136 The Smithsonian Institution 



Sir Charles Wheatstone, who, with his associate, Sir Wil- 

 liam Fothergill Cooke, developed the system of Schilling after 

 it left the hands of Gauss and Weber, was the first to bring 

 the telegraph into practical commercial use ; and although 

 his plan, involving as it did the employment of a number of 

 separate line wires and needle-indicators, was soon abandoned 

 on account of its expense and perplexity, it is still the popular 

 belief in England that Wheatstone was the inventor of the 

 electric telegraph. The reason for this is, in part, that he was 

 the first in England to secure patents for the telegraph; and, 

 in part also, that he at one time claimed to have been the 

 discoverer of the intensity magnet. There is, nevertheless, 

 good reason to believe that Wheatstone was directly indebted 

 to Henry for the information which enabled him to utilize the 

 intensity magnet in connection with his telegraph. He was 

 engaged in his experiments when visited by Henry and 

 Bache at King's College, in April, 1837, and his apparatus 

 was examined and his plans discussed by them. He had al- 

 ready found the electro-magnet inefficient as a sound-signal, 

 and was endeavoring to introduce a secondary circuit as a 

 remedy for the diminution of force encountered in the long 

 circuit. Henry has recorded that he then explained to 

 Wheatstone a different method of bringing the second gal- 

 vanic circuit into action, and it was Henry's method which 

 Wheatstone employed in his final successes. 1 



"It is evident," writes Mr. Fahie, an English expert, "that 

 it was not until after the interview with Henry that Wheat- 

 stone recognized the applicability of Ohm's law to tele- 

 graphic circuits." 2 Mr. Fahie, however, ignores the fact that 

 it was Henry's discovery, and not Ohm's formula, which was 



1 Cooke records that on many occasions in 2 Fahie, J. J., " A History of Electric Tele- 

 March and April the efforts of Wheatstone graphy to the Year 1837," London, 1884, 

 and himself to excite magnetism at long dis- page 515. 

 tances were unsuccessful. 



