( 234 ) 



paroxystïuil increase of ju'liA'itv must liavc repeatedly occurred. It 

 may indeed be expected that with sucli newly funned springs a 

 state of permanent equilibrium ensues only after a pei-haps rather 

 long lapse of time. It .seems even that the Walèlang, dating from 

 before 1821^), was not yet in a state of regidarized activity when 

 it was visited by 1vIN>k in 1899. This is perha|>s the cause that the 

 desci-iptions of its appeai-ance are greatly at xariance. Even now 

 this solfatare had not yet (|uieted doun. We obser\ed some bui)bling 

 near the north-east coiJier and now and then in a little round 

 pud<lle in the half dried u|> western j»arl on the sulphur-crusted 

 land-tongnes. 



Notwithstanding the apparent contrast between the minute boiling 

 chasm of 1901, the com|)aratively gently steaming but 300 by IGO M. 

 measuring lake of Walelang and the lukewarm pool of Roenrr ga 

 the dilferences are in my opinion rather of a gradual nature with 

 regard to si/e as well as to intensity. Numerous more or less radiat- 

 ing rents at the foot of the Kctengen-wall, in \vhich the white under- 

 gi'oiind and some sulphui- was visible, and which gave some idea 

 of the great subterranean pressure that has caused the eruption of 

 the mud-stream, in the mean-lime enforced the im|>ressiou thai with 

 undiminished power the chasm would enlarge itself still considerably 

 also towards tliis side. 



These crevices must be well distinguished from the long, narrow 

 crevices, ahnost hair-iissurcs, observed in the gravel-field to the south 

 of our Sem|)oe, and on the top of the Sopoetan-cone from the crater- 

 edge to about fifteen meters down along the northern and north- 

 eastern slopes. Here they follow pretty well the Jevel lines. The 

 vapours constantly issueing from this highest part of the volcano- 

 mantle, now mostly rose from these crevices, which did not exist at 

 the time of my former visit. South of Sempoe the direction of the 

 crevices was about N. 40° East. In my opinion they are of seismic 

 origin and as such likewise known from other places. The pretty 

 compact coarse sand has sufficient coherence to prevent these traces 

 of the effects of the earth([uakes from disappearing again immediately 

 after the shocks. Fresh landslii)s in the Sopoetaji-crater proved that 

 the loosening of the mass of the edge along concentrically running 

 lines had gone a little further. Such slips of band-shaped, concentric 

 masses from the upper edge inside the crater are not restricted to 

 the latest earth-quake-period ; they have also been observed by the 

 Sarasins (1. c. p. 60) ; and have left at the north-eastern wall in a 



') Mentioned by Reinwardt, wlio visited this solfatare in 1821. 



