While the ashes of the wood contained
0.0612 of the whole weight of the wood, the pith was found to contain
0.448 per cent., the inner wood much less, and the greatest proportion
occurred in the external wood. On these determinations Guibourt founded a
theory of the mode of formation of tabasheer based on the suggestion that
at certain periods of its growth the bamboo needed less silica than at
other times, and that when not needed, the silica was carried inward and
deposited in the interior.
In the year 1857, D.W. Host van Tonningen, of Buitenzorg, undertook an
investigation of the tabasheer of Java, which is known to the natives of
that island under the name of "singkara" (_Naturkundig Tijdschrift voor
Nederlandsch Indie_, vol. xiii., 1857, p. 391). The specimens examined
were obtained from the _Bambusa apus_, growing in the Residency of
Bantam. It is described as resembling in appearance the Indian
tabasheers. Its analysis gave the following result:
Silica. = 86.387
Iron oxide. = 0.424
Lime. = 0.244
Potash. = 4.806
Organic matter. = 0.507
Water. = 7.632
------
Total. 100.000
Apart from the question of its singular mode of origin, however, and its
remarkable and anomalous physical properties, tabasheer is of much
interest to mineralogists and geologists.
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