WIRELESS TRANSMISSION OF ENERGY THOMSON. 



253 



no. 2 IB. 



•5 



As this action goes oiij however, the zone of charged surface 

 widens, and ether waves are, so to speak, detached from the antenna, 

 and electrostatic lines join now through the air or ether above the 

 successive zones which surround the antenna as great circles or flat 

 rings of the sea surface. A plus area is followed by a minus, a minus 

 by a plus, etc., and to indicate the effect in the space above, we draw 

 lines which follow these areas, extending up into the ether above the 

 surface, but moving away from the antenna with the velocity of light. 

 The moving charges in the sea surface represent radial currents 

 which are in opposite phase at different portions of the sea surface, 

 and spreading at 186,000 miles per second, and these currents neces- 

 sarily generate magnetism or lines of magnetic force in the medium 

 directly above them. These lines extend around in zones with dimin- 

 ishing intensity upward from the sea surface as the distance from the 

 surface increases. Even within the 

 water itself a similar action, but 

 more restricted, takes place. The 

 charges in the water are connected 

 by electrostatic stress lines, and the 

 compensating magnetic field fol- 

 lows the current, but this " under 

 water" effect does not concern us, 

 as what we work with is the energy 

 conveyed in the space above the 

 sea, the other not being so easily 

 recoverable. 



The system as thus far consti- 

 tuted is merely an arrangement for 

 delivering energy in high-frequency 

 waves to the widespread medium 



around the antenna. There is no selective action whereby it is 

 focused anywhere — it is as a " voice crying in the wilderness." It 

 can be picked up or recognized in any direction by anyone who is 

 within range. If, now, we are to receive signals such as are made 

 by interrupting or disturbing at intervals this system of radiation 

 of energy, as in ordinary telegraphy, we must set up somewhere a 

 receiving apparatus which will enable us to pick up whatever small 

 fraction of the energy reaches it and, if possible, a sufficient fraction 

 of such energy for the recognition of the signals. If the signal can 

 be recognized — no matter how small the fraction of the energy sent 

 out is which we collect at the receiving station — the system succeeds. 

 There is no question of efficient transmission, as there is in the ordi- 

 nary power-transmission systems. The latter are for the transmis- 

 sion of energy with as little loss as possible, the former for the trans- 

 mission of signals only. 



