PREFACE 



WE may regard the successful growth of the orange 

 tree as marking the outer limit of the subtropical re- 

 gions, where frosts are of short duration and the year 

 is divided into hot and cool seasons. The coconut 

 palm marks the boundary of the outer tropical belt, 

 which has also more or less distinct cool and hot sea- 

 sons, but as a rule no frosts. The equatorial belt, on 

 the other hand, has no distinct cool season. In the 

 subtropical regions, tropical vegetables may be grown 

 well in the hot season, and temperate vegetables, which 

 can survive any slight frosts that may occur, can be 

 very successfully raised in the cool season. In the 

 outer tropical or trade-wind belts, some temperate vege- 

 tables can be grown fairly well in the cool season. In 

 the subtropical and especially in the tropical lands, an 

 elevation of a few thousand feet produces a remarkable 

 change in the climate ; and temperate vegetables can 

 be cultivated at such a height even in the equatorial 

 belt, and still more successfully towards the borders 

 of the tropical belt. Thus the subtropical regions can 

 grow at different times of the year and at different 

 heights, nearly all the vegetables of the world. Except 

 in North India, where numbers of Europeans have re- 

 sided for a long time, and in certain subtropical coun- 

 tries like peninsular Florida, it is probable that the 



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