“So the sea ought always to be calm,” said Jules.
“It would be a pity, my child, if the sea were always at rest. This calm would be incompatible with the salubrity of the seas, which must be violently stirred up to keep them free from taint and to dissolve the air necessary to their animal and vegetable population. For the ocean of waters, as for the atmosphere or ocean of air, there is need of a salutary agitation—of tempests that churn up, renew, and vivify the waters.
“The wind disturbs the surface of the ocean. If it comes in gusts, it creates waves that leap with foaming crest and break against one another. If it is strong and continuous, it chases the waters in long swells, in waves or surges that advance from the open in parallel lines, succeed one another with a majestic uniformity, and one after another rush booming on to the shore. These movements, however tumultuous they may be, affect only the surface of the sea; thirty meters down the water is calm, even in the most violent storms.
“In our seas the height of the biggest waves is not more than two or three meters; but in some parts of the South Sea the waves, in exceptional weather, rise to ten or twelve meters. They are veritable chains of moving hills with broad and deep valleys between. Whipped by the wind, their summits throw up clouds of foam and roll up in formidable volume with a force sufficient to shatter the largest vessels under their weight.
“The power of the waves borders on the prodigious. There, where the shore, rising vertically from the water, presents itself fully to the assaults of the sea, the shock is so violent that the earth trembles under one’s feet. The most solid dikes are demolished and swept away; enormous blocks are torn off, dragged along the ground, sometimes thrown over jetties, where they roll like mere pebbles.
“It is to the continual action of waves that cliffs are due, that is to say the vertical escarpments serving in some places as shore for the sea. Such escarpments are seen on the coasts of the English Channel, both in France and in England. Unceasingly the ocean undermines them, causes pieces to fall down which it triturates into pebbles, and makes its way so much farther inland. History has preserved the memory of towers, dwellings, even villages, that have had to be abandoned little by little on account of similar landslides, and that to-day have entirely disappeared beneath the waves.”
“Stirred up like that, the waters of the sea are not likely to become putrid,” remarked Jules.
“The movement of the waves alone would not suffice to insure the incorruptibility of sea-water. Another cause of salubrity comes in here. The waters of the sea hold in solution numerous substances that give it an extremely disagreeable taste, but prevent its corruption.”
“Then you cannot drink sea-water?” Emile asked.
“No, not even if you were pressed with the greatest thirst.”