending station with a signalling key, the