268 

 earth 



DEPTHS OF THE OCEAN 



This wave has a very great length, with high - water 

 at the crest and low- water in the trough. Its form remains, 

 fettered by the moon, while the earth revolves beneath it. 

 Passing the opening between Africa and South America, it 

 gives rise to a lateral wave moving from south to north through 

 the Atlantic. This tide-wave reaches the coasts of northern 



Fig. 179. — The Currents on the Ling Bank in the North Sea (7th-8th August 1906). 



Europe, producing tidal effects there. But besides this wave 

 coming from the Southern Ocean there is formed an Atlantic 

 tide-wave following the movement of the sun and moon from 

 east to west. As already remarked, these things are somewhat 

 enigmatical, but as there is a connection between tidal waves 

 and tidal currents, we may hope that careful current-observations 

 will contribute to the unravelling of these problems. 



