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Rubber is a sticky, elastic solid produced from a milky liquid
called "latex," which has different
properties than the sap found in trees.
Although latex is found in the bark, roots, and stems, branches,
leaves, and fruit of over 400 different plants and trees, the bulk
is found, and extracted, from the inner
bark of the branches, and from the trunk, of the rubber tree. Quite
simply, it would not be cost-effective to extract the latex from
rubber producing plants, such as the dandelion, the milkweed, and the sagebrush. Just visualize some poor soul
laboring over one of these with a syringe!
Rubber, derived from the gum of a
tree, has existed since prehistoric
times. For example, fossils of rubber-producing plants date back
almost 3,000,000 years. Crude rubber
balls, discovered in ruins of ancient Incan
and Mayan civilizations in Central and in South America, are,
at very least, 900 years old. Natives of Southeastern Asia used
rubber, prepared from the "juice" of trees to waterproof their
baskets and jars. Even Columbus, on his second voyage to the New
World, observed Haitian natives playing with balls made from "the
gum of a tree."
Latex consists of tiny particles of liquid, solid, or semi-fluid material, that appears in the form
of a watery liquor, not to be drunk! The breakdown on this watery liquid is only about
33% rubber, with the remainder being, not surprisingly, water! When
the rubber particles in the latex join together, they form a ball of
rubber.
Rubber producing plants grow best within 10 degrees of the
Equator, where the climate is hot and moist, and the soil is deep
and rich. For this reason, the area of about 700 miles on each side
of the Equator is known as the "Rubber Belt." Brazil, from whence
the best, and top-producing rubber tree hails, is firmly planted
within the Rubber Belt. This Latino tree with a Latin name, Hevea brasiliensis, produces approximately
96% of the world's supply of natural rubber, and now is cultivated
in other Rubber Belt countries.
Most likely, the French, prior to the 1800s, were the first white
men to take advantage of rubbers' elasticity. They manufactured
"rubber bands" for use with their garters and their suspenders, to
help to keep their pants up. Rubber belts did not exist at that
time. |
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note:
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latex: 膠乳，乳液
sap: 樹(shù)液，汁液
extract: 提取
dandelion: 蒲公英
milkweed: 乳草屬植物
sagebrush: 山艾樹(shù)
gum: 樹(shù)膠
crude rubber: 天然橡膠
Incan and Mayan civilizations:
印加和瑪雅文化
semi-fluid:
半流體
breakdown: 分解
Hevea brasiliensis: 橡膠樹(shù) | |
