DIFFERENT KINDS OF WILD RUBBER--_continued_
Beyond the Amazon Valley, the chief wild-rubber producing countries in
the New World are Central America and Mexico. Both are homelands of
the Castilloa, and Mexico has large areas of a rubber-giving shrub
called “Guayule.”
Now that you have seen how caucho is collected in South America, you
will, I feel sure, be all the more interested to get a peep at some
caucho-gatherers in Central America, who work in a different way. So
let us go to Nicaragua.
Once more we are standing in the maze of a tropical forest. Just in
front of us is a tree, which has big leaves hanging independently
of each other from either side of the branches. By the shape and
arrangement of its foliage we recognize it as a Castilloa. Under this
tree stands a semi-clad, brown figure. What a dwarf he looks! No
wonder; the tree with whose height you are unconsciously comparing his
stature is a giant, whose top-to-root measure is well over 100 feet.
The native is going to collect caucho-milk. He does not cut down the
tree, but taps it as it stands. With a big knife he makes V-shaped
cuts in the trunk, operating on the lower part from the ground, and
on the upper part from a hanging ladder. This rough-looking climbing
apparatus he has made for himself out of bush-rope. You can see for
yourself that it is easy enough for him to find bush-rope in this
forest; from the branches of numbers of the trees around hang lengths
of naturally-corded fibre, some of it stringlike, much of it thicker
than any rope that is ever made in a factory.
The caucho-milk runs out from the cuts and trickles down the trunk into
a calabash. When the collector has tapped several trees, he puts all
the milk into an old pan, and adds to it some watery juice which he
has obtained from a particular variety of creeper. He then stirs the
mixture, and in a little time the rubber coagulates into lumps, which
float on the surface. He takes these pieces of rubber out of the pan,
and kneads them into flat, round “biscuits.”
Our next visit is to Mexico. Here we will not go into the forests,
among the caucho-gatherers; for time is pressing, and rather than look
at similar sights to those with which we are already acquainted, we
choose to make for a part of this country where we can watch, amidst
quite new surroundings, a novel process of obtaining rubber from a
plant which is quite different from any we can see elsewhere.
We are on the stony soil of a Mexican plain, standing knee-deep in
scrub. As far as the eye can reach in every direction the ground is
covered with dwarfish vegetation, which consists of a shrub called
“guayule.”
Guayule covers acres upon acres of the Mexican plains. It contains
a large amount of rubber, which is secreted by all the plant-cells.
Unlike most rubber-giving vegetation, this shrub does not yield its
riches in the form of milk; the milk naturally coagulates within the
cells and forms tiny particles of rubber. Presently you will see how
these particles are routed out of their hiding-place.
In the district we have come to visit, several Mexicans are busy
gathering in a harvest of guayule. As you watch them at work, you
notice that they pull up some of the shrubs by the roots, but others
they pass by. No, the plants they leave in the ground are not by any
means poor specimens; they are young guayules, as yet under 18 inches
high, which are being left to grow and furnish another crop.
Presently we espy quite a number of donkeys coming leisurely along
towards us over the plain. They have been down to a packing-shed close
by with a load of guayule, and are now returning for another load. When
they reach the harvest-field, great bundles of the shrub are piled up
on their backs, until we can hardly see anything of the useful little
beasts but a row of heads and an array of paws. However, their burden
is not so heavy as its bulk would have us imagine. We follow the
caravan of donkeys to the packing-shed and see them unloaded. Then we
watch the guayule being pitched by hand into crates and tightly jammed
therein by being jumped on by the packers. When the bales are taken out
of the crates they remind us of trusses of hay. The bales are weighed,
stacked in carts, and taken to the factory.
Seated on a bale in one of these carts, we, too, go to the factory.
Here we see the crop of guayule being crushed between rollers, and
for the moment we are reminded of a sugar-mill. The crushed plant,
a mixture of bits of wood and atoms of rubber, is conducted to a
pebble-mill, which is a drum half filled with stones and water. The
mill is rotated, and the rubbing action which is thus set up rolls the
rubber into larger pieces and grinds the wood to pulp.
The mixture is now pumped into large tanks. The rubber, being lighter
than water, floats; the wood, being heavier, sinks. The rubber is
skimmed off and purified, after which it is washed and put into bags
ready to go to market.
Guayule rubber is of sufficiently good quality to be used for all but
the highest class rubber goods, such as surgical appliances.