The Bell System Technical Journal 



January, 1926 



Joseph Henry 

 The American Pioneer in Electrical Communication 



By BANCROFT GHERARDI and ROBERT W. KING 



IN the brilliant galaxy of investigators to whom we owe our 

 knowledge of electrical science, Joseph Henry stands out as of 

 the first magnitude; aad for those who are associated with the Bell 

 System, the present is a most appropriate time to review his researches 

 which had an important guiding influence on the development of 

 electrical communication. The present year marks the fiftieth since 

 the invention of the telephone by Alexander Graham Bell, and among 

 the scientists with whom Bell conferred at that time, he gave a place 

 of honor to Henry. In a letter to his parents written in March, 1875, 

 while he was busy in an effort to perfect the harmonic telegraph, 

 and before he had turned his attention to the telephone, Bell wrote: 



"Now to resume telegraphy. When I was in Washington, I had 

 a letter of introduction to Professor Henry, who is the Tyndall of 

 America. I had found on inquiry at the Institute of Technology, 

 that some of the points I had discovered in relation to the applica- 

 tion of acoustics to telegraphy had been previously discovered by 

 him. I thought I would, therefore, explain all the experiments, and 

 ascertain what was new and what was old. He listened with an 

 unmoved countenance, but with evident interest to all, but when I 

 related an experiment that at first sight seems unimportant, I was 

 startled at the sudden interest manifested. 



"I told him that on passing an intermittent current of electricil\' 

 through an empty helix of insulated copper wire, a noise could be 

 heard proceeding from the coil, similar to that heard from the tele- 

 phone. He started up, said, 'Is that so? Will you allow me, Mr. 

 Bell, to repeat your experiments, and publish them to the world 

 through the Smithsonian Institute, of course, giving you the credit 

 of the discoveries?' 



"I said it would give me extreme pleasure, and added that I had 

 apparatus in Washington, and could show him the experiments myself 

 at any time. . . . 



"We appointed noon next da\" for the experiments, I set the in- 



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