A GREAT SEA-WAVE. 2OI 



be seen at once that within this region, or rather 

 along that portion of the sea-coast which falls within 

 the central region of disturbance, the true character of 

 the sea-wave generated by the earthquake could not 

 be recognised. If a rock fall from a lofty cliff into a 

 comparatively shallow sea, the water around the place 

 where the rock has fallen is disturbed in an irregular 

 manner. The sea seems at one place to leap up and 

 down ; elsewhere one wave seems to beat against 

 another, and the sharpest eye can detect no law in the 

 motion of the seething waters. But presently, outside 

 the scene of disturbance, a circular wave is seen to 

 form, and if the motion of this wave be watched, it is 

 seen to present the most striking contrast to the 

 turmoil and confusion at its centre. It sweeps onwards 

 and outwards in a regular undulation. Gradually it 

 loses its circular figure (unless the sea-bottom happens 

 to be unusually level), showing that although its 

 motion is everywhere regular, it is not everywhere 

 equally swift. A wave of this sort, though incom- 

 parably vaster, swept swiftly away on every side fronv 

 the scene of the great earthquake near the Peruvian 

 Andes. It has been calculated that the width of 

 this wave varied from one million to five million feet, 

 or roughly, from 200 to 1,000 miles, while, when in 

 mid-Pacific, the length of the wave, measured along 

 its summit in a widely-curved path from one side to 

 another of the great ocean, cannot have been less than 

 8,000 miles. 



We cannot tell how deep-seated was the centre of 



