_Courtesy of the United States Rubber Co._]
The way they gather this rubber is very interesting. When it comes from
the tree it is nothing but a milky juice. The natives of South America
soon discovered that the white man was willing to pay them beads and
other trinkets for chunks of this rubber, so they became active in
gathering it.
[Illustration: ON THE BANKS OF THE RIO GUAPORE--BRAZIL
_Courtesy of the B. F. Goodrich Co._]
What is a Rubber Camp Like?
In this locality the rubber harvest commences as soon as the Amazon
falls which is usually about the first of August. When this date
approaches bands of natives set out from their primitive homes and go,
in many instances, hundreds of miles into the forest lowlands. There,
within easy reach of the rubber trees, they set up their camp and the
actual work of harvesting the rubber crop begins. It usually covers a
period of about six months, extending from August to January or
February.
The camps are usually great distances from the nearest town and
procuring supplies is not only difficult but very expensive as well. The
natives build their huts out of small poles covered with palm thatch and
live in little colonies while the rubber harvest is going on. The
Brazilian name for a rubber gatherer is “seringuero.”
[Illustration: RUBBER GATHERER’S HUT NEAR THE AMAZON
_Courtesy of the B. F. Goodrich Co._]
A roof and floor with the flimsiest of walls, set up on piling for
coolness, defense against animals and insects, and to keep the building
dry during flood season, forms the home of the rubber gatherer. The more
pretentious and better furnished home of the superintendent of the
“estate,” together with the storehouses, etc., are called the
“seringal.”
The buildings are usually grouped together at a favorable spot on the
banks of the Amazon or one of its tributaries.
Furniture is of the most primitive type. The laborers and their families
sleep in hammocks or on matting on the floor. Food is largely made up of
canned goods and the ever-present farina, a sort of tapioca flour.
The climate of the South American rubber country is usually fatal to
white men, and even among the Indians the fevers, the poisonous insects
and reptiles, and the other perils of a tropical forest cause a high
death rate. The production of South American rubber is limited by a
shortage of men rather than a shortage of trees.
In December the rainy season begins. The waters of the Amazon begin to
rise and the work ceases. The superintendent and many of the workers go
down the river to Para and Manaos or to villages on higher ground.
However, a number of the laborers usually remain in the huts, loafing
and fighting the animals and insects that seek refuge from the rising
waters. They have but little to eat, and during the entire season
practically no communication with the outside world.
[Illustration: A HOME OF THE RUBBER GATHERERS
_Courtesy of the United States Rubber Co._]
At the end of the rainy season, early in May, the laborers return to
their task. The quick-growing vegetation has filled the estradas and
this must be cleared away and perhaps new estradas opened. An estrada is
simply a path leading from one Hevea tree to another and circling back
to camp. Each estrada includes about one hundred of the scattered
Heveas.
After having established themselves in camp the natives take up their
monotonous round, which is followed day after day as long as the rubber
trees continue to yield their valuable sap. When the seringuero starts
out he equips himself with a tomahawk-like axe having a handle about
thirty inches long. This is called a “macheadino.”
[Illustration: TAPPING HEVEA RUBBER TREE--BRAZIL
_Courtesy of the United States Rubber Co._]
How is Rubber Gathered by the Natives?
The trees are tapped very much like maple syrup trees. Only the juice is
found between the outer bark and the wood. So these men make a cut in
the tree through the bark, almost to the wood. A little cup is then
fastened to the tree with a piece of soft clay to press the cup against
it, and the juice runs into this cup. Sometimes they have from ten to
thirty cups on one tree and the average yield of a tree is ten pounds of
rubber a year.
Some two hours after the tapping is done the flow entirely ceases and
the tree must be tapped anew to secure a fresh flow.
The film of rubber that forms on the inside of the cup and the bits of
rubber remaining on the tree are collected and sold as coarse Para.
