TROPICAL PLANTS USED FOR INDUSTRIAL PURPOSES.
Cotton--Its Cultivation in the United States--Caoutchouc and Gutta
Percha--Manner in which these resins are collected--Indigo--The
British Logwood cutters in Honduras--Brazil Wood--Arnatto.
Under the Plantagenets and the Tudors, wool formed the chief export of
England. The pastoral races that inhabited the British Isles, unskilled
in weaving, suffered the more industrious Flemings to convert their
fleeces into tissues; and the dominions of the Duke of Burgundy,
enriched by manufactures and by the stimulus they gave to agriculture,
became the most prosperous part of Europe. At length the islanders
began to discover the sources of the wealth which rendered Ghent and
Bruges, Ypres and Louvain, the marvel and envy of the mediæval world;
and gradually learning to keep their wool at home, invited the Flemings
to the shores of England.
The bigoted oppression of Spain came in aid of this more enlightened
policy: our wool ceased to be sent abroad, and English cloth eventually
became the chief of our exports. But, like all human affairs, trade
is subject to eternal fluctuation, new wants are constantly created,
new markets opened, new articles introduced, and thus, almost within
the memory of living man, the wool-manufactory has ceased to be the
great staple of our industry; and, thanks to the inventive genius of
our Arkwrights and Cromptons, a vegetable fibre furnished by a plant
totally unknown to our forefathers, now ranks as the first of all the
world-wide importations of England.
There are many different species of the cotton-plant, herbaceous,
shrubby, and arboreal. Their original birthplace is the tropical zone,
where they are found growing wild in all parts of the world; but the
herbaceous species still thrive under a mean temperature of from 60° to
64° F., and are capable of being cultivated with advantage as far as
40° or even 46° N. lat. The five-lobed leaves have a dark green colour,
the flowers are yellow with a purple centre, and produce a pod about
the size of a walnut, which, when ripe, bursts and exhibits to view the
fleecy cotton in which the seeds are securely embedded.
It is almost superfluous to mention that the United States is the first
cotton-producing country in the world. The area suitable for cotton
south of the thirty-sixth degree of latitude, comprises more than
39,000,000 acres, of which less than one-sixth part is now devoted to
the plant. The yield depends in part upon the length of the season.
Seven months are required for an average crop, and the average periods
in which the last killing frost of spring and the first killing frost
of autumn occur are March 23, and October 26. Cotton is cultivated
in large fields, and when the soil is superior, the plant rises to a
height of six or eight feet, although in the richest cane-brake soil,
exhausted by successive crops, it dwindles down to a height of three
or four feet only. The aspect of a cotton field is most pleasing in
the autumn, when the dark-coloured foliage and bright yellow flowers,
intermingling with the snow-white down of the pods when burst, produce
a charming contrast. At that time all hands are at work, for it is
important to pluck as much as possible during the first hours of
morning, since the heat of the sun injures the colour of the cotton,
and the over-ripe capsules shed their contents upon the ground, or
allow the wind to carry them away.
The collected produce is immediately carried to the steam-mill to
be cleansed of the seeds, and then closely packed in bales, which
in the seaports are further reduced by hydraulic presses to half of
their previous volume, thus causing a great saving in the freight.
Large clippers frequently carry eight or ten thousand of these bales
to Liverpool, whence, perhaps on the day of their arrival, they are
conveyed by rail to the next manufacturing town, which returns them in
a few days to the port, ready to clothe the Australian gold-digger or
the labourer on the banks of the Ganges.
India, which still in the last century provided Europe with the finest
cambrics and muslins, now yearly receives from England cotton goods to
a large amount. Thus the stream of trade may be said to have rolled
backwards to its source, for though the wants of the Hindoo are easily
satisfied, and cotton grows at his very door, yet his hand-loom is
unable to compete with the machinery and the capital of England.
Even in the exportation of the raw material he labours under great
disadvantage when compared with America, though railroads and a better
system of culture have done much to improve the quality and facilitate
the transport of Indian cotton.
When we consider the luxuriance of vegetation in the tropical zone, it
is not to be wondered at that so many plants of those climes abound
with juices of a variety and richness unknown to those of the temperate
latitudes. The resins and gums which our indigenous trees produce,
either in smaller quantities or fit only for common uses, are there
endowed with higher virtues, and ennobled, as it were, by the rays of
a more powerful sun. Sometimes they exude spontaneously through the
rind and harden in the atmosphere; more frequently a slight incision is
required to make the sap gush forth in which they are dissolved, but
in every case they require but trifling labour for their collection.
Many of them have medicinal qualities, others are esteemed for their
aromatic odour, but none ranks higher in a commercial and technical
point of view than caoutchouc or India-rubber, which was first brought
from South America to Europe as a great curiosity at the beginning of
the last century, and is now absolutely indispensable for a thousand
different uses. Nothing was known even of its origin until the year
1736, when the French naturalist La Condamine, while exploring the
banks of the Amazon, discovered that it was chiefly produced by the
Siphonia elastica, a large tree growing wild in the primitive forests
along the borders of the rivers in Guiana and North Brazil.
