the south it occurs in March. Consequently the right-hand tributaries
and the left-hand tributaries bring down their floods at half-yearly
intervals, and hence the level of the Amazon, after reaching its
maximum in June, gradually falls until October.

This Joam Garral knew by experience, and he intended to profit by the
phenomenon to launch the jangada, after having built it in comfort on
the river bank. In fact, between the mean and the higher level the
height of the Amazon could vary as much as forty feet, and between
the mean and the lower level as much as thirty feet. A difference of
seventy feet like this gave the fazender all he required.

The building was commenced without delay. Along the huge bank the
trunks were got into place according to their sizes and floating
power, which of course had to be taken into account, as among these
thick and heavy woods there were many whose specific gravity was but
little below that of water.

The first layer was entirely composed of trunks laid side by side. A
little interval had to be left between them, and they were bound
together by transverse beams, which assured the solidity of the
whole. _"Piaçaba"_ ropes strapped them together as firmly as any
chain cables could have done. This material, which consists of the
ramicles of a certain palm-tree growing very abundantly on the river
banks, is in universal use in the district. Piaçaba floats, resists
immersion, and is cheaply made--very good reasons for causing it to
be valuable, and making it even an article of commerce with the Old
World.

Above this double row of trunks and beams were disposed the joists