Climate 187 



true even with regard to the vine, whicli, though a 

 native of warm chmates, still is not a tropical plant, 

 and is accustomed to shed its leaves year by year. In 

 the tropics, however, its leaves remain green, instead 

 of giving up their stores to feed the fruit as they ought ; 

 the grapes fall off almost unformed, and the vine puts 

 all its energy into growing leaves instead of fruit, not 

 having strength for both. The one thing which it lacks 

 is rest — the rest which in winter it is compelled to 

 take. 



It being, however, impossible to provide the vines 

 with winter-cold in Ceylon, it was suggested that heat 

 might perhaps be made to answer the purpose as well, 

 and the experiment was tried of laying the roots bare 

 for a time to the strongest sun. This had the effect of 

 checking the flow of sap as effectually as frost could 

 have done : the leaves dropped, the vines had their 

 sleep, and awoke from it so refreshed and invigorated 

 that they were able to bring their crop to maturity ; 

 and this plan has been adopted with success both in 

 Ceyljn and Bombay. 



In those tropical regions, outside the equatorial belt, 

 where there are periodical rainy seasons and long 

 droughts, the latter answer all the purpose of winter, 

 and are, indeed, winter, so far as vegetation is con- 

 cerned, in spite of their intense heat. Trees and shrubs 

 are as leafless in the desert of Nubia, for instance, 

 before the rains set in, as if it were mid-winter, in spite 

 of, or, rather, in consequence of, the terrible heat ; and 

 thus a time of rest is secured to them. 



In the far north we have a very different state of 

 things. Here, instead of its being necessary to sccuro 

 that the plants shall have rcot, the great thing is to 



