A MIGHTY SEA- WAVE. 189 



the Atlantic. The direct wave would have come sooner, 

 and may have escaped notice because arriving in the night- 

 time, as it would necessarily have done if a wave which 

 travelled to California, and thence, after reflection, to the 

 Sandwich group arrived there at a quarter before five in the 

 morning following the Peruvian earthquake. We shall be 

 better able to form an opinion on this point after considering 

 what happened in August, 1868. 



The earth-throe on that occasion was felt in Peru about 

 five minutes past five on the evening of August 13. Twelve 

 hours later, or shortly before midnight, August 13, Sandwich 

 Island time (corresponding to 5 p.m., August 14, Peruvian 

 time), the sea round the group of the Sandwich Isles rose in 

 a surprising manner, " insomuch that many thought the 

 islands were sinking, and would shortly subside altogether 

 beneath the waves. Some of the smaller islands were for a 

 time completely submerged. Before long, however, the sea 

 fell again, and as it did so the observers found it impossible 

 to resist the impression that the islands were rising bodily 

 out of the water. For no less than three days this strange 

 oscillation of the sea continued to be experienced, the most 

 remarkable ebbs and floods being noticed at Honolulu, on 

 the island of Woahoo." 



The distance between Honolulu and Arica is about 6300 

 statute miles ; so that, if the wave travelled directly from the 

 shores of Peru to the Sandwich Isles, it must have advanced 

 at an average rate of about 525 miles an hour (about 450 

 knots an hour). This is nearly half the rate at which the 

 earth's surface near the equator is carried round by the 

 earth's rotation, or is about the rate at which parts in latitude 

 62 or 63 degrees north are carried round by rotation; so 

 that the motion of the great wave in 1868 was fairly com- 

 parable with one of the movements which we are accustomed 

 to regard as cosmical. I shall presently have something 

 more to say on this point. 



Now in May, 1876, as we have seen, the wave reached 

 Hawaii at about a quarter to five in the morning, correspond- 



