THE PRINCIPAL RUBBER DISTRICTS 27 



such expeditions were sent from the Pacific slope for 

 that purpose ; but that system has long disappeared, 

 and to-day practically all the rubber is obtained by the 

 employes of permanent establishments working regu- 

 larly within the circumscribed areas of their respective 

 concessions. The only variation from this rule is in 

 the case of certain districts where small gangs of men 

 obtain permission to collect caucho or castilloa, and even 

 when this occurs stringent conditions are exacted as to 

 the terms under which the work shall be done, and the 

 subsequent delivery of the product to the owners of the 

 property exploited. 



For descriptive purposes, the rubber-producing dis- 

 tricts of the Amazon Valley may be divided into three 

 sections, and in each of these the methods employed 

 differ in many practices. The first section comprises 

 the delta of the Amazon, the numerous islands situated 

 in the river, and the tributaries discharging into the 

 main stream for a distance of some 500 miles from its 

 junction with the Atlantic; the second area is the 

 territory stretching eastwards from the vicinity of 

 Santarem, and including the neighbourhood of Manaos, 

 the Madeira, the lower portions of the Rivers Purus and 

 Jurua, a part of the Rio Negro, and many other water- 

 ways ; the third section takes in the rubber districts of 

 Bolivia, the upper rivers, and the country included 

 within the boundaries of Peru, Ecuador, and as far 

 north as Colombia. 



On the islands in the Amazon delta the land is low- 

 lying and subject to the effect of ocean tides. At high- 

 water the ground is inundated over a very large propor- 

 tion of the area where rubber-trees are found within 



