vi PREFACE. 



In "Tlie Tropical World," my additions to the labors of Dr. Hartwii;- 

 have been luucli more considerable. Since liis work was written, im- 

 mense additions liave l)cen made to onr knowledge of portions of the 

 region lying within the Tro])ics. S(,)UIER has traversed the plateaus of 

 r)olivia and Peru; and apart from the abstracts of his journeys which he 

 has publislied, li<; has favored me with much information to be embodied 

 in the great work upon whicli he has for years been engaged. HoLTOX 

 has furnished a curious book on the great table-land of Bogota; Oktox 

 lias crossed the Andes, explored the Valley of Quito, and descended the 

 Amazon from its upper waters to its mouth; and Agassiz has made 

 large contributions to our knowledge of the natural history of the mighty 

 Valley of the Amazon. 



Our knowledge of the hitherto almost unknown parts of Africa has 

 been more than doubled since Dr. Hartwig prepared his work. Andeiis- 

 SON and Baldwin have told their hunting adventures in Southern 

 Africa; Baeth has traversed the great Sahara; Speke and Bakek 

 have solved the mystery of the source of the Nile ; Du Chaillu has again 

 pierced the continent on the line of the equator, and descrilied the m^s- 

 teries of the home of the gorilla. 



Perhaps the most entirely fresh account of a part of the Tropical World 

 is Wallace's work on the Malay Archipelago, a group of islands sui-- 

 passing in extent all the inhabitable parts of Europe, and, although now 

 almost uninhal)ited, capable of sustaining a population greater than that 

 now living outside of China and India. 



Of all these, and many more authorities, I have made free use ; and in 

 both parts of the work, I have steadily kept in view the leading idea of 

 Dr. Hartwig : To describe the Polar and Tropical Worlds in their prin- 

 cipal natural features, and to point out the influence of their respective 

 climates upon the development of animal and vegetable life, and par- 

 ticularly upon human beings. 



The liberality of the Publishers has placed at my disposal illustrations 

 far exceeding in number and beauty those in the original work. Tliey 

 present to the eye inforiuation which words would often be inadecpiate 

 to express to the ear. I trust that my own additions to the work will 

 not be found luiwortliy of the foundation laid by Dr. Hartwig. 



AlFI;KI) il. (lUERXSEY. 

 Nkw York, March, 187L 



