25 



ably several of these factors have co-operated to destroy the super- 

 terranean vegetation almost completely. 



But all this proves by no means that everywhere the soil was 

 heated so much and to such a depth that all subterranean parts of 

 the vegetation were killed. In the higher regions the underground was 

 protected against being heated too much by the comparatively cold 

 ashes and fine grit which continually fell down- The large blocks, glow- 

 ing hot within, but already somewhat cooled on the outside, did 

 not remain above but rolled and leapt rapidly down till they reached 

 the lower parts. There only they can have strongly heated the soil 1); 

 on the higher parts of the cone they did not remain long enough 

 to do so. For pumice and ashes are very slow conductors of heat, 

 and heat does not soon penetrate deep into the soil as may be obs- 

 erved everywhere. After every forest-fire it appears that the flames, 

 though having destroyed many or all superterranean organs and having 

 more or less deeply carbonized the trunks of the trees, have not 

 entirely killed the vegetation. A number of plants always survive by 

 their subterranean organs and, some time after the fire, everywhere 

 young growth appears from roots, rhizomes or seeds, that have re- 

 mained in life. On May 23rd 1901 Mount Kelut ejected glowing hot 

 vapor-blasts and ashes that killed several people and locally scorched 

 the superterranean vegetation. Vorderman, when visiting a week 

 afterwards the spot where the calamity had occurred, observed -) 

 that a scorched specimen of Amomum then already was forming 

 new leaves, which shows that the heat cannot have penetrated deep 

 into the soil. 



During several hours on the last day of the eruption (Aug. 27th 

 1883) a drizzling rain of cold humid ashes fell in West-Java and South- 

 Sumatra 3 ) and caused a considerable reduction of the temperature '). 

 On the interjacent island Krakatao most probably the same has 

 happened. If so, this cold rain will have contributed to reduce the 

 temperature of the fallen materials. Wherever the covering layer was 

 thin, the temperature of it must have fallen perceptibly. 



Taking all this into consideration I cannot admit that from the 



!) A few days after the enjptjpn of Mount Kelut in 1919 Kemmerling (Vul- 

 kanol. Meded. II (1921), pp. 77, 78) observed in and near the crater in a loose mass 

 of pumice, washed together by a flood of water, temperatures of + 200 C and a 

 fortnight afterwards yet of 165 C. 



2 ) Teysmannia XII (1902), p . 270. 



*) V e r b e e k, Krakatau, Dutch Edition (1888), pp . 45, 51, 96, _ French Edition 

 (1885) pp. 47, 58, 100. 



4 ) V e r b e e k, Krakatau, Dutch Edition II (1885), 324. 



