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Unlike many great inventions, the discovery of the possibility of conveying 

 speech by electrical currents was the result of careful scientific study. In his early 

 telephones Bell started with the idea of analysing sounds into a number of com- 

 ponent parts, transmitting the components and recombining them, when they 

 were received, into the spoken word. He regarded as one of his greatest dis- 

 coveries the fact that one of the reeds in his "harp" transmitter produced a current 

 of sufficient power to excite vibrations in another " harp " which had a reed tuned 

 to the same note as that which produced the original current. The substitution 

 of a membrane for the reeds was the next step, and led to the first practical 

 telephone, through which he and his assistant, Air. Watson, shouted to each other. 

 Such is the story, in brief, told in the first chapters of Mr. Kingsbury's book. It 

 is one of the most fascinating stories that is to be found in the whole history of 

 discovery and invention, a story which brings out most clearly the genius of Bell 

 and his extraordinary acumen and power of observation. 



Next follows an account of the inception of the telephone exchange, which 

 began with the application to telephonic purposes of the district telegraph system 

 installed originally as a protection against burglary at Brooklyn Heights, New 

 Jersey. Though this was the first practical telephone exchange, the idea of an 

 exchange system had been put forward by Dumont of Paris in 1851. This story 

 also is one of the greatest interest. 



The following chapters describe another epoch in telephone development : 

 the discovery of the microphone by Hughes, a musician by training, who " though 

 of Welsh parentage, was born in London and spent the greatest part of his life in 

 America, acting first as a professor of music and later occupying the chair of 

 Natural Philosophy in the College of Bairdstown, Kentucky.'' The merit of 

 Hughes's discovery, as stated by Lord Kelvin, mainly consists in this : " That 

 variation in electrical resistance by pressure is a property of the contact of two 

 conductors and that it is not confined to any one but to all conductors." Edison 

 had discovered two years before " that carbon of various forms when moulded 

 into buttons decreased the resistance of the passage of the electrical current by 

 pressure." There was great controversy as to the priority of invention of the 

 transmitter between Hughes and Edison, and the controversy ended in the law 

 courts. The work of other discoverers is clearly described in the chapter on the 

 microphone. 



The work of Reis is given in another chapter ; one interesting sentence 

 deserves quotation: "Scientists learned with expressed surprise many years later" 

 {i.e. after the account of Reis's inventions) " and after the electrical transmission 

 of speech had been effected by other means, that variations in contact pressure 

 would serve to transmit articular speech." Professional scientists are apt some- 

 times to regard themselves as the chief medium of scientific advance. This is a 

 just conclusion in many cases ; but it requires the natural genius of a discoverer 

 or inventor to make great strides, and as often as not the natural genius arises 

 outside the pale of the professional scientists. Summing up the results of Reis's 

 discoveries, Mr. Kingsbury says : 



" Whether the Reis instrument ever conveyed from talker to listener a sound 

 which could accurately be called speech can never with certainty be known. The 

 probabilities against it are so great that overwhelming evidence is necessary to 

 support the contention that speech was transmitted, and the contemporary evidence 

 does not indicate more than that sounds suggestive of words were sent." 



The remainder of the book will be of greater interest to the telephone engineer 

 than to the man of science, though there is much in it that will interest every one. 



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