Masterpieces of Science 



It was always my belief that a certain ratio 

 would be found between the several parts of a tele- 

 phone, and that the size of the instrument was 

 immaterial ; but Professor Peirce was the first to 

 demonstrate the extreme smallnessof the magnets 

 which might be employed. And here, in order 

 to show the parallel lines in which we were work- 

 ing, I may mention the fact that two or three 

 days after I had constructed a telephone of the 

 portable form (Fig. 12), containing the magnet 

 inside the handle, Dr. Channing was kind enough 

 to send me a pair of telephones of a similar 

 pattern, which had been invented by experi- 

 menters at Providence. The convenient form 

 of the mouthpiece shown in Fig. 1 2 , now adopted 

 by me, was invented solely by my friend, Pro- 

 fessor Peirce. I must also express my obliga- 

 tions to my friend and associate, Mr. Thomas A. 

 Watson, of Salem, Massachusetts, who has for 

 two years past given me his personal assistance 

 in carrying on my researches. 



In pursuing my investigations I have ever had 

 one end in view the practical improvement of 

 electric telegraphy but I have come across 

 many facts which, while having no direct bearing 

 upon the subject of telegraphy, may yet possess 

 an interest for you. 



For instance, I have found that a musical tone 

 proceeds from a piece of plumbago or retort 

 carbon when an intermittent current of electric- 

 ity is passed through it, and I have observed the 

 most curious audible effects prodticed by the 

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