ELECTRICITY DURING THE NINETEENTH CENTURY. 357 



effects, unless we class with such effects those of transmission without 

 wires. 



Wireless telegraphy of to-day is, however, a direct outcome of 

 Hertz's experiments on electric waves. It is but little more than ten 

 years since Hertz announced his results to the world. His work, sup- 

 plemented by that of Branly, Lodge, and more recently Marconi, has 

 made wireless telegraphy a possibility, and there are indications that 

 enormous distances may yet be covered by this ethereal transmission. 

 Just here we may refer to the fact— for it is a fact— that the electrical 

 energy transmitted over a line, which may be many miles in length, 

 really does not travel by the wire connecting the two points. It trav- 

 els in the ether surrounding the wire. The wire itself is, in fact, the 

 guiding core of the disturbances in the ether which proceed outward 

 in all directions to unlimited distances. The guiding core or conduct- 

 ing wire is needed to focalize or direct the delivery of the energy. 

 This curious conclusion of science, then, that the power from the 

 power-station wire travels in the space around the wires led from the 

 station is one of the results of recent electrical studies, just as with 

 light those studies begun by Maxwell and Hertz have led to the inev- 

 itable conclusion that the light of the candle, the light of a kerosene 

 lamp, and the light of a gas burner are all in essence electrical phe- 

 nomena, as are all forms of radiation in the ether. 



The wireless telegraph of to-day utilizes a sudden electrical disturb- 

 ance made at one point, which travels b}" the surroundmg ether in all 

 directions and is picked up in feeble fashion, it ma}" well be, by very 

 sensitive receiving instruments. The shock or disturbance to the 

 ether is thus recognized, and by a preconcerted system of signals the 

 slight disturbances are sent out in a sequence such as to convey intel- 

 ligible messages. Distances of upward of 100 miles are thus covered 

 with what must be regarded as an extremely feeble means so far as 

 the scale of the apparatus is concerned, and there would seem to be 

 no reason why the scale of operations greatl}' increased may not in the 

 near future widely extend the range over which wireless telegraphy 

 can work. 



The wonderful X ray and the rich scientitic harvest which has fol- 

 lowed the discovery by Rontgen of invisible radiation from a vacuum 

 tu])e were preceded by much investigation of the effects of electric 

 discharges in vacuum tubes, and T'ittor^', followed by Crookes, had 

 given special study to these effects in vCry high oi nearly perfect 

 vacua. Crookes, though specially enriching science hj his work, 

 missed the pecular X ray, which nevertheless must have been emitted 

 from his vacuum tubes, not only in his hands, but in those of subse- 

 quent students. It was as late as 1896 that Rontgen aiuiounced his 

 discovery. Since that time several other sources of invisible radiation 

 have been discovered, more or less similar in effect to the radiations 



