206 LIGHT SCIENCE FOR LEISURE HOURS. 



More complete details reach us from the Southern 

 Pacific. 



Shortly before midnight the Marquesas Isles and 

 the low-lying Tuamotu group were visited by the 

 great wave, and some of these islands were completely 

 submerged by it. The lonely Opara Isle, where the 

 steamers which run between Panama and New Zealand 

 have their coaling station, was visited at about half-past 

 eleven in the evening by a billow which swept away 

 a portion of the coal depot. Afterwards great waves 

 came rolling in at intervals of about twenty minutes, 

 and several days elapsed before the sea resumed its 

 ordinary ebb and flow. 



It was not until about half-past two on the morning 

 of August 14, that the Samoa Isles (sometimes called 

 the Navigator Islands) were visited by the great wave. 

 The watchmen startled the inhabitants from their 

 sleep by the cry that the sea was about to overwhelm 

 them ; and already, when the terrified people rushed 

 from their houses, the sea was found to have risen far 

 above the highest watermark. But it presently began 

 to sink again, and then commenced a series of oscilla- 

 tions, which lasted for several days and were of a very 

 remarkable nature. Once in every quarter of an hour 

 the sea rose and fell, but it was noticed that it rose 

 twice as rapidly as it sank. This peculiarity is well 

 worth remarking. The eminent physicist Mallet 

 speaks thus (I follow Ly ell's quotation) about the 

 waves which traverse an open sea : The great sea- 

 advancing at the rate of several miles in a 



