EFFECTS OF ELECTRICAL WAVES 493 



pass between the electrodes, as it does in my experiments, 

 but we have to do with a silent discharge. In this way, 

 however, the oscillatory character of the discharge practi- 

 cally disappears. As is well known, a tuning-fork emits a 

 sound only when the prongs, after they have been moved 

 from their state of rest, spring back quickly. When they 

 return to a state of rest very slowly, they do not give rise to 

 sound. It is the same in the case of a discharge. In the 

 case of a spark discharge we deal with an abrupt release of 

 the tension which must occur in an oscillatory way. In the 

 case of a silent discharge we do not deal with oscillations at 

 all. If Danilewsky speaks of an oscillatory discharge 

 under such circumstances, it is to be remembered that 

 in reality the oscillatory character of the discharge dis- 

 appears so completely in his experiments, that they cor- 

 roborate beautifully my view that these effects are not 

 determined through oscillations, but through a single elec- 

 trostatic discharge. 



Of course, it might yet be maintained that electric waves 

 are present in this case in so far as the interruptions by the 

 hammer of the Ruhmkorff are periodic. If we estimate these 

 interruptions in the Ruhmkorff coil as 60 per second (which 

 is certainly high), then, when the velocity of light is in 

 round figures 300,000 km., the wave-length is over 5,000 

 km.! Does Danilewsky expect us to believe that these 

 waves can interfere between his electrodes which are sepa- 

 rated from 50 to 100 cm. ? It is also entirely wrong to apply 

 to such waves the term "rays." We expect rays to move in 

 a straight line, and for this reason we do not speak of sound- 

 rays, since these can go around a corner. The "rays" of 

 Danilewsky would not only go around a corner, but around 

 the Alps, or around the moon. In a similar way there is no 

 sense in saying, as Danilewsky does, that in these experi- 

 ments a "neutralisation des polarit^s e"lectriques" occurs. 



