The 75 kilometres of open water between the Atures and Maipures Rapids is navigable for steamers during the greater part of the year, but the upper of the two great “raudales” proves a bar again to through communication with the upper Orinoco and its tributaries. Above Maipures, however, there is no serious hindrance to navigation, even through to the Amazon basin by way of the Casiquiare bifurcation.
CROSSING THE TORBES IN FLOOD.
Some twenty miles above Maipures the Orinoco receives the large volume of water drained by the River Vichada from the llanos of the San Martin territory of Colombia, and a little over one hundred miles from Maipures the Guaviare and Atabapo discharge their waters side by side into the main stream.
From the mouth of the Guaviare up to Esmeralda is probably the best known portion of the upper valley, since it is here that the majority of small rubber prospectors have obtained small fortunes after a short period of hard and rough labour in the insect-infested forests. The same causes as those referred to above in the lower parts of the Orinoco have here also prevented more systematic and continuous exploitation; those who have ventured to brave the discomforts and dangers of the forest have almost invariably retired with their gains to taste such pleasures of civilisation as the towns of the Lower Orinoco and neighbouring regions afford; thus the scanty population remains stationary, and previously, from want either of sufficient interest or opportunity, capital has never attempted to introduce colonists or to develop the resources of the region with such labour as can be had.
The picadores de goma have thus only seen the forests along the river for a few kilometres on either bank, and the remoter parts of the region are as little known as any other part of the territory of the Amazons. The rubber collectors enter the forest in the month of October, the season lasting from then to February or March, and parcel out the forest among themselves, each man taking an area including some five hundred trees or more. He then proceeds to cut an estrada through the forest along a tortuous course, so arranged that about half the rubber-trees lie on either side. He will begin to traverse this path at sunrise and tap the trees of either group on alternate days, the latex being carried back to the river late in the day and put to smoke in huts by the river. Each day he may collect eight or ten gallons of sap, and so twelve or fifteen hundredweight in the season, in addition to inferior gums derived from the creepers which hang everywhere from the large forest trees.
The rubber and other valuable trees, including the wild cacao and brazil-nuts, seem to become less scattered above Maipures, and this is doubtless an additional reason for the greater extent of exploitation in this more remote district, while it should also be remembered that the Casiquiare affords a highway for the bold and industrious Banibas and other Indians of the Rio Negro basin to the rubber-producing forests, which afford better returns than those in their immediate neighbourhood.
About forty miles above the mouth of the Guaviare, where the Orinoco again changes the direction of its course from parallel to meridian, the Delta and mouth of the great Ventuari tributary is encountered and beyond this the course is in a south-easterly direction and so continues as far as the source. The famous Casiquiare bifurcation is about 150 miles above the mouth of the Ventuari; and Esmeralda, the highest point of attempted permanent civilisation on the Orinoco, is some twenty miles beyond.
Esmeralda was, even in Humboldt’s time, a flourishing mission, but has been now for many years little more than a name, the houses being reduced to two or three huts. The name is derived from the quantity of fragments of chloritic and colourless quartz which lie scattered about the grass plains on which the mission was established. All travellers bear witness to the beauty of the position, with the peak of Duida visible beyond the forest to the north-east; but they also agree in considering Esmeralda the worst place for the tiny sandflies (mosquitoes of the Spaniards), which are the great plague of the Upper Orinoco.
Duida appears to be one of the peaks of the vertical-sided tableland type usual in Guayana, belonging to a range of mountains extending into the Piaroa territory, though broken at many points by river valleys, including that of the Ventuari. Though similarity of form cannot always be regarded as indicating identity of composition, the fact that such observations as have been made point to the floor of the whole elevated plateau of Guayana, here as elsewhere, being made of the same granite as that of the Roraima Hills and the Callao goldfields. It seems justifiable to suppose that all these peculiar mountains are of the same probably pre-Cambrian sediments, and it may be that Mount Duida and the range of which it is part will be found to be pierced by the dykes and sills which elsewhere in the Guayanas are often found to be accompanied by gold and other ores.