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per man should the estate be already overworked. As each man 

 works 200 trees, this would place the yield of one tree, when 

 worked under satisfactory conditions at j to ij kilos, per annum. 

 On the same basis and taking the whole of the crop from the 

 Amazon district as being 24,000 tons (about) per annum there 

 would appear to be about 120,000 labourers employed in cutting 

 rubber at present. Calculating still on the same basis there should 

 be some 24,000,000 trees being tapped, and these on a basis of one 

 tree to every 2 acres would give an area of about 50,000,000 acres 

 of forest at present being worked for rubber. When it is con- 

 sidered that the district in question embraces well over 1,000,000 

 square miles, and that it is by no means easy to find virgin rubber 

 forest within 200 or 300 miles of Para or Manaos, it will be seen 

 how comparatively scarce is the Hevea, in the Amazonian forests. 



The Hevea, is found to yield its latex more freely at the base than 

 higher up the trunk. In some places, however, where the trees 

 have already been considerably worked, and the lower part of the 

 trunk is already covered with knobs due to excessive tapping, it is 

 the custom to build stagings in order to enable the rubber cutters 

 to reach a higher portion of the trunk. A good tree will still yield 

 freely to a height of some 20 or 30 feet. 



If allowed to rest for three or four years, even a completely ex- 

 hausted tree will quite recover itself, and may be worked again 

 from the base. As has been already stated, the tree is not killed 

 when the supply of latex runs short, and as a rule sufficient dam- 

 age has not been inflicted to prevent the tree from recovering it- 

 self. This fact is important, as owing to it the supply of rubber 

 available will probably not run short as has been often prophesied 

 of late. Trees have been known to have been lapped off and on 

 during 50 years, and to be still yielding a plentiful supply of latex. 



The latex having been obtained and collected the 4< caoutchouc," 

 or rubber known to commerce, may be obtained from it in various 

 ways. The onlv method, however, that has met with practical 

 success is that of eva poration, by which the watery portion of the 

 latex is driven off and solid caoutchouc remains. The object to be 

 secured is that as little water and proteid matter shall remain in 

 the caoutchouc, the putrefaction of the caoutchouc, owing to the 

 presence of these matters being extremely detrimental to its elas- 

 tic properties, and, therefore, to its market value. In the Amazon 

 district the method followed is to light a fire upon the ground and 

 to invert over it a specially constructed funnel-shaped-chimney. 

 From the narrow end of the funnel, which is open, the smoke and 

 heated gases pour out in a concentrated form. The fuel used for 

 the fire consists, as a rule, of chips from any hardwood tree that 

 grows handy to the labourer's hut. The nuts of the " Urucury 

 palm " {Attalea excelsa) are sometimes used, their smoke contain- 

 ing a trace of acetic acid and creosote being found particularly 

 effective in curing the rubber and preventing putrefaction. It is, 

 however, a mistake to suppose that all or even a large proportion 

 of the rubber coming from the Amazon district is cured in this way. 

 It is, on the contrary, very rarely that the rubber-cutter will be at 



