'To place the insect within an induction coil, so as to disturb any
magnetic or diamagnetic sensibility which it seems just possible that
they may possess.'

To treat an insect as you would a magnetic needle and to subject it to
the current from an induction coil in order to disturb its magnetism
or diamagnetism appeared to me, I must confess, a curious notion,
worthy of an imagination in the last ditch. I have but little
confidence in our physics, when they pretend to explain life;
nevertheless, my respect for the great man would have made me resort
to the induction-coils, if I had possessed the necessary apparatus.
But my village boasts no scientific resources: if I want an electric
spark, I am reduced to rubbing a sheet of paper on my knees. My
physics cupboard contains a magnet; and that is about all. When this
penury was realised, another method was suggested, simpler than the
first and more certain in its results, as Darwin himself considered:

'To make a very thin needle into a magnet; then breaking it into very
short pieces, which would still be magnetic, and fastening one of
these pieces with some cement on the thorax of the insects to be
experimented on. I believe 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It becomes a living compass which, withdrawn from the action of the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