reach 450,000,000,000,000 the lowest visible light
rays manifest. Then come the orange rays, the golden yellow, the pure
yellow, the greenish yellow, the pure green, the greenish blue, the
ocean blue, the cyanic blue, the indigo, and finally the violet, the
highest degree of light which the human eye can register, and which
occurs when the vibrations reach the rate of 750,000,000,000 per second.
Then come the ultra-violet rays, invisible to human sight but registered
by chemical media. In this ultra-violet region lie the X-Rays, and the
other recently discovered high degree rays; also the actinic rays which,
while invisible to the eye, register on the photographic plate, sunburn
one's face, blister one's nose, and even cause violent explosions in
chemical substances exposed to them, as well as act upon the green
leaves of plants, causing the chemical transformation of carbonic acid
and water into sugar and starches. These forms of 'dark light,' that
is, light too high in degree to be perceived by the human eye, are but
faint indications of the existence of still higher and still finer
vibrations of substance and energy."

The Human Wireless Telegraph Instrument.

Having seen that the first question of the sceptical critics is capable
of being answered in the scientific spirit, and by ideas based upon
scientific investigation, we now turn to the second question of the same
critics, viz.: "Granted the existence of such vibratory energy, or
thought-waves, how and by means of what channel does the second person
receive these from the first person? How are they registered or
recorded?" This same question is also implied in the concluding sentence
of one of the scientists above quoted, viz.: "There is no good reason
whatever for supposing that matter is incapable of such intermediate
activity, or that such activity may not give rise to intermediate
sensations, provided that there are organs for taking up and sensifying
these movements." Let us see what science has to tell us regarding the
provision of Nature for the reception and "sensing" of this class of
vibratory energy. And the easiest way to ascertain the report of science
regarding this important matter is to consider carefully what
representative leading scientists have said concerning the same in their
writings or public addresses. We call your attention to the following
quotations from such sources.

A Great Scientist's Theory.

Let us begin with that great m