elay.

A loud noise stifles a feeble note and prevents it from being heard; a
brilliant light eclipses a feeble glimmer. Heavy waves overcome and
obliterate ripples. In the two cases cited we have waves of the same
nature. But a clap of thunder does not diminish the feeblest jet of
light; the dazzling glory of the sun will not muffle the slightest
sound. Of different natures, light and sound do not mutually interact.

My experiment with spike-lavender, naphthaline, and other odours seems
to prove that odour proceeds from two sources. For emission substitute
undulation, and the problem of the Great Peacock moth is explained.
Without any material emanation a luminous point shakes the ether with
its vibrations and fills with light a sphere of indefinite magnitude.
So, or in some such manner, must the warning effluvium of the mother Oak
Eggar operate. The moth does not emit molecules; but something about it
vibrates, causing waves capable of propagation to distances incompatible
with an actual diffusion of matter.

From this point of view, smell would have two domains--that of particles
dissolved in the air and that of etheric waves.[7] The former domain
alone is known to us. It is also known to the insect. It is this that
warns the Saprinidae of the fetid arum, the Silphidae and the Necrophori
of the putrid mole.

The second category of odour, far superior in its action through space,
escapes us completely, because we lack the essential sensory equipment.
The Great Peacock moth and the Oak Eggar know it at the time of their
nuptial festivities. Many others must share it in differing degrees,
according to the exigencies of their way of life.

Like light, odour has its X-rays. Let science, instructed by the insect,
one day give us a radiograph sensitive to odours, and this artificial
nose will open a new world of marvels.

CHAPTER XVII

THE ELEPHANT-BEETLE

Some of our machines have extraordinary-looking mechanisms, which remain
inexplicable so long as they are seen in repose. But wait until the
whole is in motion; then the uncouth-looking contrivance, with its
cog-wheels interacting and its connecting-rods oscillating, will reveal
the ingenious combination in which all things are skilfully disposed to
produce the desired effects. It is the same with certain insects; with
certain weevils, for instance, and notably with the Acorn-beetles or
Balanini, which are adapted, as their name denotes, to the exploitati