362 



SCIENCE-GOSSIP. 



the valley of the Amazon, and the area known to 

 produce this rubber in its wild state is more than 

 nine times the size of Great Britain. This region 

 not only produces the best quahty of indiarubber, 

 but more than one-third of the world's supply. 

 The better qualities of this rubber are now so 

 eagerly sought after for the markets of the 

 United States and Germany, that this important 

 industry is no longer a monopoly of this 

 country. The plant has been introduced into 

 India on a large scale. It is now well established 

 in Singapore, Java, Africa, and the West Indies. 

 It is no easy task to raise rubber plants which are 

 indigenous to ore place in another, even where 

 the conditions are favourable so as to make them 

 successfully productive. Yet, commercially speak- 

 ing, the Para rubber tree is the most profitable 

 that can be grown in the East. 



Central American rubber, including that 

 exported from Mexico, Guatemala, Panama and 

 the western slopes of the Andes as far as Peru, is 

 not much inferior to that of Para. It is produced 

 from Castilloa elasiica, one of the nettle family. 

 With balls made from the rubber of this tree, 

 Columbus noticed the natives playing when he 

 landed in America 400 years ago, and similar 

 rubber balls are still played with by the Indians 

 in the valley of the Amazon. In fact, the use of 

 rubber for domestic appliances was also familiar to 

 the natives of Central and South America long 

 before it was known to European nations. 

 Castilloa elastica has an extensive geographical 

 range, and is capable of existing under varied 

 climatic conditions. It is a large-sized tree 

 sometimes growing to a height of 180 feet, with 

 a circiunference of 15 feet. It grows wild along 

 the coasts of Mexico from the sea-level to a height 

 of 1,500 feet. A dry or rainy climate is equally 

 suited to it, but a high and equable temperature 

 which never falls below 60° Fahr. is essential. 

 Plantations of this tree have been established in 

 Mexico, and profitable harvests of rubber collected 

 from them. One of the most important of these 

 plantations is La Esmeralda. Sir Henry Nevill 

 Dering, the British Minister in Mexico, states 

 that rubber plantations of 100,000 trees do not cost 

 more for cultivation during five years than ,£2,500, 

 while the yield from the same the first time the 

 juice is drawn would realise about £12,000, and 

 this does not include the profit from vanilla, 

 bananas, cacao, and other productive plants which 

 can be cultivated in the space between the rubber 

 trees. He estimates that a profit of 400 per cent, 

 per annum might be drawn. His calculations, . 

 however are based upon trees only five years old, 

 which is a much younger age than is advocated to 

 tap them, although a fair yield may be obtained. 



The Ceara rubber tree is another American 

 plant, and probably the only one that offers any 

 inducement for cultivation in other than their 



native countries. Neither this nor the Central 

 American rubber has as yet been able to be culti- 

 vated with profit in the East. Ceara rubber is 

 produced from ManiJiot glaziovii, another of the 

 spurgeworts and named after Dr. Glaziou, who 

 first sent specimens- to this country. The tree is 

 a native of north-east Brazil, and grows to a 

 height of about 40 feet. From 200 to 300 tons of 

 the rubber of this tree are imported annually to 

 this country, but the quality of it varies according 

 to the mode of tapping the trees and the care 

 taken in its preparation. When pure it ranks 

 next to Para rubber in value. 



The only other American rubber of any impor- 

 tance is yielded by Hancornia speciosa, a dwarf tree 

 with somewhat the habit of a birch and belonging 

 to the dogbane family. When compared with the 

 others, the possibility of acclimatising it for 

 cultural purposes is small. 



The most promising source of rubber now is 

 Africa, where the development of the industry in 

 certain parts is one of the most remarkable inci- 

 dents in recent years. Up till lately all the 

 rubber-yielding plants in Africa belonged to one 

 gemis, Landolphia of the dogbane family. 



Since the discovery in 1894 of the valuable rubber 

 tree, Kicksia africana, also one of the dogbanes, these 

 practical difficulties have disappeared. The tree 

 was first discovered in the colony of Lagos, and 

 has since been found to be widely distributed in 

 West Africa. It grows nearly 50 feet high, and 

 each tree is estimated to yield annually about two 

 pounds of rubber. The quantity collected in 

 Lagos alone during 1895 attained a value of 

 £270,000, representing an export of 2,270 tons. 

 Owing, however, to the destructive methods, of 

 the natives in extracting the juice, the exports 

 have greatly fallen off. The commercial value of 

 the Lagos silk rubber, as it is called in the trade, 

 stands high, and experiments are being made to 

 establish regular plantations to try and make the 

 industry permanent. The rubber of the Kicksia 

 is of good quality, and the tree grows more vigo- 

 rously than any other rubber-yielding tree. It is 

 said that, after.eight years, the Kicksia is in a condi- 

 tion to yield marketable rubber, and in West 

 Africa the tree is more suitable for cultivation 

 and more likely to be adopted than any of the 

 American species. 



More x'ecently still another new source of rubber 

 has been discovered in the Congo State. It is 

 obtained from the underground stems of a small 

 and somewhat herbaceous plant, Carpodinus 

 lanceolatus, another of the dogbanes. The under- 

 ground stems are rasped in water and yield rubber 

 of an excellent quality. This plant is also 

 available for cultivation, and is expected to give 

 better retimis than any of the rubber trees 

 hitherto in use. It is probable, too, that other 

 rubber-yielding plants may yet be discovered in 



