CHAP. VI CLIMATE 47 



above the sea. This is very noticeable in small mountainous isiountain 

 islands like Jamaica and Dominica, for whilst at the sea level ^ '"^^'^^^• 

 the climate is hot and tropical, in the higher mountains it 

 becomes cool and temperate. On the sea coast the mango 

 and the sugar cane and the cocoa-nut flourish, whilst Euro- 

 pean fruits and vegetables cannot be cultivated ; but in the 

 heights of the mountains, the mango and cocoa-nut will 

 not thrive, and yet European plants live and fruit and may 

 even run wild, as in the case of the strawberry on the 

 Jamaica cinchona plantations. 



Forests exert a very marked effect on climate, especially Forests. 

 in the tropics, the dense foliage preventing the rays of the 

 sun from reaching the earth, and thus the atmosphere is 

 affected by cool vapours. When the forest is cleared away, [;"^jl.^j^^^r 

 however, and the land is brought into cultivation, the air and warmer. 

 becomes drier and warmer, and so does the soil also. A 

 similar effect takes place when swampy and marshy land is 

 drained and brought into cultivation. 



When the atmosphere is loaded with clouds and vapours 

 as is the case in all maritime countries, the climate is much 

 more equable than in the interior of the continents. But 

 lakes and marshes have a bad effect on climate ; they give 

 rise to fogs, especially at night, which chill the ground 

 and render the place unhealthy. 



Aspect has also an effect on climate, a northern and an Aspect 

 eastern aspect being, as a rule, colder and moister than 

 southerly and westerly ones ; but, as aspect depends on the 

 sun, in a mountainous country it is often affected by the 

 lay of the land ; ridges, alternating with valleys or ravines, 

 causing a wide difference in the climate of places near to 

 each other. In a narrow valley, one side, being mostly in Valleys, 

 the shade, may be cool and damp whilst the other side is 

 warm and dry, and thus plant life would differ materially on 

 either slope. 



Exposed and windy situations have a different climate from Exposure, 

 sheltered places, although the soil and rainfall and aspect 



