vi PREFACE. 



In " The Tropical World," my additions to the labors of Dr. Hartwig 

 have been much more considerable. Since his work was written, im- 

 mense additions have been made to our knowledge of portions of the 

 reo-ion lying Avithin the Tropics. Squier has traversed the plateaus of 

 Bolivia and Peru; and apart from the abstracts of his journeys which he 

 has published, he has favored me with much information to be embodied 

 in the great work upon which he has for years been engaged. Holton 

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

 has 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. Anders- 

 soisr and Baldwin have told their hunting adventures in Southern 

 Africa ; Barth has traversed the great Sahara ; Speice and Baker 

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

 pierced the continent on the line of the equator, and described the mys- 

 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 INIahiy Archipelago, a group of islands sur- 

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

 almost uninhabited, capable of sustaining a population greater than that 

 now livinsj 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. They 

 present to the eye information Avhich words would often be inadequate 

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

 not be foimd unworthy of the foundation laid by Dr. Hartwig. 



Alfred H. Guernsey. 



