981 



grow lip. The objection that a result from this experiment cannot 

 be obtained before a hundred jears later, cannot be a reason for 

 not trying it now. It should be attended, however, with a second 

 experiment, viz. of planting seedlings of other djati-varieties on a 

 patch of lime- or marlgroiinds, in order to ascertain whether stems 

 of djati-kapur may be grown from them '). 



Lastly the question may be asked : what is tiie fate of the |)hos- 

 phates secreted in tiie stems of djati. kapuv? The stems, the branches 

 and the leaves rotting in the forests retui-n in the compounds of 

 phosphorus present in the tissue, to the gi-ound in the form of wood 

 ashes. In this process the concretions also must come to the same 

 place, though it has not been recorded anywhere that they were 

 found there. 



A regular forest-administration will cause them to be tiansported 

 elsewhere together with the stems in which they are shut up. It is 

 obvious, therefore that the quantity of conci-etious remaining on the 

 forestgrounds cannot be very large. Moreover most of them are of 

 small dimensions and very soft, so that they readily fall to pieces 

 and will be transpoi'ted farther in the wet season, so that only 

 very few will be left behind. The inevitable decomposition-process 

 is much slower of course, since though it may be ti-ue that calcium- 

 phosphate is assimilated by the root of the plant, atmospheric intlu- 

 ences aflfect it in a much smaller degree, than is the case even with 

 a number of silicates. I, therefore, deem it very probable that the 

 numerous kidnej'-sliaped concretions, found neai- Solo in the territory 

 of Surakarta in the clay oveilying the tertiary sediments, may be looked 

 upon as a remnant of the secretions formed in the djati kapiir, as 

 assumed by R. D. M. Verbeek *). An analysis by J. G. Kramers 

 led to the following results: «^ 



SiO' .... 8.81 



P'O^ .... — 



CO' . . 

 Fe*0' + APO' . . 



CaO . . 



H*0 . . 



98.32 



1) H. TEN Oevee (Gordes: De Djatibosschen op Java, Boschbouwk. Tijdschr. 

 Tectona 9. 1916. Batavia 1917, p. 869) lias already pointed out thai only a 

 thorough investigation of the so-called djati-varielies with respect to their being 

 true to seed will enable us to settle this question. 



^) R. D. M. Vkrbeek en R. Fennema. Geologische beschrijving van Java en 

 Madoera 1. Amsterdam 1896, p. 209, 325. 



