A GREAT SEA-WAVE. 221 



MQ. After passing far inland, the wave slowly re- 

 turned seaward, and strangely enough, the sea, which 

 elsewhere heaved and tossed for hours after the first 

 great wave had swept over it, here came soon to rest. 



At Callao a yet more singular instance was afford- 

 ed of the effect which circumstances may have upon 

 the motion of the sea after a great earthquake has dis- 

 turbed it. In former earthquakes Callao has suffered 

 terribly from the effects of the great sea-wave. In 

 fact, on two occasions the whole town has been de- 

 stroyed, and nearly all its inhabitants have been 

 drowned, through the inrush of precisely such waves 

 as flowed into the ports of Arica and Chala. But upon 

 this occasion the centre of subterranean disturbance 

 must have been so situated that either the wave was 

 diverted from Callao, or more probably two waves 

 reached Callao from different sources and at different 

 times, so that the two undulations partly counteracted 

 each other. Certain it is that, although the water 

 retreated strangely from the coast near Callao, inso- 

 much that a wide tract of the sea-bottom was un- 

 covered, there was no inrushing wave comparable with 

 those described above. The sea afterward rose and 

 fell in an irregular manner, a circumstance confirming 

 the supposition that the disturbance was caused by two 

 distinct oscillations. Six hours after the occurrence of 

 the earth-shock, the double oscillations seemed for a 

 while to have worked themselves into unison, for at 



