which changes the smell, I think that we are no longer at liberty to
quote scent as the guide of the Ants that return to the nest by the
road which they took at starting. Further tests will tell us more
about it.

Without interfering with the soil, I now lay across the track some
large sheets of paper, newspapers, keeping them in position with a few
small stones. In front of this carpet, which completely alters the
appearance of the road, without removing any sort of scent that it may
possess, the Ants hesitate even longer than before any of my other
snares, including the torrent. They are compelled to make manifold
attempts, reconnaissances to right and left, forward movements and
repeated retreats, before venturing altogether into the unknown zone.
The paper straits are crossed at last and the march resumed as usual.

Another ambush awaits the Amazons some distance farther on. I have
divided the track by a thin layer of yellow sand, the ground itself
being grey. This change of colour alone is enough for a moment to
disconcert the Ants, who again hesitate in the same way, though not
for so long, as they did before the paper. Eventually, this obstacle
is overcome like the others.

As neither the stretch of sand nor the stretch of paper got rid of any
scented effluvia with which the trail may have been impregnated, it is
patent that, as the Ants hesitated and stopped in the same way as
before, they find their way not by sense of smell, but really and
truly by sense of sight; for, every time that I alter the appearance
of the track in any way whatever--whether by my destructive broom, my
streaming water, my green mint, my paper carpet or my golden sand--the
returning column calls a halt, hesitates and attempts to account for