A transatlantic steamer when moving expends a force of some tens 

 of thousands of horse-power which is pure waste : we can easily see 

 where this energy is going. Indeed, if at the bow the currents of water 

 separate in reasonably good order to allow the hull to pass, they are 

 joined together again behind in great disorder and the course of the 

 ship is marked across miles of ocean by the swirling of waters it has 

 produced. 



Are these eddies inevitable? The water currents could, however, 

 if they really wanted to, join up again behind the ship according to the 

 same laws that they observed when separating. Here is a magnificent 

 field for research for the naval engineer. To copy the dolphin, there is a 

 problem which is simple to propound. The solution is perhaps 

 difficult to find, but it is probably not impossible. 



I could imagine, for example, a ship, the hull of which would be 

 covered with a rubber membrane, under which a great number of 

 pressure gauges would be disposed. The slightest eddy at its origin 

 would affect these instruments. This perception is transformed into 

 electric current and transmitted to a central station, the electronic 

 brain of the ship which analyses all these impulses and determines the 

 movement which the 'skin' of the ship must be made to execute in 

 order to cancel the slightest eddy at its origin. To determine what is to 

 be done is the most delicate part of the problem. For, once this is 

 solved, the electronic brain will be able, without difficulty, to send out 

 electric currents of suitable force to little electro-magnets disposed in 

 great numbers between the pressure gauges, in such a way as to pro- 

 duce well-organized reactions in the 'skin' of the ship. 



In practice should we begin our trials with a surface ship or a sub- 

 marine ? I should choose the submarine without hesitation. In fact the 

 surface-frontier between air and water presents great difficulties, 

 difficulties that even the dolphin has not been able to surmount. We 

 see the dolphin moving majestically along in front of our ship just 

 below the surface. We observe the slow movements of his flippers and 

 the delicate wrinklings, apparently unsystematic, of his skin : we know 

 that it is these last which prevent the eddies. But the dolphin is a mam- 

 mal : from time to time he must put his nostrils out of the water to 

 breathe. Immediately something goes wrong : the system is disordered ; 

 there are showers of spray; the water swirls round the animal. What 

 energy is dissipated ! But an instant later the dolphin masters the situa- 

 tion, and once more we see him glide through the water in perfect 



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