[Illustration: ON THE BANKS OF THE AMAZON
_Courtesy of the B. F. Goodrich Co._]
[Illustration: GATHERING THE RUBBER MILK--BRAZIL
_Courtesy of the United States Rubber Co._]
[Illustration: HOW THE RUBBER MILK DRIPS FROM THE GASH IN THE
TREE--BRAZIL]
The rubber gatherer carries in addition to a macheadino and many small
tin cups, a larger vessel for gathering the liquid and carrying it to
camp. One man will tap as many as 100 trees in a single morning and then
cover the same ground again in the afternoon or on the following
morning, gathering the sap that drips slowly from the cuts made in the
trees. On these journeys the harvester frequently travels long distances
over paths so buried by the undergrowth of the jungle that they are
almost invisible to the untrained eye. On such expeditions rubber
gatherers usually go armed with rifles to protect themselves against
wild animals, reptiles and savage Indians.
[Illustration: A PLANTATION IN BORNEO
_Courtesy of the B. F. Goodrich Co._]
How is Rubber Smoked?
After the juice has been gathered in this way, the native builds a fire;
over it he places a cover shaped like a large bottle with the bottom
knocked out of it. This fire is built of oily nuts found in the forest,
and the thick smoke arises through what would be the neck of the bottle.
[Illustration: SMOKING RUBBER ON THE LOWER AMAZON
_Courtesy of the United States Rubber Co._]
With a stick shaped something like the wooden shovels used at the
seashore, he dipped into the milky juice in the bowl, then turned this
stick or paddle around very rapidly in the smoke until the juice baked
on the paddle. He then added more juice and went through the same
operation again and again until there were between five and six pounds
of rubber baked on this paddle. He then cuts this off with a wet knife
which made it cut more rapidly. That formed what is called a rubber
“biscuit,” and he then started over again for his next five or six
pounds. Later, as the demand for these “biscuits” increased, instead of
the native using the paddle, he erected two short fence-like affairs
about six feet apart, but parallel with each other, and in between was
the smoky fire. Then he obtained a long pole, stretched it across these
two rails and poured a small quantity of this juice on this pole, over
where the smoke came in contact with it, and rolled the pole around
until this juice was baked, adding more, until, instead of a small five-
or six-pound “biscuit,” he would get an immense ball. In order to get
this off his pole, he would jog one end of the pole on the ground until
the “biscuit” would slide off. This is the way crude rubber first came
into our market and the way it comes today.
[Illustration: SMOKING RUBBER--UPPER AMAZON
_Courtesy of the United States Rubber Co._]
How was Vulcanizing Discovered?
Up to this time, these “biscuits,” when exposed to heat, would become
very soft and sticky, and when exposed to the cold, would become hard
like a stone.
[Illustration: REMOVING BISCUIT FROM POLE AFTER SMOKING
_Courtesy of the United States Rubber Co._]
There was an American by the name of Charles Goodyear who had heard how
the natives of the rubber-growing countries used this milky juice in
many ways for their own benefit. One use they put it to was the
waterproofing of their cloaks. How could this be done so that our
clothing would be made water-tight and yet not be sticky in summer or
stiff in winter? Goodyear devoted a great deal of his time to solving
this problem, and, like many other great inventors, he passed through
many trials. His many failures caused his friends to forsake him and he
was put in prison for not paying his debts. He persisted in his quest,
however, and it was accident at last that opened the way to discovery of
the processes of vulcanization for which Goodyear was seeking.
[Illustration: INDIAN WATERPROOFING CLOTH BY “PAINTING” IT WITH RUBBER
“MILK”--BRAZIL
_Courtesy of the United States Rubber Co._]
At Woburn, Mass., one day, in the spring of 1839, he was standing with
his brother and several other persons near a very hot stove. He held in
his hand a mass of his compound of sulphur and gum, upon which he was
expatiating in his usual vehement manner, the company exhibiting the
indifference to which he was accustomed. In the crisis of his argument
he made a violent gesture, bringing the mass in contact with the stove,
which was hot enough to melt India-rubber instantly; upon looking at it
a moment afterwards, he perceived that his compound had not melted in
the least degree! It had charred as leather chars, but no part of the
surface had dissolved. There was not a sticky place upon it. To say that
he was astonished at this would but faintly express his ecstasy of
amazement. The result was absolutely new to all experience--India-rubber
not melting in contact with red-hot iron! He felt as Columbus felt when
he saw the land bird alighting upon his ship and the driftwood floating
by. In a few years more his labors were crowned with success.
