Natural rubber, Indiarubber or Caoutchouc are all names for the
solid elastic material isolated, one way or another, from the
‘milk’ or latex of various plants. Whilst these plants
tend to occur in the tropics, there are many which grow in the
temperate zones and also produce this material although not in
any commercial sense. Perhaps the most common source in the UK
is the dandelion – snap its stalk and the white fluid is
latex which will dry to give rubber.
The latex is therefore the white milk-like fluid which is obtained
by wounding the plant and in the case of the most common commercial
source today, the tree Hevea braziliensis, by cutting a sloping
incision in the outer bark from which the latex will ‘bleed’
and then refreshing the wound by removing slivers from the surface
of the cut on subsequent tapping days.
the word ‘rubber’ itself did not come into use until
the 1770’s (see J Priestly in the
time line) and it was another hundred or more years before
it was adopted by scientists who preferred the ‘classical’
caoutchouc. In the 20th Century the application of the one word
expanded in common usage to include an ever-growing range of synthetic
elastomers. It is interesting to look at the origins of the word
caoutchouc a little closer but first let us consider the name
of the trees from which this material comes as this also provides
an interesting story!
The ‘Rubber’ Tree
Frenando Hernandez produced a great survey of the natural resources
of Mexico in the 1570’s ("Rerum Medicarum Bovae Hispaniae
Thesaures") which was only published in 1649. Here
he wrote extensively about the rubber-producing tree which is
today identified as Castilla elastica. He wrote: "When the bark
is tapped a gum flows out which is called 'holli' by the
Indians....the gum is so resilient that, properly prepared and
shaped into round balls these balls can be used for the same
purpose as our Spanish inflated leather balls.
here for a larger picture.
In 1723, Father AJ de la
Neuville wrote of the peculiar gum (rubber) which the Indians
of French Guiana used to make various artefacts and ornaments.
From his description it seems likely that this gum was obtained
from a vine of the order of Apocynaceate – probably landolphia.
The Castilla elastica was also the tree described by la
Condamine and from this came the rubber samples which he sent
to France in the 1730’s but a decade later he saw the ‘syringe
tree’ and did not realise it was different. Almost certainly
he had not seen the original Castilla but had only heard reports
of it. It was this ‘syringe tree’ tree which François
Fresneau found in French Guiana and wrote about to la
Condamine and the Paris Academy of Science. By a pure fluke
he appears to have found the one and only Hevea braziliensis in
that country and it is not surprising that his drawings caused
confusion some time later! He did not give it its current name
but just referred to the ‘enema tree’ after the stories
of the uses to which the syringes prepared from the ‘syringe
tree’ were put.
In 1775 JCF Aublet published a book on the plants of French Guiana
and in it he recorded a ‘rubber tree’ which we now
know could not have been the same as Fresneau’s but at that
time, Aublet believed that his tree, la Condamine’s and
Fresneau’s were the same. He came up with the name Hevea
peruviana, thus giving la Condamine credit for his early discoveries.
With a second thought he then reasoned that, since he had not
seen la Condamine’s tree but only the ones in French Guiana,
he had better play safe so he re-named his tree Hevea Guyanensis
(its present name). This upset many people who objected to a ‘localised’
name being given to a tree found all over the north of South America.
At the same time, Aublet was castigating Fresneau for the poor
quality of his sketches which looked nothing like his (Aublet’s)
tree. It was left to the Dutchman, Arnoud Juliaans to study all
the literature and state the obvious – THERE WERE AT LEAST
TWO DIFFERENT TREES. (see 1780 below). In 1807 Persoon called
the ‘syringe’ or ‘enema’ tree Siphonia
elastica whilst in 1811 Willdenhow, Director of the Berlin Botanical
Gardens came up with the name Hevea braziliensis. The dispute
was only resolved in 1865/6 by Müller who suppressed Siphonia
in favour of Willdenhow’s name which illustrated the Aztec
origins of rubber technology and the geographical location of
the tree. It is now appreciated that Hevea braziliensis is almost
completely located south of the river Amazon in north-west Brazil,
north Bolivia and east Peru whilst other ‘rubber’
trees of the genus Hevea are located north of the river to a latitude
of about 6°N.
Finally, the seeds which Henry Wickham collected in 1876 were
from the Tapajos region of Amazonia, south of Santarem, and were
Hevea braziliensis, as were the seedlings of Robert Cross. By
coincidence Kew had acquired what proved to be the highest yielding
plants which gave the best quality rubber and, historically, had
the most appropriate name!
The Names For Rubber
There are four new-world native words for rubber and these are
written as Cauchuc (or caoutchouc), Hevea, Olli and Kik. It has
been said that there is a relationship between caoutchouc and
devil worship and sacrifice but before considering this, let us
deal with the three other words.
Kik is a word from the Mayan language of the Yucatan peninsula
and means ‘blood’ but it has never been used in the
west to refer to rubber.
Olli comes from the Nahuatl language of ancient Mexico and, because
of the locations of the various rubber-bearing trees, always refers
to the Castilloa elastica. This is obviously the root of the current
Mexican word for rubber – Ule.
Hevea was la Condamine’s word taken from the Equadorian
Indians for the rubber-bearing tree itself and has never been
used in modern times to mean rubber. The modern word for rubber
in Peru and Equador is jebe.
This brings us to Cauchuc/caoutchouc which is important in that
it is the basis for the current French, German, Spanish, Italian
and Russian words for the material – and is complicated
as it seems to have origins in at least four different languages.
The Maïnas Indians of Peru have the word meaning ‘juice
of a tree’ whilst other authorities have identified the
word with the Tupi Indians of the Brazilian Amazon and also the
word Caucciú from the Caribbean. Each could, of course,
be relevant depending on which explorer met which native! The
interpretation publicised by Vicki Baums’s eponymous novel
“Weeping Wood” is that of WH Johnson who claims that
caoutchouc is a corruption of caaocho, itself derived from Caa,
meaning ‘wood’ and o-cho meaning ‘to run’
Perhaps the final word should lie with The Kechuan language of
the Peruvian Incas as this was the most developed of four Indian
languages. Here the 1608 dictionary of Diego Gonzalez Holguin
translates cauchu as ‘he who casts an evil eye’ whilst
in 1653 Bernabé Cobo noted that the Mexican olli and the
Peruvian cauchuc refer to the same material obtained from Castilloa
elastica. It should be remembered that applications of rubber
to witchcraft, sorcery and ritual sacrifice (as well as the ball
game) predate its more utilitarian uses.
Other rubber-producing trees of historical interest are listed
below. For various reasons none challenged the Hevea braziliensis
which today produces virtually all the natural rubber used worldwide.
(Elastica and Ulei)
|The former found in central America and
Mexico, the latter in Peru and Brazil.
||From the Ceara region of Brazil.
||Found in Java and Malaysia.
||Creepers found mainly in the Congo basin.
||Found in West Africa.
Also of related note are:
A shrub producing
guayule which is regularly re-examined as a possible source
of ‘local’ natural rubber by the US. It is found
naturally in the arid regions of Mexico and the rubber has
to be solvent-extracted from the shrub.
||Found in Malaysia and Sumatra –
gives jelutong, used in chewing gum.
| Genus Dichopsis
percha (see the time chart).
Yields balata. First
harvested commercially in Guiana in 1863 and used for golf
balls, insulation etc. Today the Macushi Indians of Guiana
carve animals from it which are sold to sustain their rural
communities and lifestyle.