156 
NATURE FOR ITS OWN SAKE 
Dancing 
jets. 
The size of 
coast waves. 
lower part of the wave is not able to keep up 
with the upper part, the top is shot violently 
forward, and having no base to rest upon, 
breaks and falls upon the beach in spray. The 
cause of the dancing upward of the waves under 
the deep-based cliff will now be apparent. The 
base of the wave, meeting with no marked 
friction, moves as fast as the top and strikes 
the rock beneath the surface. The whole wave 
rebounds against the wave following it, and a 
push upward of the water in vertical points or 
dancing jets is the result. There is no other 
way for the water to move. 
It will not have escaped the notice of the most 
casual observer that the waves breaking upon a 
coast follow each other more closely than upon 
the open sea. The friction upon the waves as 
they reach shallow water—the drag upon the 
bottom—is also responsible for this. The front 
ones cannot move so fast as the rear ones, and 
there is a closing up of the ranks—sometimes 
a doubling or tripling of the waves. This at 
times results in the waves along shore being 
smaller than on the open sea, and again, in 
times of storm, it may result in their being 
larger. Certainly a storm on a rocky coast will 
throw the breaker-crest higher than upon open 