This great invention made it possible for us to have rubber boots and
rubber shoes and many other things made of rubber.
[Illustration: _Courtesy of the United States Rubber Co._]
Up to this time, all the rubber was called Para rubber, named from the
town of Para in Brazil, from which all rubber was shipped. The
full-grown tree is quite large, ranging sixty feet and over in height
and about eight feet around the trunk. It has a flower of pale green
color and its fruit is a capsule containing three small brown seeds,
with patches of black. These seeds lose their life very quickly, so a
great deal of care is necessary to pack them if they are wanted to plant
in another place. The safest way is to lay them loosely in a box of dry
soil or charcoal.
[Illustration: RUBBER TWIGS
_Courtesy of the United States Rubber Co._]
The rubber tree grows best in rich, damp soil and in countries where the
temperature is eighty-nine to ninety-four degrees at noon-time and not
less than seventy-four degrees at night, and where there is a rainy
season for about six months in the year, and the soil and atmosphere is
damp the year round.
The name of this species of tree is Hevea, but many years ago it was
called Siphonia on account of the Omaqua Indians using squirts made of a
piece of pipe stuck into a hollow ball of rubber.
How did Rubber Growing Spread to Other Places?
Back in the seventies an English botanist, Wickham by name, smuggled
many Hevea seeds out of Brazil. The tree was found to grow well in the
Eastern tropics and today the rubber plantations of Ceylon, Borneo, the
Malay Peninsula and neighboring regions are producing more than half of
the world’s supply of crude rubber. Here the natives work under pleasant
climatic conditions and the trees under cultivation grow better and
yield better than in the forest.
On these plantations, rubber trees are cultivated just the same as other
crops. All weeds are removed and great care is used with the young
trees. Low-growing plants which absorb nitrogen from the air which
enriches the soil, such as the passion flower and other sensitive
plants, were planted around these small rubber trees, for it was found
that when the weeds were removed to give the trees a chance to grow, the
ground became hard and dry.
[Illustration: _Courtesy of the United States Rubber Co._]
The method of tapping is different, too. Instead of ten to thirty taps,
a series of cuts the shape of a V is made on four sides of the tree,
from the bottom up to as high as a man can reach, and a cup placed at
the point of the V. Another way is to make one long cut down the tree
and then cut out slanting channels about one foot apart into this, and
put a cup at the bottom of the long cut; another is making a spiral
around the tree with the cup at the bottom.
How is Rubber Cured on Modern Plantations?
With these big plantations some other way to cure the rubber had to be
devised from the smoking process used in curing the native rubber which
comes from South America. The milky juice is emptied from the cups into
a tank and lime juice is added and it is then allowed to stand. The
juice, as it comes from the tree, contains considerable water: the lime
juice is added to separate the rubber from the water.
[Illustration: A YOUNG RUBBER PLANTATION
_Courtesy of the United States Rubber Co._]
Sometimes separators are used much like our cream separators; in fact,
the whole process and the appearance of the interior of these rubber
“dairies” very much resembles our own dairies where real milk is made
into butter, curds or cheese.
Para, at the mouth of the Amazon, and Manaos, a thousand miles up, are
both modern cities of more than one hundred thousand population. They
have schools, churches, parks, gardens and museums, and, except for the
Indians, certain peculiarities in architecture and the ever-present odor
of rubber, they differ but little from our northern cities of equal
size. Here the rubber markets are located and here the rubber is
carefully examined, graded, boxed and shipped to New York or Liverpool.
