viii PREFACE. 



Ill the present volume I have attempted to supply 

 this want ; and for my materials have drawn chiefly 

 on my own twelve years' experience of the eastern 

 and western tropics of the equatorial zone, where the 

 characteristic phenomena of tropical life are fully 

 manifested. 



So many of the most remarkable forms of life are 

 now restricted to the tropics, and the relations of these 

 to extinct types which once inhabited the temperate 

 zones open up so many interesting questions as to the 

 past history of the earth, that the present inquiry may 

 be considered a necessary preliminary to a study of the 

 problem — how to determine the climates of geologic 

 periods from the character of their organic remains. 

 This part of the subject is however both complex and 

 difiicult, and I have only attempted to indicate what 

 seem to me the special physical conditions to which 

 the existing peculiarities of tropical life are mainly due. 



The three opening chapters treat the subject under 

 the headings of climate, vegetation, and animal life. 

 The conditions and causes of the equatorial climate 

 are discussed in some detail, and the somewhat complex 

 principles on which it depends are popularly explained. 

 In the chapters on plant and animal life, the general 

 aspects and relations of their several component elements 

 have been dwelt upon ; all botanical and zoological 

 details and nomenclature being excluded, except so far 



