412 OCEANOGRAPHY. 



applications of this method have been made in France by Commander 

 de Koujoux and by Captain Trudelle for landfalls in different localities, 

 along the Channel, at the entrance to New York, Havre, Brest, and the 

 very dangerous approaches to Cape Guardafui. Two oceauographic 

 coordinates have taken the place of the astronomical coordinates. The 

 vessel, having lost her sight, makes use of feeling. To draw up bathy- 

 metrical and lithological charts is one of the principal objects of ocean- 

 ography. 



Oceanography has to maritime fisheries a relation still more impor- 

 tant, if that is possible, than to geology, meteorology , and navigation, for 

 this industry is related closely to the very life of nations. In France we 

 have more than 86,000 marine fishermen, while more than 200,000 people 

 derive, directly or indirectly, their means of existence from fishing; as, 

 for instance, the men and women employed in the canning factories. 



There are very many marine animals of which man makes use either 

 as food, such as fishes, crustaceans, certain mollusks such as oysters 

 and mussels, or to gratify his needs of all sorts, as sponges, pearls, coral, 

 the great cetaceans, as whales or cachalots, and seals, from which he 

 obtains oil and skin. No being escapes from the influence of the sur- 

 roundings in the midst of which he lives and which govern his material 

 existence as well as his manners, his morals, and his intellectual facul- 

 ties. Nowhere are these restrictions more strikingly evident than in 

 the water, probably because they are found there in a state of the 

 greatest simplification or, to be more exact, the least complication. The 

 laws of oceanography are, then, the rational basis for the conduct of 

 fisheries, which have become methodical and consequently scientific, 

 and pisciculture is a kind of agriculture of the sea. 



In the harmony between a being and his environment, three cases 

 X>resent themselves: If the harmony is perfect, the being, finding the 

 utmost satisfaction for his needs, develops and multiplies ; if it is only 

 partial, the being who suffers it becomes rare; if, finally, the harmony 

 is absent, the being will disappear by flight if he possesses, like an 

 animal, the power of motion, or by death if, like a plant, he is con- 

 demned to remain in one place. The living creature thus indicates in 

 three ways the condition of his surroundings — by his presence, his 

 rarity, or his absence. Dredgings made even in great depths show 

 in a striking way the extreme specialization in the distribution of the 

 animal species, among which some are evidently more sensitive to the 

 environment, others less so. Each special group conforms to correspond- 

 ing, special, exterior conditions, physical, chemical, or mechanical, and 

 in this way the animal, vegetable, and, to a certain degree, even the 

 mineral becomes an instrument of measurement, roughly graduated, it 

 is true, because while abundance or absence are relatively easy to rec- 

 ognize, nothingis more vague and less determinable than degrees of rar- 

 ity. A fish found in a certain locality indicates that the water there 

 possesses a depth, a temperature, a certain limited range of salinity, a 