Plantation rubber usually comes in the form of sheets of various shapes
and sizes. The rubber shown here is in oblong sheets. Sometimes it is in
the form of “pancakes” or in “blocks.” Often, after being coagulated, it
is smoked, and “smoked plantation sheet” is, next to Para, the best
rubber obtainable.
[Illustration: _Courtesy of the United States Rubber Co._]
How is Crude Rubber Received Here?
Crude rubber is received in many forms under various names. There are
more than three hundred standard kinds, depending on source and method
of handling; _e. g._, “Sernamby” is simply bundles of Para tree scrap
and scrap from the cups where milk has cured in the open air. “Guayule”
is a resinous rubber secured from a two-foot shrub that grows on the
arid plains of Texas and Northern Mexico.
Our picture shows a bin of crude up-river Para the finest rubber known.
Every “biscuit” or “ham” has been cut in two to find out whether the
native has loaded it in any way.
[Illustration: ANOTHER CEYLON TAPPING METHOD--THE HERRINGBONE
_Courtesy of the United States Rubber Co._]
How is Rubber Prepared for Use?
Now that we have rubber so that it can be used, we find there are a
great many operations necessary between gathering the crude rubber and
finally the finished rubber coat or shoe. These various operations are
called washing, drying, compounding, calendering, cutting, making,
varnishing, vulcanizing and packing and each one of these main
operations requires several smaller operations.
The grinding and calendering department is the one in which the crude
rubber is washed, dried, compounded and run into sheets ready to be cut
into the various pieces which constitute a boot or shoe.
[Illustration: RUBBER MARKET IN MANAOS
_Courtesy of the B. F. Goodrich Co._]
The cultivated rubber comes practically clean, but the crude rubber
“biscuits” contain more or less dirt and foreign vegetable matter which
have to be removed. The rubber is softened in hot water for a number of
hours and then passed through the corrugated rolls of a wash mill in
which a stream of water plays on the rubber as it is thoroughly
masticated and formed into thin sheets. These sheets are taken to the
drying loft. Here they are hung up so that the warm air can readily
circulate through them and are allowed to remain from six to eight
weeks, until every trace of moisture has been removed. The vacuum dryer
is used where rubber is wanted dry in a short space of time. This is a
large oven containing shelves. The wet sheets of rubber are cut in
square pieces, placed on perforated tin pans and loaded into the dryer,
which will hold about eight hundred pounds of rubber. The doors are
closed, fastened, and by the vacuum process the water is extracted,
leaving the rubber perfectly dry in about three hours’ time.
[Illustration: SPECIAL DESIGNED MACHINE FOR CUTTING RUBBER
_Courtesy of the United States Rubber Co._]
[Illustration: TAPPING HEVEA RUBBER TREE ON CEYLON PLANTATION
_Courtesy of the United States Rubber Co._]
[Illustration: SOFTENING VATS
_Courtesy of the B. F. Goodrich Co._]
After the rubber is dry, and has been tested by the chemist, it goes to
the grinding mills where it is refined on warm rolls and made ready for
the compounding or mixing. It is impossible to make out of rubber alone,
shoes or other products that will withstand extreme changes in
temperature; certain amounts of sulphur, litharge and other ingredients
are necessary in combination with the pure rubber to give a satisfactory
material. The gum from the grinding mills is taken to the mixing mills,
where, between the large rolls, the various materials are compounded
into a homogeneous mass. The compounded rubber goes from the mixing
mills to refining mills, to be prepared for the calenders.
[Illustration: _Courtesy of the United States Rubber Co._]
Automobile, motorcycle and bicycle tires, belting, footwear and many
other rubber articles must have a base or backbone of cotton fabric, and
in order that the fabric may unite firmly with the rubber it must be
“frictioned” or forced full of rubber. This is done by drawing it
between enormous iron rollers, rubber being applied on its surface as it
passes through. The pressure is so great that every opening between the
fibers of cotton, every space between threads is forced full of rubber.
