SECT. 5] 



INTERNAL WAVES 



743 



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Fig. 14. Simple progressive internal wave between water of two densities. The large 

 arrow at the top shows the direction of the wave. The water motion streamlines are 

 shown by the small arrows and the most common location of the slick by the heavy 

 bar. 



B 



Fig. 15. A. Dye marker being dropped vertically. B. Its deformation, after a few seconds, 

 as a resxilt of differential movement in the water column above and below the thermo- 

 cline. 



