124 ACTION OF THE ATMOSPHERE 



the most advantageous to vegetation, for plants almost 

 always require water. 



Mrs. B. It is to the dampness of our climate that we 

 owe the fine grass of our beautiful meadows and lawns, for 

 which England is so celebrated, and which are in vain at- 

 tempted to be imitated on the Continent ; unless it be in 

 some very elevated spots, where the grass is nurtured by 

 the mountain mists. It is to this cause, also, that we are 

 indebted for the prosperity of our laurels, and a variety 

 of evergreens ; yet a damp climate has its attendant disad- 

 vantages, even as regards the vegetable creation. Fogs 

 and vapor diminish the quantity of light, and, consequent- 

 ly, the numerous benefits resulting from it, such as absorp- 

 tion, evaporation, deposition of carbon, and developement 

 of color. In this point of view, therefore, a very moist 

 climate injures the beauty and vigor of vegetation. 



Trees growing on mountains, where they are much ex- 

 posed to vapor, are very liable to suffer from what is com- 

 monly called a white frost. The clouds and mists, so 

 prevalent in those elevated regions, bedew their branches 

 with a light coating of watery vapor, which easily freezes 

 during the night ; the morning mist attaches itself to this 

 thin layer of ice, and shoots into minute frosty crystals, 

 called a white frost. 



Caroline. The white frost, which we so commonly see 

 on the grass, is formed, I suppose, by the freezing of the 

 dew. 



Mrs. B. Yes ; and it is, you know, so light as to dis- 

 appear soon after the sun has risen above the horizon. 



Moisture is particularly inimical to blossoms : if it 

 comes in contact with the anthers, it destroys them, and 

 the flower bears no seed. This disease often affects the 

 vine, and not unfrequently corn, to the great injury of the 

 vintage and the cornharvest. Moisture is prejudicial, 

 also, by giving rise to the propagation of fungi, of para- 

 sitical plants, and even of worms. 



There are some plants to which the moisture of sea- 

 breezes is so essential, that they cannot be cultivated in 

 any other situation than on the shores of the ocean. 



692. What effect on vegetation does the dampness of climate produce"? 

 693. What unfavorable effects on vegetation are caused by fogs and va- 

 pors'? 694. What is said of trees growing on mountains'? 695. 

 How is white frost produced 1 ? 696. How does moisture effect blos- 



ms"? 697. What is said of the effects on vegetation from sea bree 



ji 



