182 IN THE WILDS OF SOUTH AMERICA 



their leafy crowns far above the mere rabble of palms and 

 lower growth, shutting out the light and effectively killing 

 their competitors until after hundreds of years of suc- 

 cessful fighting the strain begins to tell and the monarchs 

 are compelled to bow before the inevitable onslaught of 

 old age. At the first signs of weakness enemies spring up 

 on every side. The struggle for life is constant and in deadly 

 earnest. Of the hundreds, perhaps thousands, of saplings 

 which appear as the light and air gradually penetrate through 

 the opening made by the dying giant, only one can even- 

 tually survive. Naturally, the strongest and fittest pos- 

 sesses every advantage in the mad fight for existence, and 

 as it quickly outstrips its weaker rivals they wither and 

 die. 



The launch called at a number of rubber-plantations 

 and lumber-camps. Great quantities of greenheart (Nec- 

 tandra rodicei) are cut and exported; the wood is very hard 

 and durable, and resists decay when under water, for which 

 reason it is used largely for submerged work such as wharfs 

 and piles. Next in importance is crab-wood (Carapa guia- 

 nensis) employed in building houses; third in value are 

 several varieties of wallaba (Eperud) ; this wood has a coarse 

 but even grain and is very resinous, being suitable for the 

 manufacture of shingles and vat-staves. 



The rubber industry ranks third in importance in British 

 Guiana. By far the greater part of this product is balata, 

 collected from indigenous trees that are tapped under care- 

 ful government supervision. Sapium yields the better qual- 

 ity of rubber, but exists in limited quantities only, and the 

 majority of the trees on plantations have not yet reached 

 the productive age. 



Our first headquarters were made at Tumatumari, a 

 short distance above the mouth of the Potaro River. The 

 river is at this point encumbered with a series of rapids 

 ending in a fall of twenty or thirty feet. 



Tumatumari is a small negro settlement, and owes its 

 existence to the gold-mines scattered throughout the sur- 



