] It
reappears among the Arikara Indians of the upper Missouri,[543] and the
South American tribes of the Gran Chaco.[544] The first wooden boat was
made of a tree trunk, hollowed out either by fire or axe. The wide
geographical distribution of the dug-out and its survival in isolated
regions of highly civilized lands point it out as one of those necessary
and obvious inventions that must have been made independently in
various parts of the world.

[Sidenote: Relation of the river to marine navigation.]

The quieter water of rivers and lakes offered the most favorable
conditions for the feeble beginnings of navigation, but the step from
inland to marine navigation was not always taken. The Egyptians, who had
well-constructed river and marine boats, resigned their maritime
commerce to Phoenicians and Greeks, probably, as has been shown, because
the silted channels and swamps of the outer Nile delta held them at
arm's length from the sea. Similarly the equatorial lakes of Central
Africa have proved fair schools of navigation, where the art has passed
the initial stages of development. The kingdom of Uganda on Victoria
Nyanza, at the time of Stanley's visit, could muster a war fleet of 325
boats, a hundred of them measuring from fifty to seventy feet in length;
the largest were manned by a crew of sixty-four paddlers and could carry
as many more fighting men.[545] The long plateau course of the mighty
Congo has bred a race of river navigators, issuing from their riparian
villages to attack the traveler in big flotillas of canoes ranging from
fifty to eighty-five feet in length, the largest of them driven through
the water by eighty paddlers and steered by eight more paddles in the
stern.[546] But the Congo and lake boats are barred from the coast by a
series of cataracts, which mark the passage of the drainage streams down
the escarpment of the plateau.

[Sidenote: Retarded navigation.]

There are peoples without boats or rafts of any description. Among this
class are the Central Australians, Bushmen, navigation. Hottentots and
Kaffirs of arid South Africa,[547] and with few exceptions also the
Damaras. Even the coast members of these tribes only wade out into the
shallow water on the beach to spear fish. The traveler moving northward
from Cape Town through South Africa, across its few scant rivers, goes
all the way to Ngami Lake before he sees anything resembling a canoe,
and then only a rude dugout. Still greater is