462 THE CHEMISTRY OF CREATION. 



the marine plants to recommence their duties, 

 and as the fresh waters sweep over them they 

 gain new life and vigour, and proceed with 

 their periodical task of decomposition upon 

 the gases held dissolved in the water. By 

 their return also the waters put a stop to 

 such of the chemical changes taking place in 

 the substances composing the coast, as require 

 the presence of atmospheric air. Soluble matters 

 in the soil are also dissolved out, and a supply of 

 water, free from the impregnations of the coast, 

 is periodically afforded to all the zoological in- 

 habitants of the shore zone. The consideration 

 of the varied processes of vital chemistry taking 

 place in the waters, is deferred to the next 

 chapter. 



As we look to the foaming edge of the ma- 

 jestic element now rolling at our feet, and 

 contrast the colour of the water, for several 

 yards off shore, with the purer and more trans- 

 parent tint of the waves at a greater distance, 

 we immediately become sensible of the fact, 

 that with every tide certain mechanical effects, 

 of greater or less amount, must be produced 

 upon the materials composing the sea-shore. 

 These heaving billows, which break so un- 

 ceasingly on the beach, creating that pecu- 

 liar sound, well described as the " voice of 

 many waters," in so doing churn up all the 



