CHAPTER X. 



THE RHYTHM OF MOTION. 



82. WHEN the pennant of a vessel lying becalmed first 

 shows the coming breeze, it does so by gentle undulations 

 that travel from its fixed to its free end. Presently the sails 

 begin to flap; and their blows against the mast increase in 

 rapidity as the breeze rises. Even when, being fully bellied 

 out, they are in great part steadied by the strain of the yards 

 and cordage, their free edges tremble with each stronger 

 gust. And should there come a gale, the jar that is felt on 

 laying hold of the shrouds shows that the rigging vibrates; 

 while the rush and whistle of the wind prove that in it, also, 

 rapid undulations are, generated. Ashore the conflict be- 

 tween the current of air and the things it meets results in a 

 like rhythmical action. The leaves all shiver in the blast; 

 each branch oscillates; and every exposed tree sways to and 

 fro. The blades of grass and dried bents in the meadows, 

 and still better the stalks in the neighbouring corn-fields, 

 exhibit the same rising and falling movement. Nor do the 

 more stable objects fail to do the like, though in a less mani-. 

 fest fashion; as witness the shudder that may be felt 

 throughout a house during the paroxysms of a violent 

 storm. Streams of water produce in opposing ob- 



jects the same general effects as do streams of air. Sub- 

 merged weeds growing in the middle of a brook, undulate 

 from end to end. Branches brought down by the last flood, 

 and left entangled at the bottom where the current is rapid, 



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