ve that such a little magnet, from its close proximity to
the nervous system of the insect, would affect it more than would the
terrestrial currents.'

There is still the same idea of turning the insect into a sort of bar
magnet. The terrestrial currents guide it when returning to the nest. It
becomes a living compass which, withdrawn from the action of the earth
by the proximity of a loadstone, loses its sense of direction. With a
tiny magnet fastened on its thorax, parallel with the nervous system
and more powerful than the terrestrial magnetism by reason of its
comparative nearness, the insect will lose its bearings. Naturally, in
setting down these lines, I take shelter behind the mighty reputation
of the learned begetter of the idea. It would not be accepted as serious
coming from a humble person like myself. Obscurity cannot afford these
audacious theories.

The experiment seems easy; it is not beyond the means at my disposal.
Let us attempt it. I magnetise a very fine needle by rubbing it with my
bar magnet; I retain only the slenderest part, the point, some five or
six millimetres long. (.2 to.23 inch.--Translator's Note.) This broken
piece is a perfect magnet: it attracts and repels another magnetised
needle hanging from a thread. I am a little puzzled as to the best way
to fasten it on the insect's thorax. My assistant of the moment,
the pharmaceutical student, requisitions all the adhesives in his
laboratory. The best is a sort of cerecloth which he prepares specially
with a very fine material. It possesses the advantage that it can be
softened at the bowl of one's pipe when the time comes to operate out of
doors.

I cut out of this cerecloth a small square the size of the Bee's thorax;
and I insert the magnetised point through a few threads of the material.
All that we now have to do is to soften the gum a little and then dab
the thing at once on the Mason-bee's back, so that the broken needle
runs parallel with the spine. Other engines of the same kind are
prepared and due note taken of their poles, so as to enable me to point
the south pole at the insect's head in some cases and at the opposite
end in others.

My assistant and I begin by rehearsing the performance; we must have a
little practice before trying the experiment away from home. Besides, I
want to see how the insect will behave in its magnetic harness. I take a
Mason-bee at work in her cell, which I mark. I carry her to my study,
at the oth