December 10, 1915] 



SCIENCE 



813 



waves as indicated by the thick wavy curve 

 in Fig. 6, and suppose that these variations 

 follow the law of variation of sound waves 

 in articulate speech, then the man holding 

 a telephone to his ear at the receiving sta- 

 tion B, equipped with a suitable apparatus, 

 will hear articulate speech. This idea is 

 not new; I disclosed it in 1902 to Professor 

 Henry Perkins, of Trinity College, Hart- 

 ford, and I consider the idea as obvious. 

 But what I do not consider as obvious is 

 the manner in which a huge generator of 

 electrical power can be made to vary the 

 power which it delivers in that most com- 

 plicated way which we human beings prac- 

 tise when we vibrate our vocal cords in 

 order to produce articulate speech. When 

 the "Western Electric Company and the 

 American Telephone and Telegraph Com- 

 pany transmitted articulate speech between 

 Arlington and Honolulu they actually con- 

 trolled by the human voice the operation of 

 a huge electrical generator generating many- 

 horse power, and it is plain that the same- 

 method can be easily extended so as to con- 

 trol any amount of power by the human 

 voice. It is, indeed, a great achievement. 

 It may be claimed that the achievement is 

 nothing startlingly new, for do we not know 

 that with a tiny spark we may start a huge 

 explosion and do we not see every day that 

 the chauffeur by minute twists of his hand 

 or foot can regulate the power of the gas en- 

 gine in our automobiles ? Yes, I admit that 

 there is a resemblance, but the resemblance 

 is a very coarse one. When you find a 

 chauffeur who can regulate the movement 

 of his car in such a way that it will vibrate 

 in accordance with the vibrations of articu- 

 late speech, then that chauffeur will have 

 accomplished the same thing which the 

 operator at the Arlington Station did when 

 by the controlling action of his voice he 

 made his huge generator speak the words 

 which were heard at Honolulu, five thou- 



sand miles away. And yet the achievement 

 is perhaps not quite as new as it might 

 appear. When a Paderewsky with Bee- 

 thoven's Sonata in his head makes Bee- 

 thoven's ideas control the strenuous move- 

 ments of his body which agitate the strings 

 of the piano, then I see something which 

 the operator at Arlington might have been 

 unconsciously copying. I throw this out as 

 a suggestion to the biologists, the physiol- 

 ogists, and the neurologists, who are not 

 always aware of what is going on in other 

 departments of physical science, just as we 

 physicists are often totally ignorant of the 

 great researches in biology, physiology and 

 neurology. 



Let us now turn our attention to the elec- 

 trical waves which carried that articulate 

 message from Arlington to Honolulu andl 

 examine their condition when they arrived' 

 at Honolulu. These waves were so feeble 

 that no electrical instrument ever invented! 

 by man could, unaided, ever detect their 

 presence. This brings me to a point which 

 I discussed before this academy just four 

 years ago. I told you then that I had dis- 

 covered an electrical machine which stimu- 

 lated by a feeble electrical wave of high 

 frequency would reproduce that wave magni- 

 fied to any extent. I believe that in that 

 discussion was the first mention of the elec- 

 trical "amplifiers" which play a most im- 

 portant part to-day in wireless transmission. 

 It is far from me to claim the whole credit 

 for the work which has been done in this 

 direction; on the contrary, most of the 

 credit for developing the idea of electrical 

 amplifiers of to-day and of giving them a 

 thoroughly fool-proof form belongs to the 

 research laboratory of the General Electric 

 Company and of the American Telephone 

 and Telegraph Company, and I cheerfully 

 congratulate them upon the wonderful 

 achievement. 



Now what is an amplifier of these high 

 frequency electrical waves ? Broadly speak- 



