THE WASTE AND GAIN OF THE DRY LAND. 405 



of the emerged soil, for the space they occupy is taken from the 

 sea. The sea, moreover, does not eat away all the shores. There 

 are coasts where the waves, instead of carrying away parcels of 

 the dry land, operate to fill up the bays and to add to the littoral 

 and prolong it in the direction of the sea. Thus the ocean every 

 year deposits several million cubic metres of sand along the 

 shores of the Gulf of Gascony. 



Another accrement which has a right to be regarded as con- 

 siderable is contributed by the legions of polyps constructing 

 resfs and atolls of coral, to which is due the building up of whole 

 archipelagoes in Oceania and the Indian seas. The islands formed 

 by these minute zoophytes are growing continually in extent and 

 number, and are probably destined ultimately, by joining, to give 

 rise to vast lands, real continents, which will gradually occupy 

 the immense voids of the Pacific. 



The shells of numerous species of animals and other remains 

 of dead organisms, meteorites and cosmic dusts falling from celes- 

 tial space, certainly produce further sensible augmentations of the 

 continental mass. 



Another essential cause of increase of dry land that might be 

 added is the decrease of the ocean itself in consequence of infil- 

 trations of water through the crust of the earth, which is a kind 

 of porous mass, into which the liquid element percolates by in- 

 numerable fissures, taking possession of the depths and directing 

 itself slowly toward the center, as the internal fire diminishes 

 and the crusts crack open in consequence. It is understood that 

 the activity of volcanoes and many earthquakes is largely due 

 to this inevitable penetration of the water, which internal heat 

 transforms into vapor under pressure. Some geologists think 

 that the primitive ocean has already diminished in this way one 

 fiftieth of its volume. 



The water is all destined to disappear from the surface of the 

 globe by being absorbed by the subterranean rocks, with which 

 it will form chemical combinations. The heavenly spheres ex- 

 hibit sufficiently striking examples of such an evolution. The 

 planet Mars shows what will become of the earth in some thou- 

 sands of centuries. Its seas are only shallow Mediterraneans of 

 less surface than the continents, and these do not appear to be 

 very high ; and in the appearance of the moon, all cracked and 

 dried up, we have a view of the final state of the earth for the 

 absorption of the water by the solid nucleus will be followed by 

 that of the atmosphere. 



We see, therefore, M. Ldotard continues, that not only is there 

 no equilibrium in the struggle between the oceans and the conti- 

 nents, but that, inversely to the conclusions of M. de L' Apparent, 

 the event that may be considered very probable in a future repre- 



