72 POPULAR SCIENCE MONTHLY. 



telephone relay has been invented which preserves the form of the 

 first utterance, the vowel a loses its delicate characteristics, and 

 becomes simply a meaningless noise. It is maintained by some 

 authorities that such a relay can not be invented, that it is impos- 

 sible to preserve the delicate inflections of the human voice in 

 passing from one circuit to another, even through an infinitesimal 

 air gap or ether space. It is well, however, to reflect upon Hosea 

 Bigelow's sapient advice " not to prophesy unless you know." It 

 was maintained in the early days of the telephone that speech 

 would lose so many characteristics in the process of transmission 

 over wires and through magnetic apparatus that it would not be 

 intelligible. It is certain that at present long-distance transmis- 

 sion of speech can only be accomplished by using more powerful 

 transmitters, and by making the line of copper better fitted for 

 the transmission — just as quick transportation from place to place 

 has not been accomplished by quitting the earth and by flying 

 through space, but by obtaining more powerful engines and by 

 improving the roadbeds. 



The hopes of obtaining a relay for wireless telegraphy seem 

 as small as they do in telephony. The present method is prac- 

 tically limited to distances of fifty or sixty miles — distances not 

 much exceeding those which can be reached by a search-light in 

 fair weather. Indeed, there is a close parallelism between the 

 search-light and the spark used in Marconi's experiments: both send 

 out waves which differ only in length. The waves of the search- 

 light are about one forty-thousandth of an inch long, while the 

 magnetic waves of the spark, invisible to the eye, are three to four 

 feet — more than a million times longer than the light waves. These 

 very long waves have this advantage over the short light waves; 

 they are able to penetrate fog, and even sand hills and masonry. 

 One can send messages into a building from a point outside. A 

 prisoner could communicate with the outer world, a beleaguered 

 garrison could send for help, a disabled light-ship could summon 

 assistance, and possibly one steamer could inform another in a fog 

 of its course. 



Wireless telegraphy is the nearest approach to telepathy that 

 has been vouchsafed to our intelligence, and it serves to stimulate 

 our imagination and to make us think that things greatly hoped 

 for can be always reached, although not exactly in the way ex- 

 pected. The nerves of the whole Avorld are, so to speak, being 

 bound together, so that a touch in one (N)untrv is transmitted in- 

 stantly to a far-distant one. Why should we not in time speak 

 through the earth to the antipodes? If the magnetic waves can 

 pass through brick and stone walls and sand hills, why should we 