[Illustration: THE MILL ROOM
_Courtesy of the B. F. Goodrich Co._]
The fabric is then ready to go with the milled rubber to the various
departments of the factory to be incorporated into rubber goods. The
calender is also used to press rubber into sheets of uniform thickness.
How are Rubber Shoes Made?
In making footwear, the linings and such parts as can be piled up layer
on layer are cut by dies, usually on the large beam-cutting machines,
commonly seen in leather shoe factories. The uppers are cut by hand from
the engraved sheets, while metal patterns are used on the plain stock.
The soles are cut by specially designed machines. The sheets of rubber
from which the uppers and soles are cut are at this stage of the work
plastic and very sticky. It is necessary on this account to cut the
various pieces one by one and keep them separate, by placing them
between the leaves of a large cloth book. In an ordinary rubber shoe
there are from twelve to fifteen pieces, while in a common boot there
are over twenty-five pieces.
[Illustration: MAKING RUBBER BULBS
_Courtesy of the B. F. Goodrich Co._]
The various pieces are next delivered to the making department, where
they are fitted together on the “lasts” or “trees” in such a way that
all the joints and seams are covered and the lines of the shoe kept
exactly. Considerable skill is required to do this, as all the joints
and seams must be rolled down smooth and firm to ensure a solid boot or
shoe. The goods are all inspected before they are loaded on the iron
cars to go to the varnishing department, where they receive the gloss
which makes them look like patent leather.
[Illustration: MAKING STRAIGHTLINE RUBBERS]
[Illustration: IN THE TRUCK TIRE STOCK ROOM]
[Illustration: MAKING GARDEN HOSE (WRAPPED CONSTRUCTION)]
[Illustration: INSPECTING AUTOMOBILE INNER TUBES
_Courtesy of the B. F. Goodrich Co._]
[Illustration: BELT PRESS AND ROLL OF CONVEYOR BELT]
[Illustration: “BUILDING” WATER BOTTLES]
[Illustration: VULCANIZING TRUCK TIRES]
[Illustration: INSULATED WIRE READY FOR SHIPMENT
_Courtesy of the B. F. Goodrich Co._]
From the varnishing department the shoes are taken to the vulcanizers,
which are large ovens heated by innumerable steam pipes. The shoes
remain in these vulcanizers from six to seven hours, subjected to
extreme heat. This heating or vulcanizing process fixes the elasticity
of the rubber, increases its strength enormously and unites the parts in
such a way as to make the shoe practically one piece.
The shoes next go to the packing department, where they are taken off
the “lasts,” inspected, marked, tied together in pairs, sorted and
packed. They are then sent to the shipping department to be shipped
immediately or stored in one of the spacious storehouses.
How are Automobile Tires Made?
In making tires, the strips of fabric are built together about a steel
core to form the body or carcass of the tire. The beads are also added.
The side strips, the breaker strip and finally the tread are applied.
All of these pieces are sticky, and as they are laid together and rolled
down by small hand rollers they adhere to each other, and when the tire
is completed it looks very much like the tires you see on automobiles,
but it is not yet vulcanized. The rubber is much like tough, heavy
dough--there is not much stretch to it and in a cold place it would
become hard and brittle.
The tire on its steel core is taken to the mold room and placed in a
steel box or mold, shaped to exactly enclose it. It is then placed with
many others on a steel frame and lowered into a sort of a well or oven,
where it remains for a time under pressure in the heat of live steam,
after which it is removed, a finished tire.
Vulcanization is simply the heating of the rubber mixed with
sulphur--this causes a chemical change in the substance; it becomes
tougher, more elastic and less affected by heat and cold.
This process, discovered in 1839, made rubber the useful substance it is
today. The discoverer, Charles Goodyear, to whom we referred before, was
never connected in any way except by name with any of the manufacturers
of the present day, but his discovery was the real beginning of a great
industry.
* * * * *
How did the Expression “Before you can say Jack Robinson” Originate?
