292 THE CHEMISTRY OF CREATION. 



of dirt thus deposited, if not removed by some 

 means, would most seriously interfere with 

 the respiration of the plants. The stomata or 

 mouths of the leaves would become clogged up 

 and unfitted for the discharge of their peculiar 

 functions, and the most injurious consequences 

 to the health of the plant would ensue. But 

 the shower comes down, and, in a few minutes, 

 all is clean again ; every function is restored 

 to its due activity, and the scene assumes 

 a freshness of colouring quite peculiar to such 

 seasons. The remark does not seem to have 

 been previously made ; but, it may be sug- 

 gested, is not the glossy coating of evergreen 

 shrubs intended to facilitate this process, ren- 

 dered all the more necessary by the length of 

 time the leaves endure? 



As it restores cleanliness and freshness oi 

 garb to the vegetable world, so rain also exer- 

 cises a most beneficial influence upon the con- 

 dition of the atmosphere. It carries with it 

 the mass of carbonaceous particles which, owing 

 to the bad construction of our fire-places, are 

 cast forth into the air. It also brino-s down 



o 



that invisible, though not always inodorous 

 cloud of organic matters which float in the 

 atmosphere of populous places, and very pro- 

 bably renders, in many cases, these otherwise 

 dangerous ingredients of the air of towns com- 



