Leaving on one side the manifold but purely electrical consequences of
this and the numerous researches relating to the production or to the
properties of the waves--some of which, those of MM. Sarrazin and de
la Rive, Righi, Turpain, Lebedeff, Decombe, Barbillon, Drude, Gutton,
Lamotte, Lecher, etc., are, however, of the highest order--I shall
only mention here the studies more particularly directed to the
establishment of the identity of the electromagnetic and the luminous
waves.
The only differences which subsist are necessarily those due to the
considerable discrepancy which exists between the durations of the
periods of these two categories of waves. The length of wave
corresponding to the first spark-gap of Hertz was about 6 metres, and
the longest waves perceptible by the retina are 7/10 of a micron.[24]
[Footnote 24: See footnote 3.]
These radiations are so far apart that it is not astonishing that
their properties have not a perfect similitude. Thus phenomena like
those of diffraction, which are negligible in the ordinary conditions
under which light is observed, may here assume a preponderating
importance.
Pages:
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256