at our foot-marks on the ground, not at the
marks of our hands!"

With these words, from a tracker's point of view, the local wit set the
entire company in shrieks of laughter at his quick repartee.

"Oh, yes!" said I; "but with the thumb-marks I may perhaps trace, not
only where you come from, but also where your great-grandfather, who is
now dead, came from."

That was too much for them. All had been anxious to make a smudge with
smoke-black upon my note-book. Now they all refused to do any more
thumb-marking, and walked away; but I had fortunately already finished
the work I needed from them.

The Bororos--in fact, most Indian tribes of Central Brazil--knew nothing
whatever of navigation. This was chiefly due to the fact that all the
woods of Central Brazil had so high a specific gravity that not one of
them would float. Hence the impossibility of making rafts, and the
greatly increased difficulty in making boats. As for making dug-outs, the
Indians had neither the patience nor the skill nor the tools to cut them
out of solid trees. Moreover, there was really no reason why the Indians
should take up navigation at all when they could do very well without it.
They could easily get across the smaller streams without boats, and they
were too timid to go and attack inimical tribes on the opposite banks of
unfordable rivers. Besides, the Indians were so few and the territory at
their entire disposal so great, that there was no temptation for them to
take up exploring, particularly by water.

They were all good swimmers. When the river was too deep to ford they
merely swam across; or else, if the river were too broad and swift, they
improvised a kind of temporary raft with fascines or bundles of dried
_burity_ leaves, to which they clung, and which they propelled with their
feet. These fascines were quite sufficient to keep them afloat for a
short time, enabling them also to convey a certain amount of goods across
the water.

In other countries, such as in Central Africa among the Shilucks and the
Nuers of the Sobat River (Sudan), and the natives on Lake Tchad, I have
seen a similar method adopted in a far more perfected fashion. The
Shilucks, for instance, cleverly built big boats of fascines--large
enough to carry a great number of warriors. Such was not the case with
the bundles of _burity_ of the Indians--which merely served for one or at
the most two people at a time, and then only until the bundle became
soaked