(3N PROIESSOR BELl's ARTICULATING TELEPHONE. 1 89 



Perhaps the most interesting part of this extremely simple, but 

 none the less wonderful invention, is the manner in which Prof. 

 Graham Bell arrived at it. Time will not, I fear, permit me to 

 do more than give a very brief sketch of this, — which I had the 

 advantage of hearing in the course of conversation with him. 



Professor Bell, whom we are proud to claim as an Englishman, 

 is the Director of a large College in the United States, where 

 persons are trained in the methods of teaching deaf mutes to 

 speak, by the system known as **" visible speech.'' The first 

 idea of this system was due to his father, A. M. Bell, of Edinburgh, 

 the inventor of a universal alphabet, consisting of only lo 

 physiological symbols, for representing the action of the vocal 

 organs, by combinations of which, all possible vocal sounds can 

 be written down, and reproduced from the symbols by those 

 acquainted with the alphabet. The application of this alphabet to 

 teaching deaf mutes to speak, is due to Professor Graham Bell him- 

 self. In the course of his experiments he devised several methods 

 of exhibiting optically the vibrations of sound, commencing with 

 Koenig's manometric capsule, in which sounds spoken to the 

 instrument temporarily alter the shape of a gas flame. The 

 phonautograph of Leon Scott was then tried, and tracings 

 corresponding to the various vowel sounds were obtained upon 

 smoked glass. The membrane and bones of a human ear were 

 then used, and a stylus of hay being attached to them, much better 

 tracings were obtained. 



Concurrently with these experiments. Professor Bell was engaged 

 in repeating some experimental researches of Helmholtz on the 

 analysis and synthesis of vowel sounds, in which several tuning- 

 forks of different pitch were made to vibrate simultaneously by 

 means of an electric current, and for this purpose he was led to 

 study electro-telegraphic phenomena very closely. Having these 

 separate investigations in his mind at the same time. Professor 

 Bell conceived the idea that a membrane to which a piece of iron 

 was attached, might, by sound, be made to vibrate that iron in 



