RAIN AND PLANTS. 291 



in the structures of the trees, particularly in 

 the leaves and young brandies, and rain was 

 the chief instrument by which they were in- 

 troduced. Being produced in the soil by virtue 

 of processes which have already come under 

 notice, they assume a soluble form, become 

 dissolved in the rain-water as it trickles down 

 from the surface to the roots, and are then 

 absorbed and appropriated by the spongioles of 

 the plant. It is curious that a shower produces 

 a stream of water actually containing more salts 

 and earthy matter than the water which trickles 

 slowly through the ground. Rain, by softening 

 the ground, renders the matters therein con- 



O * 



tained more soluble. 'The frosts of winter break 

 up the ground, and the succeeding rains of 

 spring supply the roots of plants with an abun- 

 dance of soluble matter, then so important to 

 them. 



As a mere mechanical agency, rain is also of 

 great service to plants. Any one who has seen 

 the accumulation of dust and dirt which the tur- 

 moil and bustle of human society causes to rise 

 and be deposited on all vegetation within its 

 reach, and has again noticed the fresh and cheer- 

 ful aspect of the vegetable creation when a new- 

 fallen shower has been succeeded by a clear sky, 

 will perceive the importance of this function also 

 to the well-being of vegetation. The particles 