The resin is collected by the Indians in a very simple manner. With a
small hatchet they make deep and long incisions in the rind, from which
a milky sap abundantly exudes. A small wooden peg is then fixed into
each aperture to prevent its closing, and a cup of moist clay fastened
underneath, which in about four or five hours is filled with as many
table-spoonfuls of the juice. The produce of a number of incisions
having been gathered in a large earthen vessel, is then spread in thin
coatings upon moulds made of clay, and dried, layer after layer, over a
fire, until the whole has acquired a certain thickness. When perfectly
dry, the clay form within is broken into small fragments, and the
pieces are extracted through an aperture, which is always left for the
purpose.
Besides the Siphonia elastica, many other American trees, belonging to
the families of the Euphorbiaceæ and Urticeæ, afford excellent kinds of
caoutchouc; and since it is become so valuable an article of commerce,
the East Indies, and Java likewise, yield considerable quantities,
chiefly from the Urceola elastica and the Ficus elastica.
The Icosandra Gutta, which furnishes the gutta percha of commerce, is a
native of the Eastern Archipelago and the adjacent lands. A few years
since, this substance, now so celebrated and of such wide extended
use, was totally unknown in Europe, for though from time immemorial
the Malays employed it for making the handles of their hatchets
and creeses, it was only in the year 1843 that Mr. Montgomery, an
English surgeon, having casually become acquainted with its valuable
properties, sent an account of it, with samples, to the Royal Society,
for which he was most justly rewarded with its gold medal. The fame
of the new article spread rapidly throughout the world; science and
speculation seized upon it with equal eagerness; a thousand newspapers
promulgated its praises; it was immediately analysed, studied, and
tried in every possible way, so that it is now as well known and as
extensively used as if it had been in our possession for centuries.
The Icosandra Gutta is a large high tree, with a dense crown of
rather small dark green leaves, and a round smooth trunk. The white
blossoms change into a sweet fruit, containing an oily substance fit
for culinary use. The wood is soft, spongy, and contains longitudinal
cavities filled with brown stripes of gutta percha. The original method
of the Malays for collecting the resin consisted in felling the
tree, which was then placed in a slanting position, so as to enable
the exuding fluid to be collected in banana leaves. This barbarous
proceeding, which from the enormous demand which suddenly arose for the
gutta would soon have brought the rapidly rising trade to a suicidal
end, fortunately became known before it was too late, and the resin is
now gathered in the same manner as caoutchouc, by making incisions in
the bark with a chopping knife, collecting the thin, white, milky fluid
which exudes in large vessels, and allowing it to evaporate in the
sun or over a fire. The solid residuum, which is the gutta percha of
commerce, is finally softened in hot water, and pressed into the form
of slabs.
Grutta percha has many properties in common with caoutchouc, being
completely insoluble in water, tenacious, but not elastic, and an
extremely bad conductor of caloric and electricity. The name of
vegetable leather which has been applied to it, gives a good idea both
of its appearance and tenacity.
Its uses are manifold. It serves for water-pipes, for vessels fit for
the reception of alkaline or acid liquids which would corrode metal or
wood, for surgical implements, for boxes, baskets, combs, and a variety
of other articles. The wonder of the age, submarine telegraphy, could
hardly have been realised without it, as it is only by being cased
in so isolating a substance, and one so impermeable by water, that
the metallic wire is able to transmit the galvanic stream through the
depths of ocean from land to land.
Of all the dyeing substances which the tropical zone produces in such
endless variety, none is more important in a commercial point of
view than indigo. Various species of plants producing this beautiful
cerulean colour are found growing spontaneously in the warmer countries
of both hemispheres, but the _Indigofera tinctoria_ is most generally
cultivated. The knotty shrubby plant rises about two feet from the
ground; the leaves are winged like those of the acacia, smooth and
soft to the touch, furrowed above, and of a darker colour on the upper
than the under side. The small reddish flowers which grow in ears
from the axillæ of the leaves have no smell, and are succeeded by
long crooked brown pods, which contain small yellow seeds. The plant
requires a smooth rich soil, well tilled, and neither too dry nor too
moist. A child of the sun, it cannot be advantageously cultivated
anywhere except within the tropics, a higher mean temperature than
60° being absolutely necessary for its vegetation. The seed is sown
in furrows a foot apart from each other, and two or three inches in
depth. Sufficient moisture causes it to shoot above the surface in
three or four days, and it is usually fit for gathering at the end of
two months. When it begins to flower it is cut with a sickle a few
inches above the roots, and furnishes, after six or eight weeks, a
second crop. The cultivation of indigo would thus seem to be extremely
profitable, but the sun, which so rapidly improves and invigorates
the plant, calls forth at the same time a multitude of insects and
caterpillars, that prey upon the valuable leaves, and frequently
disappoint the planter’s expectations.
[Illustration: CUTTING THE INDIGO PLANT.]
All the intermediate shades of violet and purple may be obtained
from the mixture of red and blue, varying according to the different
proportions wherein these colours are applied. There are, however, some
few vegetable substances which yield a violet or purple dye, without
being combined with another colour, and of these logwood is the most
important. The stately tree which furnishes this valuable article of
commerce is a native of the western world, having been first discovered
in the swampy forests of Yucatan, and in the low alluvial grounds that
girdle the Bays of Campeachy and Honduras.
