384 CAOUTCHOUC, OR INDIA RUBBER. 



ing to the Cichoracese, Lobeliacese, Apocynacese, and Asclepiadacese. 

 Referring to the former, the Indian caoutchouc is principally obtained 

 from the natural family Artocarpacese ; whilst the American is derived 

 from trees classed among the Euphorbiacese. The chief source of the 

 " East India " or " Java rubber," large quantities of which have during 

 late years been imported into this country, is the Ficus elastica, 

 known also as the Assam caoutchouc tree. The Ficus elastica, again, 

 belongs to a family of plants which yield in abundance a milky juice, 

 possessed of various and singular properties in common with the hydro- 

 carburet emulsion of the order Euphorbiaceee. This remarkable tree is 

 described as attaining the size of an English sycamore, although it is 

 frequently met with of gigantic proportions. Trees have been found to 

 measure 80 to 100 feet in height, whilst the area covered by their expand- 

 ing branches has exceeded 150 feet in diameter. 



The Ficus elastica is also indigenous to Assam, in the districts between 

 the Burrampooter and the Bootan hills. It has a preference for rocky 

 chasms, where its roots are plunged among the debris of mountains and 

 vegetation. It has been calculated from authentic surveys that there are 

 from forty to fifty thousand trees of this class within a length of 30 by 8 

 miles of forest near Eerozepoor, in the district of Chardwar, in Assam ; and, 

 so far as has yet been determined, the geographical range of the tree in this 

 country is between 25 deg. 10 min. and 27 deg. 20 min. North latitude, and 

 90 deg. 40 min. and 95 deg. 30 min. East longitude. It is a tree growing 

 with great rapidity, attaining a height of 20 to 30 feet in a growth of five 

 years only. Its leaves are well formed, smooth, polished, and of a lustrous 

 green. From the larger branches, roots descend to the earth, as in the case 

 of several members of the same family, Ficus indica. 



In addition to the Ficus elastica, India has other trees also yield- 

 ing caoutchouc. We may quote the jack-tree, Artocarpus integrifolia ; 

 the banyan tree, Ficus indica; and the pippula tree, Ficus religiosa. East- 

 ward of Bengal other sources have been discovered : the Luti Aru, 

 a description of climbing apple, called Sadal Kowa, abounds in a milky 

 sap containing a large proportion of caoutchouc. The Urceola elastica, 

 first described by Dr Roxburgh as the chief source of caoutchouc in India, 

 yields it in great abundance. 



The late Dr Royle, who specially studied this question, states that 

 in the East " there might be any quantity of the article procured from a 

 great variety of plants, if the natives could only be induced to collect it 

 with sufficient care." 



The American caoutchouc is chiefly obtained from a tree belonging 

 to the Euphorbiaceee family, and named the Siphonia elastica. This tree 

 abounds on the banks of the Amazon and its tributaries. It attains a con- 

 siderable height, is perfectly straight, and is characterised by having no 

 branches except at the summit, where they form a conical crown ; its leaves 

 resemble those of the manioc, are coriaceous, and highly polished on both 

 sides. An oil is also extracted from its seeds. 



Caoutchouc is extracted from the various trees already mentioned, by 



