It is said that even a whisper can in this way be reproduced at a distance, the maximum extent of which may possibly be much greater than has yet been achieved. At one of the exhibitions given to illustrate this system, Professor Bell stationed himself in the Lyceum at Salem; Mr T. A. Watson at Boston. An intermittent current, sent through the eighteen miles of telegraphic wire, produced in the telephone a horn-like sound. The Morse alphabet was then transmitted in musical sounds, audible throughout the lecture-hall. Then the sounds of an organ were made to act upon the apparatus, and these in like manner were transmitted; two or three tunes being distinctly heard in succession at Boston. Professor Bell then signalled to Mr Watson to sing a song; this was done, and the words as well as the tune of the song heard. A speech was then made at Boston in the simple words: 'Ladies and gentlemen, it gives me great pleasure to be able to address you this evening, although I am in Boston and you in Salem.' This speech was heard distinctly in the Lyceum at Salem, and was followed by many questions and answers sent to and fro. If monotones be adopted instead of those variations in pitch which belong to ordinary music, it is believed that several telephonic messages may be sent through the same wire at the same time. It would be agreed on beforehand that all sounds in C (for instance) shall be intended for one station alone; all those in D for another station, and so on; each diaphragm would vibrate in the manner belonging to the sound-waves impinging upon it; but each station would attend only to those in a particular pitch. Such is the theory. Whether it can be practically carried into effect, the future must shew. Mr Cromwell Varley, during his researches in duplex telegraphy, produced an apparatus which he is now trying to apply to telephonic purposes. A limited amount of success was achieved in July of the present year, through an electric wire connecting two concert-halls in London; but the apparatus requires further development. It comprises among other details a series of tuning-forks, one for each note.