16 



THE OPAL SEA 



Charting of 

 the sea. 



waters with their islands, reefs, and shoals, 

 but the sounding of the depths and the map- 

 ping of the ocean bed twenty thousand feet 

 below the surface; not only the study of its 

 winds and calms but the movements of its cur- 

 rents and the changes in its density and tem- 

 perature. Since the eighteenth century began, 

 all features of the ocean — from its coral islands 

 built up to its rocky shores pulled down, from 

 the glowing equator producing , the energy of 

 the great sea currents to the icy poles whose 

 chilling streams restore the equilibrium, from 

 the tides that swell the bays and harbors to 

 the evaporation that drinks at the sea's surface 

 — have been pried into and exploited. As for 

 the color and light of the wave, its rise and 

 fall and motion, they are no longer mysteries; 

 the flora of the shallows and the fauna of the 

 depths have been classified; and even the 

 minute forms of life that show only as phos- 

 phorescence upon the sea's surface have come 

 under the microscope, have been analyzed and 

 differentiated in the laboratory. 



Apparently all is known to us and the sea 

 has no further secrets to reveal. And yet in 

 a vague way we feel sure we are only on the 

 threshold of its understanding. The story of 

 creation becomes more intricate as we advance. 



Scientific 

 studtj of the 

 ocean. 



