I I 6 WHALES 



swam through the sea, while the seals caused a great deal of turbulence 

 -just one more bit of circumstantial evidence in favour of our assumption. 

 The difference between whales and dolphins is primarily due to their 

 difference in length - the longer the body the greater the turjjulence, and 

 the farther back the maximum girth the smaller the disturbance. We have 

 already seen in Fig. 41 that dolphins have their maximum dimensions 

 much farther back than Rorquals. Apart from the other explanations, the 

 difference between whales and dolphins may also be ascribed, at least 

 partly, to the fact that the structure of the spinal musculature in dolphins 

 shows a higher degree of efficiency than in whales (see page 109). Though 

 this, too, is circumstantial evidence, we see that scientists have begun to 

 approach the solution to the mystery of the speed of whales and par- 

 ticularly of dolphins. As investigations continue, more and more evidence 

 will no doubt come to light, and this evidence will probably be applied to 

 improving the construction and speed of ships, and especially of sub- 

 marines. May I express the hope that by the time such improvements are 

 made, there will no longer be any need for military measures, and also 

 that faster and better ships will not mean a more extensive persecution 

 of whales and dolphins. It would be very tragic, indeed, if these animals 

 were made to suffer for the knowledge they have imparted to us. 



