Naturalisation in Extra-Tropical Countries. 205 



like abutments, some of which extended 20 feet from the tree. 

 Several persons could conceal themselves in the large crevices of 

 the trunk, while the main-branches stretched across a space of about 

 100 feet. A kind of caoutchouc can be obtained from this tree. A 

 still more gigantic Fig-tree of Queensland is F. colossea (F. v. M.) f 

 but it may not be equally hardy, not advancing naturally to extra- 

 tropical latitudes. This reminds us of the great Council-tree, F. 

 altissima, from Java, where it grows in mountains on calcareous 

 ground. F. eugenioides (F. v. M.), from North- and East-Australia, 

 attains a height of 100 feet, and produces also columnar air-roots. 

 It is comparatively hardy, reaching extra-tropic latitudes. 



Ficus elastica, Roxburgh.* 



Upper India, to the Chinese bouiidry, known as far as 28 30 

 north-latitude, extending- to Burmah and the Malayan Islands. A 

 large tree, yielding its milk-sap copiously for the kind of caoutchouc 

 called Assam-Rubber. Roxburgh ascertained 80 years ago, that 

 india-rubber could be dissolved in cajaput-oil (very similar to 

 eucalyptus-oil), and that the sap yielded about one-third of its 

 weight of caoutchouc. This tree is not of quick growth in the 

 changeable and often dry climate of Melbourne ; but there is every 

 prospect, that it would advance very rapidly in any mild humid 

 forest-gullies, and that copious plantations of it there would call 

 forth a new local industry. This tree has grown in Assam to 112 

 feet with 100 aerial roots in thirty-two years [Markham]. In 

 moist warm climes, according to observations in Assam by Mr. 

 Gustave Mann, branches lopped off and planted will speedily 

 establish themselves. Single branches attain a length of 50 feet ; 

 the root-crown will attain a diameter of 200 feet exceptionally 

 [Haeckel]. The import of caoutchouc into the United Kingdom 

 in 1884 amounted to 198,000 cwt., representing a value of 2,266,000,. 

 of which F. elastica must have furnished a considerable proportion; 

 in 1883 the value of unworked rubber imported there was estimated 

 at 3,500,000 [J. Gr. Baker]. Markham and Collins pronounce 

 the caoutchouc of F. elastica not quite so valuable as that of the 

 Heveas and Castilloas of South -America. Heat and atmospheric 

 moisture greatly promote the growth of F. elastica. Like most 

 other Fig-trees, it is easily raised from seed. A tree of F. elastica 

 is tapped in Assam when twenty-five years old. After fifty years 

 the yield is about 40 Ibs. of caoutchouc every third year, and lasts- 

 till the tree is over 100 years, old. The milky sap, flowing from 

 cuts in the stem, yields nearly one-third of its weight of caoutchouc; 

 the collected sap is poured into boiling water and stirred till it 

 gets firm ; or the sap is poured into large bins partly filled with 

 water ; the fluid caoutchouc-mass after a while floats on the surface, 

 when it is taken out and boiled in iron-pans, after the addition of 

 two parts of water, the whole being stirred continuously ; after 

 coagulation the caoutchouc is taken out and pressed, and if 

 necessary boiled again, then dried, and finally washed with lime- 

 water. The sap from cuts into the branches is allowed to dry on 



