Perhaps he understood the position. If he did, he did not show it, for
his manner changed not in the least.

Satisfied with their mutual explanation, Manoel and Benito promised to
keep him in sight without doing anything to awaken his suspicions.

During the following days the jangada passed on the right the mouths of
the rivers Camara, Aru, and Yuripari, whose waters instead of flowing
into the Amazon run off to the south to feed the Rio des Purus, and
return by it into the main river. At five o'clock on the evening of the
10th of August they put into the island of Cocos.

They there passed a _"seringal."_ This name is applied to a caoutchouc
plantation, the caoutchouc being extracted from the _"seringueira"_
tree, whose scientific name is _siphonia elastica._

It is said that, by negligence or bad management, the number of these
trees is decreasing in the basin of the Amazon, but the forests of
seringueira trees are still very considerable on the banks of the
Madeira, Purus, and other tributaries.

There were here some twenty Indians collecting and working the
caoutchouc, an operation which principally takes place during the months
of May, June, and July.

After having ascertained that the trees, well prepared by the river
floods which have bathed their stems to a height of about four feet, are
in good condition for the harvest, the Indians are set to work.

Incisions are made into the alburnum of the seringueiras; below the
wound small pots are attached, which twenty-four hours suffice to fill
with a milky sap. It can also be collected by means of a hollow bamboo,
and a receptacle placed on the ground at the foot of the tree.

The sap being obtained, the Indians, to prevent the separation of its
peculiar resins, fumigate it over a fire of the nuts of the assai palm.
By spreading out the sap on a wooden scoop, and shaking it in the
smoke, its coagulation is almost immediately obtained; it assumes a
grayish-yellow tinge and solidifies. The layers formed in succession are
detached from the scoop, exposed to the sun, hardened, and assume the
brownish color with which we are familiar. The manufacture is then
complete.

Benito, finding a capital opportunity, bought from the Indians all the
caoutchouc stored in their cabins, which, by the way, are mostly built
on piles. The price he gave them was sufficiently remunerative, and they
were highly satisfied.

Four days later, on the 14th of August, the jangada passe