of Ether Waves in Air. 779 



£ rays ; and though the ft rays, being most penetrating, 

 seem to have been most studied, the a particles may be really 

 more important. The /3 rays will tend to be magnetically 

 deflected towards the poles, presumably returning along 

 upper strata; the a particles will travel with the beam of 

 light and will be stopped in the upper regions of the atmo- 

 sphere, where they will tend to accumulate. If any y rays 

 exist in solar radiation, — and if /3 rays escape from the solar 

 atmosphere surely y rays will — they will exert a deep-seated 

 effect on our atmosphere; and a horizontal beam of them 

 might produce a fairly vertical stratum of ionized air, such 

 as would constitute a fairly effective screen or obstacle to 

 waves which are dependent on reflexion from an upper region 

 for their advance. 



Living under a reflecting dome it is natural that there 

 should be occasional local concentration of signals, and that 

 the varying shape and quality of the dome should greatly 

 influence the signals locally received. Earth or sea con- 

 ductivity has its more uniform effect, and assuredly conveys 

 some part of the signals ; but sea-water conduction is not 

 likely to be the cause of capriciousness in signalling, nor 

 would it contribute to daylight effects, nor to those speci- 

 fically observed at sunrise and sunset. All those must be due 

 to atmosphere. 



As regards practical telegraphy — on which here I am only 

 touching very incidentally — it by no means follows that 

 earth conduction and earth tapping ought not to be more 

 employed for signalling purposes than they are ; perhaps 

 already they are giving more assistance to long-distance 

 signalling than is recognized. It is quite possible that, by 

 the aid of electric vibrations maintained in the earth's crust, 

 aerial or Hertzian waves may ultimately be dispensed with, 

 and something less liable to stray or varying atmospheric 

 influences be employed. The trouble of distortion, to which 

 this method would be liable, could be overcome by emitting 

 only a single pure wave. Meanwhile, and so long as 

 Hertzian waves are used, it is safe to say that if by 

 reason of inequalities at sunrise the best conducting layer 

 of the atmosphere becomes corrugated or bent, it is quite 

 likely to divert a good deal of radiant energy which at 

 sufficiently oblique incidence would be reflected : and it 

 would be most deadly to the shorter waves. Also, the 

 effect of a vertical conducting layer, or of corrugations 

 in a horizontal one, would be likely to be felt most 

 when they were moderately near a sending or a receiving 

 station, and would probably be less noticeable when the 

 abnormalities were diffused over the half-way region ; though 



