25 



Watson was then asked to make a speech to the audience. 

 He expressed himself as having more confidence eighteen 

 miles away than if he were present. His speech was as 

 follows : "Ladies and gentlemen : it gives me great pleas- 

 ure to be able to address you this evening, although I am 

 in Boston and you in Salem." This could be heard thirty- 

 five feet distant; that is, all over the hall, and brought 

 down the house with applause. A system of questioning 

 was then carried on and Mr. Watson was asked if he 

 heard the applause. The answer was, "I was not listen- 

 ing. Try again." The applause was given and its 

 receipt at once acknowledged in Boston.] 



A number of musical notes can be sent simultaneously 

 on the same circuit, which gives a great advantage. We 

 did not get exactly the same effects as when the musical 

 notes are heard in the air. The cause is not far to see ; 

 for in the intermittent current the vibrations are not in 

 the exact ratio of the vibrations of the air. 



Other experimenters have been trying, Avith myself, 

 to bring to practical effect the principle of multiple elec- 

 tricity. I discovered that when a great number of in- 

 termittent currents were being transmitted one breaks 

 while the other makes, so that there Avas really no break 

 at all. There are six kinds of electrical current. [This 

 subject was then further illustrated by the lecturer upon 

 the blackboaid ; the different forms of the electrical wave ; 

 and the differences between positive and negative elec- 

 tricity ; "direct" and "reversed" "intermittent, pulsatory 

 and undulatory currents" were shown; and how the 

 sound of musical notes may be produced by such currents 

 together.] 



The idea occurred to me of a new kind altogether, and 

 that the current might be made to vary exactly as the air 

 varies. [This idea was then further explained and illus- 



