50 THE OCEAK 



CHAPTER YI. 



WAVES OF THE SEA. — REGULAR AND IRREGULAR UNDULATIONS.— HEIGHT OF 

 THE WAVES. — THEIR SIZE AND SPEED. — GROUND-SWELL. — COAST-WAVES. 



The sea rarely presents a glassy surface. "When tlie atmosphere is 

 calm, which however is commonly the case before a tempest, the 

 •water is sometimes so very smooth that every object is reflected by it 

 with a perfectly sharp outline ; the only changes which seem to affect 

 the vast motionless sheet of water are those produced by the mirage, 

 which makes the distant horizon glitter like a long band of silver or 

 steel ; the fishermen then say that '' the sea is reflecting itself." 

 But this tranquillity of the water is a very uncommon phenomenon, 

 except in the Mediterranean and other seas, where there is only a 

 slight tide. Usually the wind, either in breezes or tempests, now 

 aiding and now retarding the ebb and flow, raises the sea into 

 waves, more or less high, which sometimes roll onward regularly, 

 or are dashed against and cross one another. Even during calms, 

 the weaves, still obeying the impulse of recent winds, continue 

 to roll across the ocean in long undulations. One of the grand- 

 est spectacles at sea is offered by these regular movements of the 

 waves in perfectly calm weather, when not a breath stirs the sails ; 

 high, blue, and foamless the liquid masses succeed one another 

 at intervals of 200 to 300 yards, pass under the ship in silence, 

 and pursued by other waves are lost in the far distance. One 

 contemplates wdth a feeling of admiration, not unmixed with terror, 

 the calm and majestic wave advancing like a moving rampart, as if 

 about to swallow up all before it, and yet hardly leaving a sign to 

 mark its passage. These waves appear with surprising regularity, 

 during the autumnal calms, under the tropic of Cancer, and almost 

 at every season in the narrower part of the Caribbean Sea towards 

 the Gulf of Darien ; there the waves are seen silently to advance, 

 and slightly raise the ship, passing onward with scarcely a murmur, 

 as regularly as the furrows of a field, and stretching as far as the eyo 

 can see. 



