OCEANOGRAPHY. 415 



must admit that we are in this respect undeniably inferior to other 

 nations. Still plunged in lamentable ignorance and regardless of the 

 information obtained by careful scientific experiments, we ravage our 

 coasts, and statistics show that the fishing industry is incapable of 

 furnishing daily bread to those who practice it at the cost of so much 

 trouble, fatigue, and danger. We profit by the sea as savages profit 

 by the earth, when, according to the famous simile, finding a fruit tree 

 in the forest they cut it down to gather its fruit. We have no com- 

 plete and detailed map, not even a mediocre one, of the sea bottom, 

 nor have we any exact ideas of the variations in temperature, in 

 density, in salinity, along our coasts; we have not calculated the 

 amount of sediment deposited by any of our great rivers; we are 

 ignorant to what depth currents are felt and, except for a very small 

 number of localities, as to their direction on the surface; we have no 

 idea of their variations in intensity at different periods of the year. 

 It is only too easy to add to tins list of the data which we now lack. 

 However full of good intention the measures of the administration 

 may be, they are fruitless if they have not the intervention of author- 

 ity to sanction the application of the measures approved by science. 

 How can we be astonished by the poverty of our fishers and the fatal 

 consequences which can not fail to affect the country? Fish are an 

 important item in the economies of nations. According to statistics 

 now somewhat old but rather increased than diminished by time, the 

 world captures and consumes annually 2,000,000,000 francs worth of 

 fish. 



The industry of laying submarine telegraphs depends on oceanog- 

 raphy to the same extent that the construction of railroads or canals 

 depends on topography and continental geology. Perhaps the depend- 

 ance of the telegraphs is even greater. The railroad and the cable 

 follow the contour of the soil; both, for analogous reasons, must avoid 

 too irregular ground, and the nature of the bottom is of the utmost 

 importance. On certain bottoms swept by currents, as on the Wyville 

 Thomson reef to the north of Scotland, the cable, subject to continual 

 vibrations against the pebbles or frayed by their unceasing friction as 

 they are washed about by the movement of the waves, wears out and 

 breaks, however solid its envelope may be. At other times, on volcanic 

 bottoms, as near Greece, for example, or in the Malay Archipelago, the 

 cable may be stretched by displacement of the ground, causing changes 

 in the level which break it. 



The landing of the cables is no less important. Rocks are always 

 very dangerous if they are situated in the zone of action of waves and 

 tides. While in the open sea the land has every chance of being uni- 

 form, near the coast it often becomes irregular. It presents sudden 

 declivities or deep hollows, reefs, straight crevasses bounded by almost 

 perpendicular walls, such as M. Pruvot has recently discovered, not 

 in some unknown corner of the Pacific or the South Sea, but in the 



