only during fractions of a second. If a phenomenon lasts only a short 

 time, the eye is thus much more sensitive than the film. Let us give as 

 an example the shooting stars, which must be studied entirely by the 

 eye. Only the brightest can be photographed. 



The same thing is true of the phosphorescent submarine animals. 

 We have to see them ourselves : to take instantaneous exposures the\' 

 are not luminous enough, and for time exposures they are too mobile. 



Why are these animals phosphorescent ? Why have some of them 

 veritable headlights ? Is it to see their prey ? Is it to frighten off their 

 enemies ? To blind them ? Is it to recognize each other, as our glow- 

 worms do ? It is possible, too, that a part of these phosphorescences are 

 of no use at all, that they are simple consequences of chemical reactions 

 which accompany certain vital processes. If we take a walk, after rain on 

 a warm summer night, in our forests we sometimes find pieces of rotten 

 wood which emit a faint light, engendered by the mycelium of certain 

 fungi : no one would think that these bits of wood or their guests have 

 any purpose in this. 



So many questions, so many mysteries. It is only by ^oing down 

 ourselves to the depths of the sea that we can hope to clear them up. 



Let no one say that these observations are purposeless. No one can 

 foresee the resources that future generations will find in the ocean. Let 

 us remember, for example, that nature took millions of years to decom- 

 pose the organic matter of the marine sediments and make petrol of it : 

 did high pressures play a part in these reactions.'^ Will industry ever 

 come to speed them up to such a point that, instead of looking for 

 petrol, we shall be able to make it ? 



The organic matter formed annually in the seas is doubtless a 

 multiple of what agriculture produces over the entire earth. It is not 

 impossible that one day we shall find in the sea the food that the fields 

 can no longer furnish us with. Already today entire populations live 

 from fishing. But perhaps by using the plankton more directly — algae, 

 diatoms and minute crustaceans — humanity will find enormous re- 

 sources in the seas, which cover three-quarters of the globe. 



Throughout this field of exploration it is oceanography which will 

 guide humanity. How is that to be ? I cannot say. But the fact has been 

 proved many times already : all scientific research sooner or later bears 

 fruit. 



[M7] 



