THOUGHTS ABOUT KRAKATOA. 331 



that the waves had, of course, to cross the poles in their 

 journeys, it would almost seem that within the limits of 

 probable error the speed of the great wave and the speed of 

 ordinary sound waves were identical. It would, I think, 

 have been an improvement on the plates containing the 

 barograms, if the scale had been given, so that it would 

 have been possible to obtain some definite notion of the 

 amplitudes of the oscillations at the different stations. 

 The only pressure-diagram contained in the plates which 

 does give any scale measures, is that of the gasholder at 

 Batavia ; from this it would appear that the barometric 

 fluctuation produced by the great wave was about four- 

 tenths of an inch of mercury at a distance of 100 miles 

 from the source of disturbance. 



While the chapter on the air- waves is the most novel 

 scientific feature in the Report of the Krakatoa Com- 

 mittee, it will be admitted that the most amazing features 

 of the same work are those contained in the section on 

 " Sounds." Here we find a collection of statements so 

 marvellous that they would be well-nigh incredible were 

 it not for the ample body of excellent testimony by which 

 they are substantiated. In the whole annals of noise 

 there is nothing which can be compared to the records 

 set forth in a table which occupies not less than eight 

 pages of the volume. (See Fig. 19.) Let us select a few 

 instances, almost at random. 



Lloyd's agent at Batavia, 94 miles distant, says that 

 on the morning of the 27th of August the reports and 

 concussions were simply deafening. At Carimon, Java 

 Island, reports were heard which led to the belief that 

 some vessel offshore was making signals of distress, and 



