ETHER WAVES AND THE MESSAGES THEY BRING 



LESLIE BIRCHARDSEELY 



Delivered December 20, 1916 



HOWEVER interesting it might be to do so, it is not possible for us at this 

 time to trace historically the progress of knowledge which has made 

 possible the assumption impKed in the first word of our subject. That 

 ether exists has come to be commonly accepted as a fact. The transmission 

 through space of energy by wave motion would be impossible in the absence 

 of some all-pervading medium. The universal acceptance of the wave theory 

 of light thus carries with it the tacit recognition of the fact that luminiferous 

 ether exists. 



The ether- wave theory, applied first to light, the only form of this energy 

 which appeals directly to our senses, has been extended gradually until it now 

 includes a wide range of wave energy which may be detected only indirectly. 

 We cannot go either into the history of this development or into the proofs of 

 the existence of the ether waves themselves, except incidentally. We must 

 confine ourselves for the most part to a mere description of the waves and to 

 some of the more important facts which they have revealed, or, as our subject 

 has it, the messages they bring to us. It might be well to state, however, that 

 these various forms of ether energy have been ascribed to wave motion because 

 they exhibit interference, resonance, and other properties and phenomena 

 known to exist only in waves. 



Two of the things we must speak of most frequently in our description of 

 ether waves are wave lengths and frequencies. By a wave length we mean the 

 distance between any phase in one wave to the same phase in the next wave 

 following or preceding. Now the wave length of these waves is exceedingly 

 variable, being in some cases so minute that a special unit has been devised for 



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their measurement. This is called the Angstrom unit and is one ten-millionth 

 of a millimeter. That means that two hundred and fifty thousand of these 

 units make approximately a thousandth of an inch. Other waves are measured 

 in miles. By frequency we mean the number in a train of waves which passes 

 a given point in a unit of time, e. g., in a second. Of these waves, all lengths 

 seem to travel at the same speed ; thus the frequencies are inversely proportional 



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