WIRELESS TELEGRAPHY. 293 



less. This is possible already. Doubtless a \ ast deal more will be 

 done in a year or two or less, and meanwhile the authorities should be 

 making all necessary arrangements for the universal application of 

 wireless telegraphy in the navy." 



The most important results, from a technical point of view, obtained 

 during- the maneuvers were the proof of the great increase of distance 

 obtained by employing the transformer in the receiver, as already 

 explained, and also that the curvature of the earth which intervened, 

 however great the distance attained, was apparently no obstacle to the 

 transmission. The maximum height of the top of the wire attached 

 to the instruments above the water did not on any occasion exceed 170 

 feet, but it would have been geometrically necessary to have had masts 

 700 feet high on each ship in order that a straight line between their 

 tops should clear the curved surface of the sea when the ships were 60 

 nautical miles apart. This shows that the Hertzian waves had either 

 to go over or round the dome of water 530 feet higher than the tops of 

 the masts, or to pass through it, which latter course I believe would 

 be impossible. 



Some time after the naval maneuvers, with a view to showing the 

 feasibility of communicating over considerable distances on land, it was 

 decided to erect two stations, one at Chelmsford and another at Har- 

 wich, the distance between them being 40 miles. These installations 

 have been working regularly since last September, and my experi- 

 ments and improvements are continually being carried out at Chelms- 

 ford, Harwich, Alum Bay, and North Haven, Poole. 



In the month of September last, during the meetings of the British 

 Association in Dover and of the Association Francaise pour Tavance- 

 ment de Science in Boulogne, a temporary installation was fixed in the 

 Dover town hall, in order that members present should see the practi- 

 cal working of the system between England and France. Messages were 

 exchanged with ease between Wimereux, near Boulogne, and Dover 

 town hall. In this way it was possible for the members of the two asso- 

 ciations to converse across the channel, over a distance of 30 miles. 



During Professor Fleming's lecture on the Centenaiy of the Electric 

 Current, messages were transmitted direct to and received from France, 

 and via the South Foreland light-house to the East Goodwin light- 

 ship. An interesting point was that it was demonstrated that the 

 great masses of the Castle Rock and South Foreland cliffs lying 

 between the town hall, Dover, and the light-house did not in the 

 least degree interfere with the transmission of signals. The result 

 was, however, by no means new. It only continued the results of 

 many previous experiments, all of them showing that rock masses of 

 very considerable size intervening between two stations do not in the 

 least affect the freedom of communication by ether wave telegraphy. 8 



a See Journal of the Institution of Electrical Engineers, April, 1899, p. 280. 



