Related Geological Conditions 45 



is recorded that after the rain of pumice stone in the early 

 morning, only dust and water fell in the form of mud, which 

 accumulated on deck at the rate of six inches in ten minutes. 



But it is observed that the discharge was probably much 

 less than that from other volcanoes in historic times, for 

 that "of 1783, and of Tomboro, in Sumbawa in 18 15, were 

 all accompanied by the extrusion of much larger quantities 

 of material than that thrown out of Krakatoa in i883«" 



As to the total quantity of dust ejected, and the distance 

 to which this was carried, the results unfortunately from 

 the geological standpoint are meagre and conflicting. From 

 the reports of persons on board vessels in various parts 

 of the ocean, and from those of persons at various points of 

 land Verbeek has reached conclusions of approximate value. 

 But Archibald {21; 448) comments thus on these: "If 

 we suppose that the area represented by these ships alone" 

 (dealt with in the report) "was 1,100,000 sq. miles, and 

 was covered uniformly to a depth of only 5 millimeters or 

 0.02 inch with dust, we should find for the total amount 

 which thus fell 14.4 cubic kilometres (3^ cubic miles) an 

 amount not much less than that calculated by Mr. Verbeek 

 for the total amount of materials of all kinds ejected. It 

 appears then that the finer dust, which was transported 

 to more than 2000 English miles from the volcano toward 

 the west alone, might have equalled in amount what fell in 

 its immediate vicinity; and it seems quite possible that as 

 large or even larger a quantity was blown into such minute 

 particles as to be capable of remaining in the highest regions 

 of the atmosphere, and being carried right around the world 

 in the tropical zone within a few days after the eruption." 



From the mineralogical, the geological, and not least 

 for our present purpose from the palaeontological stand- 

 points, some comparative analyses made by Retgers at the 

 Buitenzorg station are highly suggestive, as are the com- 

 ments by Judd on these. He separated the glassy or 

 vitreous particles from the crystalline, and also the several 

 mineralogical varieties of the latter — the felspar, the en- 

 statite, the augite and the magnetite — from each other, 

 with the following results: 



