WAVE-ACTION IN NATURE. 



Fig. 4 



Chlajdni's Figuees of Yibkating Plates. 



that to the third, and so on, while the last ball only of the row flies 

 away. The balls being elastic, the first one struck is not pushed from 

 its position, but is slightly compressed, and then expanding it com- 

 presses the second, which, again expanding, compresses the third ; 

 and so there is propagated a series of compressions and expansions 