About the year 1661, logwood became in great request; and as the
indolent Spaniards to whom the country at that time belonged failed to
supply the market, several English adventurers, without first asking
permission, settled or squatted on the uninhabited coast of Yucatan,
and made the woods near Laguna de Terminos ring with the sound of their
industrious axe. Many years passed without the Spaniards taking any
notice of the intruders; but as these, growing bolder by sufferance,
began to penetrate farther into the country, to build houses and form
plantations, as if they had been masters of the soil, their jealousy
was at length aroused, and in 1680 the English settlers were forcibly
ejected. This triumph on the part of their adversaries was, however,
but transitory; and a few months after our sturdy countrymen were again
cutting their logwood as busily as ever, in spite of the enmity of man
and the innumerable hardships of their laborious occupation.
Their mode of life is thus quaintly described by Dampier in his Voyage
to the Bay of Campeachy:--‘The logwood-cutters inhabit the creeks of
the lagunes in small companies, building their huts by the creeks’
sides for the benefit of the sea-breeze, as near the logwood groves as
they can, and often removing to be near their business. Though they
build their huts but slightly, yet they take care to thatch them very
well with palmetto leaves, to prevent the rains, which are there very
violent, from soaking in. For their bedding, they raise a wooden frame,
three feet and a half above ground on one side of the house, and stick
up four stakes at each corner, to fasten their curtains, out of which
there is no sleeping for mosquitoes. Another frame they raise, covered
with earth, for a hearth, to dress their victuals; and a third to sit
at, when they eat it. During the wet season, the land where the logwood
grows is so overflowed that they step from their beds into the water,
perhaps two feet deep, and continue standing in the wet all day till
they go to bed again; but, nevertheless, account it the best season
for doing a good day’s labour in. Some fell the trees, others saw and
cut them into convenient logs, and one chips off the bark, and he is
commonly the principal man; and when a tree is so thick that after it
is logged it remains still too great a burden for one man, it is blown
up with gunpowder. The logwood-cutters are generally sturdy strong
fellows, and will carry burthens of three or four hundredweight. In
some places they go a-hunting wild cattle every Saturday to provide
themselves with beef for the week following. When they have killed a
beef they cut it into quarters, and taking out the bones, each man
makes a hole in the middle of his quarter, just big enough for his head
to go through, then puts it on like a frock and trudgeth home; and, if
he chanceth to tire, he cuts off some of it and throws it away.’
The entire freedom from all restraint which accompanied this wild and
adventurous life had such charms for Dampier’s bold and roving spirit,
that he sojourned for about a year among the rude wood-cutters of
Campeachy, and left them with the intention of again returning for a
longer stay.
Most of the red dye-woods are furnished by the Cæsalpinias, a genus
of plants belonging to the widespread family of the Leguminosæ, and
indigenous in both hemispheres. The _C. crista_, which furnishes the
best quality, commonly known under the name of Brazil wood, grows
profusely in the forests of that vast empire, preferring dry places
and a rocky ground. Its trunk is large, crooked, and full of knots;
at a short distance from the ground innumerable branches spring forth
and extend in every direction in a straggling manner. The branches are
armed with short strong upright thorns, the leaves are small, and never
appear in luxuriant foliage. The flowers are of a beautiful red colour,
and emit a fragrant smell. Both the thick bark and the white pithy part
of the trunk are useless, the hard close-grained heart being the only
portion impregnated with colouring matter. The wood is sometimes used
in turning, and is susceptible of a good polish, but its chief use is
as a red dye. By the addition of acids it produces a permanent orange
or yellow colour, while the crimson tints which it imparts are very
fleeting.
The first Europeans that settled on the banks of the Amazons found
that several of the Indian tribes that roamed about in their vicinity
painted their bodies with a showy orange-red colour. Their attention
was by this means attracted to the Arnatto (_Bixa orellana_), which
attains about the size of our hazel-tree. The heart-shaped leaves
are about four inches long, of a lighter green on the upper surface,
and divided by fibres of a reddish-brown colour; the rosy flowers are
succeeded by bristled pods somewhat resembling those of a chestnut,
which, bursting open when ripe, display a splendid crimson farina or
pulp, in which are contained thirty or forty seeds, in shape similar
to raisin stones. As soon as they have arrived at maturity the pods
are gathered, divested of their husks, bruised, immersed in water, and
after a few weeks beaten with sticks to promote the separation of the
pulp from the seeds. The turbid liquor is then strained, boiled to a
consistent paste, and finally formed into cakes, which are left to dry
in the sun. In England arnatto is generally used by the dyer to give a
deeper shade to the simple yellow. Being perfectly soluble in spirits
of wine, it is much used in this state for lacquering and for giving an
orange tint to the yellow varnishes. It is likewise employed in large
quantities as a colouring ingredient for cheese, to which it gives the
required tinge without imparting any unpleasant flavour or unwholesome
quality.
[Illustration: CINNAMON.]
[Illustration: CLOVE.]