Jack Robinson was a man in olden days who became well known because of
the shortness of his visits when he came to call on his friends,
according to Grose, who has looked up the subject very carefully. When
the servants at a home where Jack Robinson called went to announce his
coming to the host and his assembled guests, it was said that they
hardly had time to repeat his name out loud before he would take his
departure again. Another man, Halliwell, who has also investigated the
development of the expression, thinks that it was derived from the
description of a character in an old play, “Jack, Robes on.”
It is also interesting to learn that the sandwiches which we all enjoy
so much at picnics are so called because of the fact that an English
nobleman, the Earl of Sandwich, always used to eat his meat between two
pieces of bread.
What is an Aerial Railway Like?
Wonderful ingenuity has been shown in contriving a means to enable
people to ascend the Wetterhorn Mountain in Switzerland. The sides of
the mountain are so irregular and rough in their formation that it was
found impossible to build even the incline type of railway, such as is
usually resorted to where the ascent to a mountain is particularly
steep. So the engineers who studied the problem finally contrived two
huge sets of cables, securely fastened at the top, and fixed to a
landing place a short distance from the base of the mountain. Cars,
holding twenty passengers each, are carried up and down these cables,
one car balancing the other, by means of a cable attached to each, which
passes around a drum at the top.
[Illustration: THE WETTERHORN AERIAL RAILWAY
_Reproduced by permission of The Philadelphia Museums._]
There is probably no railway in all Europe upon which travel affords
more wonderful scenery than this trip, suspended in the air, up the side
of the Wetterhorn Mountain, the three peaks of which are all
considerably more than two and a quarter miles high.
Why are They Called “Newspapers”?
Although something like an official newspaper or government gazette
existed in ancient Rome, and Venice in the middle of the sixteenth
century also had official news sheets, the first regular newspaper was
published at Frankfort in 1615. Seven years later the first regular
newspaper appeared in England.
It was customary to print the points of the compass at the top of the
early single-sheet papers, to indicate that occurrences from all four
parts of the world were recorded. Before very long, the publisher of one
of the most progressive papers rearranged the letters symbolic of the
points of the compass, into a straight line, and printed the word NEWS,
and in a very short time practically every newspaper publisher decided
to adopt the idea.
It is interesting to find that American colonies were not far behind
England in establishing newspapers, and equally interesting to know that
the most remarkable development of the newspaper has been in the United
States, where, in proportion to population, its growth and circulation
has been much greater than in any other country. Practically a half of
all the newspapers published in the world are published in the United
States and Canada.
Every trade, organization, profession and science now has its
representative journal or journals, besides the actual newspapers and
magazines of literary character, and Solomon’s remark might be
paraphrased to read: “To the making of newspapers there is no end.”
The great and rapid presses of recent years, the methods of mechanical
typesetting and the cheapness and excellence of photographic
illustrations, have all been necessary elements of the great sheets and
enormous circulations of the present day, and the twentieth century
newspaper is one of the greatest achievements in the whole field of
human enterprise.
How Did the Cooking of Food Originate?
As soon as man found that he could produce fire by friction, as the
result of rapidly rubbing two sticks together, he began to have
accidents with his fires, just as we do today. And it was probably
because of one of these accidents, in which some food was cooked quite
unintentionally, that primitive man made the great discovery that most
of the meats and fruits and roots that he had been accustomed to eating
raw, were far better if they were put in or near the fire for a while
first.
How Far Away is the Sky-Line?
Unless you happen to be of the same height as the person standing next
to you, the sky-line is a different distance away from each of you, for
it is really just a question of the distance the eye can see from
different heights above the sea-level. A person five feet tall, standing
on the beach at the seaside, is able to see about two and three-quarter
miles away, while one a foot taller can see about a quarter of a mile
further.
A person on the roof of a house a hundred feet high is able to see more
than thirteen miles away, on a clear day, and a forty-two mile view may
be enjoyed from the top of a mountain a thousand feet high. The aviator
who goes up to a level a mile above the sea is able to see everything
within a radius of ninety-six miles and the further up he goes the
larger the earth’s circle becomes to him.