334 IN STARRY REALMS. 



tinuous chain of evidence from places at gradually increas- 

 ing distances from Krakatoa, we might well hesitate to 

 believe that the noises Mr. Wallis heard were really from 

 the great volcano, but a glance at the map, which shows 

 the several stations where the great sounds were heard, 

 leaves no room for doubt. We have thus the astounding 

 fact that almost across the whole wide extent of the 

 Indian Ocean, that is, to a distance of nearly 3000 miles 

 (2968), the sound of the throes of Krakatoa was pro- 

 pagated. 



We appreciate this result more strikingly if we reflect 

 on the velocity of sound. Seconds or minutes may elapse 

 between the appearance of a flash of lightning and the 

 arrival of the thunder. But the volcanic sounds could not 

 have been heard at Rodriguez until four hours after they 

 had commenced to travel from Krakatoa. Were Vesuvius 

 now to break out as Krakatoa has done, every inhabitant 

 of Great Britain would apparently be quite near enough 

 to hear the awful detonation. 



I shall content myself with the mention of three facts 

 in illustration of the great sea waves which accompanied 

 the eruption of Krakatoa. Of these, probably the most 

 unusual is the magnitude of the area over which the 

 undulations were perceived. Thus, to mention but a 

 single instance, and that not by any means an extreme 

 one, we find that the tide gauge at Table Bay reveals 

 waves which, notwithstanding that they have travelled 

 5100 miles from Krakatoa, have still a range of eighteen 

 inches when they arrive at the southern coast of Africa. 

 The second fact that I mention illustrates the magnitude 

 of the seismic waves by the extraordinary inundations 



