4. The Story of Rubber
Along the north coast of Haiti, particularly near Cap Haiti and Puerto Plata, there are scattered a few plantations devoted to rubber growing; and it is not without interest that Columbus on his first voyage landed at about this precise spot in December, 1492, and found the natives playing a game of ball made of rubber. He wrote: “The balls were of the gum of a tree, and although large, were lighter and bounced better than the wind balls of Castile.” This is apparently the first notice of the use of rubber, a substance now of world-wide importance, and derived from many other plants than the tree mentioned by Columbus. This is Castilla elastica, a native of certain islands of the West Indies and the adjacent mainland, and a relation of our common mulberry.
For over three centuries rubber, or caoutchouc as it was often called, was only of very casual use before the process of vulcanizing was discovered by Charles Goodyear, an American, in 1839. This combination of rubber with sulphur transformed a material much subject to heat and cold, and of almost no manufacturing value, into one from which hundreds of articles of daily use are now manufactured. Previous to this it had been used mostly, and in fact almost exclusively, as a waterproofing material for cloth, a process much developed by the firm of Charles Macintosh & Co., who appear to have taken out the first patent for a waterproofing process in 1791, in England. The rubber tree found by Columbus is still grown in considerable quantities and is a valuable source of rubber, but it has been greatly overshadowed by a Brazilian tree which now produces over two-thirds of all the rubber in the world.
This Brazilian tree, a native of the rich rain forests of the Amazon, is Hevea brasiliensis, and a relative of our common spurges of the roadsides and of the beautiful crotons of the florist, all belonging to the family Euphorbiaceæ. The first important notice of this rubber appears to be by the astronomer C. M. de la Condamine, who was on an astronomical trip to the Amazon in 1735. He described Para rubber, as it has since been called, and by 1827 the export of this gum had grown to 31 tons a year. In 1910 Brazil exported over 38,000 tons, nearly all of which was collected from wild trees. After the discovery of vulcanization the demand for all kinds of rubber increased by leaps and bounds and it became obvious that the wild trees, although tapped regularly, would not supply all of the necessary amount. For years the Brazilian Government protested the export of seeds or other means of growing the plant out of the Amazon, but in 1876 H. A. Wickam chartered a steamer and loaded her with 70,000 seeds of para rubber trees and some crude rubber, and had the ship passed by the Brazilian port authorities as loaded with “botanical specimens.” He safely transported the cargo to the Kew Gardens, London, where only about 4 per cent of the seeds ever germinated. From there the young plants were sent to India, where now, and in the Straits Settlements and the adjacent islands, there are huge plantations of para rubber. From the wildest speculation in rubber shares on the London Stock Exchange, which followed the successful introduction of the plant into British possessions, the industry has now settled down to be one of the most profitable in plant products of the East.
The rubber of both Hevea and Castilla is produced from the milky juice or sap of the trees and is actually a wound response. As the trees are tapped the latex, as the milky juice is called, runs out of the wound and upon reaching the air coagulates. This material is removed and a new wound made, a process which is repeated for several years. There is still work to be done upon the problem of how often plantation trees should be tapped to get the greatest flow of latex without injuring the tree, but in many plantations it is done every day or every other day in the season, some rubber planters allowing a resting period during leaf fall, others again tapping almost continually. The actual wound is made by removing just enough bark to induce a flow of latex, but not until the wound is completely healed, a process taking from four to six years, can that particular part of the bark be cut again. With almost daily tappings the problem of finding fresh pieces of bark into which the cut may safely be made has been developed into a fine science. In the wild trees of Brazil it is still done by natives, probably rather wastefully. Rubber plantations in the tropical regions of Asia now total over a million acres, as compared to only slightly over 200,000 acres in the American tropics and from all other non-Asiatic sources. Of this probably 100,000 acres are in Africa. At the present time nearly half the world’s supply of rubber comes from these plantations, the balance still coming from Brazil.