Chapter XV 



SCIENCE AND MYSTICISM 



One day I happened to be occupied with the subject 



of "Generation of Waves by Wind". I took down the 



standard treatise on hydrodynamics, and under that 

 heading I read — 



The equations (12) and (13) of the preceding Art. enable us 

 to examine a related question of some interest, viz. the generation 

 and maintenance of waves against viscosity, by suitable forces 

 applied to the surface. 



If the external forces p' yy , p'^ be given multiples of «***+**, 

 where k and a are prescribed, the equations in question determine 

 A and C, and thence, by (9) the value of tj. Thus we find 



P'vv _ (^ + 2yffflS + Q 2 ) A - i ((T 2 + 2vkma) C 

 gprj "" gk(J- iC) l 



£*v___a 2hk 2 J + (a + 2yg| C 

 gprj-gk' (J-iQ " 



where o 2 has been written for gk -\- T r k z as before. . . . 



And so on for two pages. At the end it is made clear 

 that a wind of less than half a mile an hour will leave 

 the surface unruffled. At a mile an hour the surface is 

 covered with minute corrugations due to capillary waves 

 which decay immediately the disturbing cause ceases. 

 At two miles an hour the gravity waves appear. As 

 the author modestly concludes, "Our theoretical investi- 

 gations give considerable insight into the incipient stages 

 of wave-formation". 



On another occasion the same subject of "Generation 



316 



