WIRELESS TELEGRAPHY 



along the line while going at full speed. This system 

 was installed on the Lehigh Valley Railroad in 1887. 

 Although the practical working of this telegraph was 

 entirely satisfactory, it was not found to pay commer- 

 cially, as there was not sufficient demand for such a 

 system, and it was shortly abandoned. 



In 1892, Sir William Preece and Mr. A. W. Heaviside, 

 experimenting with parallel telegraph lines situated 

 some ten miles apart, found that they could send and 

 receive messages readily at that distance. Their sys- 

 tem was given a practical test shortly after, communica- 

 tion by this means being attempted between the coast of 

 Wales at Cardiff and two small islands situated about 

 three and five miles respectively from the shore. On 

 Flat Holm, the nearer of the two islands, messages were 

 sent and received successfully from the mainland; but 

 on Steep Holm, two miles farther out, the signals could 

 be detected, but not distinguished with sufficient clear- 

 ness to be read. 



A little later than this Mr. Willoughby S. Smith and 

 Mr. W. P. Granville installed a system of communication 

 with Fastnet Rock, some seven miles off the coast of 

 Ireland, which, although not remarkable for the distance 

 to which the messages were sent, was very important 

 commercially. Cable communication with this rock, 

 on which is located an important lighthouse, was con- 

 stantly interfered with by the breaking and wearing out 

 of the cable, due to the violence of the waves in that 

 vicinity as well as the nature of the ocean bed. To over- 

 come this, Smith and Granville cut the cable at some 

 distance from shore and grounded the end of it with a 



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