Thus in the
phenomena of emission, ponderable matter is seen to give birth to
waves which are transmitted by the ether, and by the phenomena of
absorption it is proved that these waves disappear and excite
modifications in the interior of the material bodies which receive
them. We here catch in operation actual reciprocal actions and
reactions between the ether and matter. If we could thoroughly
comprehend these actions, we should no doubt be in a position to fill
up the gap which separates the two regions separately conquered by
physical science.
In recent years numerous researches have supplied valuable materials
which ought to be utilized by those endeavouring to construct a theory
of radiation. We are, perhaps, still ill informed as to the phenomena
of luminescence in which undulations are produced in a complex manner,
as in the case of a stick of moist phosphorus which is luminescent in
the dark, or in that of a fluorescent screen. But we are very well
acquainted with emission or absorption by incandescence, where the
only transformation is that of calorific into radiating energy, or
_vice versa_.
Pages:
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381