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On the Transmission of Electric Waves. [May 1. 



on the transmitter I have never known a signal to be received on 

 board another ship over 2 miles distant. 



My experience demonstrates most clearly, and with no marked 

 exception, that, for signalling any distance beyond a few miles, the 

 combination of aerial wires and good earths is essential, for both 

 transmitting and receiving instruments. 



Summary. 



The results of my observations may be briefly summed up as 

 follows : — 



(1) That intervening land of any kind reduces the practical signal- 

 ling distance between two ships or stations, compared with the 

 distance obtainable in the open sea, and that this loss in distance 

 varies with the height, thickness, contour, and nature of the land ; 

 and that, based on the results of these observations, it may be con- 

 cluded that some of the waves of electric induction, transmitted by 

 wireless telegraphy, may pass through, over, and possibly round the 

 land, and are comparable to the passage of ocean waves through or 

 over a reef, or round high land, which waves proceed along their 

 course with diminished energy, after passing such obstructions. 



(2) That material particles, such as dust and salt held in suspension 

 in a moist atmosphere, also reduce the signalling distance, probably 

 dissipating and absorbing the waves. 



(3) That electrical disturbance in the atmosphere also acts most 

 adversely to the regular transmission of these waves, in addition to 

 affecting the receiving instruments by lightning discharges. 



(4) That a system of transmission in which the oscillations are 

 rapidly damped is irregular in its action on distant receivers, owing 

 to the irregularity of the train of waves giving rise to different types 

 of disturbance at different parts of their path, which may not have at 

 certain points the necessary cumulative effect on the receiving circuit. 



(5) That the earth's function in the transmission of waves is most 

 important ; but that its importance is secondary to that of the aerial 

 wire, or capacity insulated in the air above the surface of the sur- 

 rounding sea or earth. 



I have to thank many of my brother officers and men in H.M.'s. 

 Navy for the valuable assistance they have ungrudgingly given me in 

 carrying out my experiments. 



