although the wind still blew from
the north.

Now on this first occasion all the butterflies hastening to the prisoner
entered the garden from the north. They followed the direction of the
wind; not one flew against it. If their guide was a sense of smell like
ours, if they were guided by fragrant atoms suspended in the air, they
should have arrived in the opposite direction. Coming from the south, we
might believe them to be warned by effluvia carried on the wind; coming
from the north in time of _mistral_, that resistless sweeper of earth
and air, how can we suppose that they had perceived, at a remote
distance, what we will call an odour? The idea of a flow of odoriferous
atoms in a direction contrary to that of the aerial torrent seems to me
inadmissible.

For two hours, under a radiant sun, the visitors came and went before
the outer wall of the study. Most of them sought for a long time,
exploring the wall, flying on a level with the ground. To see them thus
hesitating you would say that they were puzzled to find the exact
position of the lure which called them. Although they had come from such
a distance without a mistake, they seemed imperfectly informed once they
were on the spot. Nevertheless, sooner or later they entered the room
and saluted the captive, without showing any great ardour. At two
o'clock all was over. Ten butterflies had arrived.

During the whole week, and always about noon, at the hour of the
brightest sunlight, the butterflies arrived, but in decreasing numbers.
The total approached forty. I thought it useless to repeat experiments
which would add nothing to what I had already learned. I will confine
myself to stating two facts. In the first place, the Lesser Peacock is
diurnal; that is to say, it celebrates its mating under the dazzling
brilliance of noon. It needs the full force of the sunlight. The Great
Peacock, on the contrary, which it so closely resembles both in its
adult form and the work of its caterpillar, requires the darkness of the
first hours of the night. Who can explain this strange contrast in
habits?

In the second place, a powerful current of air, sweeping away in a
contrary direction all particles that might inform the sense of smell,
does not prevent the butterflies from arriving from a direction opposite
to that taken by the effluvial stream, as we understand such matters.

To continue: I needed a diurnal moth or butterfly: not the Lesser
Peacock, which came too