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tiiid (lowiiwiird direction. The spi-iiiLï luis coiiscqiieiidv ;i \cry cX^eeiitric' 

 situjilioH ill the luiidtiold lluil luis heen forined hy il. It was elearly 

 visible on llie spot lluil towards the higliei' side a biji; pieee ot 

 gToiiiid liad been i-eino\ed by Wic brcakin.g-oiil of the solfatare ; 

 now it is reniarkable that we found the (diasni separated from the 

 adjacent Pentoe-bed by a narrow strip ol' niidisliirbed gronnd, only 

 iiilerrnpted by the channel evidently cni in by the escaping mnd- 

 water, whilst it niiglit have been ex[)ecled thai the great hydranlic 

 |»ressnre wonld luive had I he greatest etl'ecl towards the weakest 

 side i. e. towards the bed ol' the brook. l>oth phenomena can, in my 

 0|)inion only be explained, if we admit that the lirsl l)reak-ont was 

 not vertical bnt in a diagonal and upward direction, away from the 

 Pentoe, tending nearl}' towards the Sopoelan-axis. 



I fonnd the last-mentioned peculiarity likewise at the Roemercga. 

 This spring is situated to the right of the Pentoe, here ali-eady a 

 rather strong though still small mountain-stream, only a few meters 

 apart from the bed of the brook, at the h)ol of a wall showing 

 the ravinaled super})Osition of the bhudv Sopoelan sand on the greyisli 

 tul'aceous material. The bottom of the hole, enclosed by that wall 

 and ihc little dam at the side of the bi-ook, is covered with luke- 

 warm clear water, which ag;iin has ils oul-llow lo I he brook on 

 ihe downwai'd side. <)f suppiy-orilices nothing was to be seen. 



About 40 M. ahead, nearly one kilometer below the new solfalare, 

 the mnd-stream still formed a se|»arale central \ein with a tem|)eratui-e 

 of ± 70° in the here about i\/^ M. wide and 0,1 AI. deep wal(M-- 

 bed of the Pentoe. That as yd no mixtiiiv had taken place may 

 be considered, in my ()j»ionion, as another indication of Ihe \iscosily 

 of the mud, resulting again from the presumed jtreseuce of colloïdal 

 free silica. The presence of sulphurelled hydrogen could be ascertained 

 in the mud and also by the smell in the atmosphere. On cIiIkm' 

 side of ihe bed there w^as a fringe about 1 M. wide of the sofi, 

 grey mud, apparently dating from former stronger jteriods in the 

 efllux, when the stream of mud may have tilled the whole bed. 



Even on the edge of the new chasm, notw iihsianding the violent 

 boiling inside, we could not obser\e any spirting of the mud. This 

 must have occurred during still mov(^ itowerful initial activity, which 

 in the very i)eginning must have shown a paroxysmal character. 

 This hardly 5 cM thick sheet of mud wonld certainly not have 

 stood against siudi tremendous rains as one can only enjoy on the 

 mountains in our tiopical archipelago-climale, during the couple 

 of weeks that had elapsed at the time of our visit, since the forma- 

 tion of the spring. 1 Ihink this entities me to conclude that such 



