could only wait a few days at the island, a time quite insufficient 

 for a close botanical investigation. For many years already the 

 Laboratory for Marine Investigations at Batavia (ressorting under the 

 Botanical Institute of Buitenzorg) has disposed of a steam-ship on 

 behalf of the voyages of the officials of that laboratory, but trips 

 to Krakatao are so very costly that, when not necessary for the 

 service, they can but seldom be made. 



Other difficulties arise from the nature of the island. This is 

 about 14 km-, in size and strongly accidented, with the exception 

 of a few level beaches. Krakatao, by its large size already rather 

 unsuitable for a minute investigation, is ploughed in all directions 

 by innumerable deep (down to 40 m.) and very precipitous ravines 

 which at every moment hinder or arrest the penetration of the island; 

 the investigation is made still more difficult by the locally often very 

 dense, almost impenetrable vegetation, by the humid heat and by 

 hosts of most aggressive ants and mosquitoes. There is, at the sur- 

 face at least, no water, there is no living man, hence neither food 

 nor coolies are available. Without coolies an extensive botanical 

 investigation in very accidented localities in the tropics cannot pos- 

 sibly be carried out. Researches satisfying moderate scientific claims 

 would be of many weeks' duration and should be often reiterated 

 and therefore would be very expensive. 



This juncture of unfavourable circumstances is the principal cause 

 why until now botanical investigations were only made in few and 

 comparatively restricted areas of the is/and and often with long inter- 

 vals, sometimes of 10 years and longer, and also why these investi- 

 gations always were most superficial. An exploration satisfactory to 

 scientific demands was never yet made. 



The long intervals between the successive investigations and the 

 fragmentary and most superficial character of these have caused 

 that we do not know with sufficient accuracy how the vegetation 

 of Krakatao was composed in the first decennia after the eruption, 

 which period was the most important one for the investigations. 

 For in the tropics also, the flora shows the phenomenon that in a 

 not too restricted locality, that may be considered as an oecological 

 unity, besides some dominant or constant species there always are 

 accessory ones. Of this fact junghuhn" 1 ) already gave an instance 

 (Exacumj in his description of the alang-fields. The phenomenon is 

 best to be observed in localities where a state of equilibrium has not 

 l ) | u n g h u h n, |ava, Second Dutch Ed- I, 291; German Ed. I, 213. 



