DEVELOPMENT OF TELEPHONE SERVICE 435 



secure a circuit from Philadelphia, but was unsuccessful for the same 

 reason. 



On July 11, 1876, Graham Bell varied the shape of the iron arma- 

 ture by attaching to the membrane a thin disk of Tagger's iron, almost 

 as large as the membrane. The next day he gave one of these tele- 

 phones to Sir William Thomson. It is said that during the trip home 

 the armature became bent, and useless in that condition. Neverthe- 

 less, Sir William used it to illustrate to the members of the British 

 Association for the Advancement of Science how Graham Bell's tele- 

 phone was the most marvelous of all the wonderful exhibits he had 

 seen in America. 



Graham Bell continued his experiments in improving the telephone, 

 and finding that the large iron disk was far superior to the small arma- 

 tures previously used, he concluded to dispense with the membrane 

 altogether. This he did in October, 1876. On fastening a thin disk 

 of steel in front of the electromagnet, conversation was carried on 

 more easily than ever before. Beferring to this improvement, Mr. 

 Storrow said: 



Perhaps the most important contribution which Mr. Bell made towards 

 improving speaking telephony, after the great conception and original instru- 

 ment of his first patent, consisted in the wonderful sensitiveness and quickness 

 of operation which he introduced into the instrument of the second patent, in 

 consequence of the conviction which he reached by study, thought and experi- 

 ment, that by so proportioning and combining all his parts as to sacrifice 

 absolute strength to absolute quickness, he could obtain the best results; and 

 then his innumerable experiments led him to the surprising discovery that a 

 piece of sheet iron was much quicker and more faithful in following the delicate 

 changes required for speech than the most delicate membrane is. 



Nine years later the commissioner of patents, under date of March 

 3, 1885, wrote: 



Bell's patent was issued on the 17th of March, 1876. At the Centennial 

 Exposition, held at Philadelphia that year (1876), he exhibited his telephone, 

 and it was adjudged by such eminent scientists as Professor Henry, Sir William 

 Thomson, of England, and Professor Gray, one of the contestants herein, to be 

 a success, and the world recognized Bell as the first inventor of a speaking 

 telephone. The indications are that it was not until the promised reward for 

 so important a public service became visible that his claim of priority was 

 called in question by any of the parties to this interference. 



That all the efforts of ihe several contestants who had attempted to pro- 

 duce a speaking telephone were failures seems clear from the record: that Bell 

 was the first to give to the world the art of transmitting articulate speech, and 

 the apparatus by which it could be successfully practised, was substantially 

 conceded tor a long period after his success in that behalf was placed beyond 

 doubt. Whether or not these several contestants had the instrumentalities 

 and appliances at that time from which success might have been realized if 

 those instrumentalities had been better understood is of little consequence. The 

 history of their experiments is a history of recorded failures. 



III. Devising the Telephone Exchange System 



Thirty years ago this summer the annual meeting of the British 

 Association for the Advancement of Science was held in Glasgow, 



