( 409 ) 



phciioineiiji of ll)()l. The iK\u;i(i\o fju't lluil liiis iin|)()'^iii,L>- uiid not 

 at all e.xtiiH'l looking- cralor '), rciiiaiiKMJ (Miliivly passix'e (liii'iiii>' ;tll 

 llie volcanic phenomena tiiat look ])lacc at ils fooi is perhaps no 

 less i-eniarkahle than the series of positive facts themselves, andean 

 btit confirm our opinion that the veal canse of the recent activity, 

 (lie magma-hearth, ))resumable in itsell" alreadv not |)rimarv, '^^ 

 seated at shallow depth. It is not less remarkable that, whilst on 

 acconnt of the topographical sitnation might be said that the old 

 Rindengan-volcano has resumed its activity, the emerged material, 

 as has already been said, seems to cori-espond petrographically to 

 that of the eruptions of Sopoetan pi'opei-. 



Now it is (piite natural that we should ti-y to lind a co-relation 

 between the phenomena of 1901 and those of 190(V1909. l>ut the 

 nature of this co-i-elation is not so easil>' detected and al all e\en1s 

 not so, that the former of necessity should have been directly 

 precursory to the latter; therefor the occurrences were eacli time 

 too much localized, to spots that for the two cases are 600 M. apart. 

 We might account for the connection in the following way: About 

 or in 1901 |)art ol" the magma |)enetraied by way of apophysis into 

 the humid zone, — the real character of which may remain undis- 

 cussed here, — and by local i]icalesceuce caused the bursting foi-lh 

 of the solfatare. The magma on the other hand cooled gradually 

 down, contracted and left free space which atforded to a new 

 supply of magma about 1909 the oi)portunity of congealing under 

 reduced pressure. This laller iiiitially quickly progressing process, 

 caused the eruptive formation of the crater-cone 4, through which 

 at the further |)rogress the formed cinder-material, in consequence 

 of the increase in volume, contiiiued (o move to the outside. So a 

 new fact, the posterior afflux of jnagma, was necessary to cause the 

 phenomena of 1901, after some years of continual cooling dowMi 

 and contraction, to be followed l»y the oiitbivak ol' 1906, and what 

 was further coniiecled with it. A similar co-relation might perhaps 

 be established bclween the solfatare Walelang and the ei'uptive 

 mound within I he old Sempoe-crater and between lloemcrcga and 



1) I cannot fully ;ulniil i\h'. AnLBUiUi's view (I.e. p. 1!)8 ami üüü), that the 

 hotloni of the eraler sliouKl liave risen IVom UJii<nown (.ieplh to "200 and 100 M. 

 heneiitli the edge since llie eiuplion of 1838C::') by the crumbling down of the 

 walls, in 1899 and 1901 1 was able, like Mr. A. in 190i>, to see al (lie loo! ct 

 the guaf the in my "pinion evidently original bnttom willi its boccas at tlie 

 southside, wherever the '"lioirur vacni'" and the prolile ol' the eralcrwall did not 

 prevent me from looking down. It seems to nie lliat Rinne'.s clause to which A. 

 refers, quoted also by VVichmann in his crilieal notice (I.e. page 59;}), does not 

 mean what A. has apparently read in it. 



