ON SOME MARVELS IN TELEGRAPHY. 263 



Van der Weyde, of New York, states that, after reading an 

 account of Reuss's telephone, he had two such instruments 

 constructed, and exhibited them at the meeting of the Poly- 

 technic Club of the American Institute. "The original 

 sounds were produced at the furthest extremity of the large 

 building (the Cooper Institute), totally oujt of hearing of the 

 Association ; and the receiving instrument, standing on the 

 table in the lecture-room, produced, with a peculiar and 

 rather nasal twang, the different tunes sung into the box at 

 the other end of the line ; not powerfully, it is true, but very 

 distinctly and correctly. In the succeeding summer I 

 improved the form of the box, so as to produce a more 

 powerful vibration of the membrane. I also improved the 

 receiving instrument by introducing several iron wires into 

 the coil, so as to produce a stronger vibration. I submitted 

 these, with some other improvements, to the meeting of the 

 American Association for the Advancement of Science, and 

 on that occasion (now seven years ago) expressed the opinion 

 that the instrument contained the germ of a new method of 

 working the electric telegraph, and would undoubtedly lead 

 to further improvements in this branch of science." 



The telephonic successes recently achieved by Mr. Gray 

 were in part anticipated by La Cour, of Copenhagen, whose 

 method may be thus described : At the transmitting station 

 a tuning-fork is set in vibration. At each vibration one of 

 the prongs touches a fine strip of metal completing a circuit 

 At the receiving station the wire conveying the electric cur- 

 rent is coiled round the prongs of another tuning-fork of the 

 same tone, but without touching them. The intermittent 

 current, corresponding as it does with the rate of vibration 

 proper to the receiving fork, sets this fork in vibration ; and 

 in La Cour's instrument the vibrations of the receiving fork 

 were used to complete the circuit of a local battery. His 

 object was not so much the production of tones as the use 

 of the vibrations corresponding to different tones, to act on 

 different receiving instruments. For only a fork correspond- 

 ing to the sending fork could be set in vibration by the 



