IN BORNEAN FORESTS [chap. 



As soon as the head-man of Lamadjan, Rading Sira (the title 

 indicates a Javanese origin), heard of my arrival, he invited me 

 to go up to his house and offered me siri, politely insisting that I 

 should stay in his village. Although this is built on an island, 

 there was then not a foot of dry ground around it. The water was 

 nearly on a level with the flooring of the houses. Every year 

 during the rainy season the water rises a good deal on the lakes, 

 "but very rarely as high as its then level. Some trees only showed 

 their tops above water, whilst quite a number of shrubs could be 

 seen beneath the keel of our boat. 



The people at Lamadjan assured me that the waters of the 

 lake always have the black colour which had struck me so much, 

 and are never turbid. Intika, my guide, asserted that there are 

 about thirty lakes like that of Lamadjan, and amongst the prin- 

 cipal ones he mentioned Danau Malayu (or Malau ?), D. T'kanan, 

 D. Bekuan, D. Pandan, D. Bulumbong, D. Gamali. I have an idea 

 that these lakes are for the most part surrounded not by raised land, 

 but by forest, which I would describe by the term " palustral," 

 the soil of which would be dry only occasionally, in periods of 

 great drought, when the waters are at their very lowest. 



The lacustrine region, as a whole, must be of wide extent, but 

 the water surface free from trees is, perhaps, never more than five 

 or six miles in length. The natives of Lamadjan asserted that in 

 very dry seasons some of these lakes dry up, leaving a prodigious 

 quantity of fish exposed or densely packed in small pools, where 

 they can be caught by hand. They also assured me that there 

 is no mud on the bottom, which is not surprising, being a natural 

 consequence of the absence of earthy deposits in the water. If in 

 times of flood such as we experienced the water remained perfectly 

 clear, it is evident that it can never be other than in that condition. 

 It would be highly interesting to examine the bottom of these 

 black-water lakes when dry in order to investigate the nature of 

 the deposits. These, I should think, must be entirely of vegetable 

 origin, without any admixture of earthy elements. It would also 

 be instructive to ascertain the results of thoroughly drying them — 

 to learn, in short, whether the great quantity of substances derived 

 from the humus (rich, it should be remembered, in carbon) and 

 held in solution by the black waters can, through the evaporation 

 •of their solvent, contribute to augment the mass of carbonates 

 on the bottom of the lake basins, and also whether any special 

 chemical reaction occurs to aid such augmentation. 



Considering the great mass of organic substances in decomposi- 

 tion which continually accumulates in the forest, it is presumable 

 that the flood waters dissolve not only the acids derived from the 

 carbohydrates, but also various other substances which, under 

 certain conditions, may originate insoluble deposits of a black 



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