232 
In the Heart of Africa 
placed to the credit of the Congo State. Irumu, however, has 
to be content with an inferior position as regards the yield in 
rubber, on account of its distance from the forest’s edge. The 
monthly harvest amounts to only some 500 kilograms. This is 
an insignificant quantity when compared with that obtained in 
the main rubber centres—the Aruwimi and Uelle basins, Nepoko, 
Avakubi, Bomili, etc. There, during the best years, 7,000, 
10,000, and even 14,000 kilograms are produced monthly. Yet 
the rubber-tree plantations are exposed to special peril, as 
refractory natives lop and pull down the biggest and most 
valuable trunks of the Funtumia elastica and the gum-yielding 
liane. The insubordination of the population in the districts 
lying between the Aruwimi and the Uelle assumed previously 
such a threatening character that a punitive military force was 
despatched there. The Chef de zone, resolute and trustworthy 
Commandant Engh, a Norwegian by birth, had to proceed to 
the scene to restore order; and through his own wariness and 
discretion, as well as that of his officials, this was eventually 
accomplished. 
Rightly recognising the danger that threatened the rubber 
industry in consequence of the hostile attitude of the natives, 
the Congo State has for some years established great rubber 
plantations ; in fact, we came across them at all the more import¬ 
ant European stations. The plantations, however, being only of 
recent growth, it has so far not been possible to determine 
decisively which sorts are most suitable for cultivation. 
The nature of the ground has been taken into account 
generally, and those varieties selected which flourish best under 
similar conditions in the virgin forest. Commonly, ih.^ Funtumia 
elastica is given the preference, as it grows much more rapidly 
than the rubber vine. Whilst the tree can be tapped, without 
injury to its growth, after a period of six or seven years, the vine 
can only be turned to account after twenty years. The cultivation 
of the liane, therefore, is on the decline, and they are only grown 
where the funtumia will not flourish. 
At all European stations one plant must be put in the ground 
