PREFACE. 7 



which has been an object of enlightened curiosity to 

 naturalists and travellers for more than twenty centu- 

 ries ; and, so far as possible, I have preferred rather to 

 cite the testimony of well-known writers than to seem 

 to claim the merit of discovery, by stating, on my own 

 authority, facts which others had observed before me. 

 Besides this, it has been agreeable to me thus to bear 

 witness to the accuracy of observation and fidelity of 

 description which characterize the writings of Taver- 

 nier, and Erman, and Bergmann, and Denham, and 

 Burckhardt, and other votaries and too often victims 

 of science, whose labors have done so much to facilitate 

 the researches of later explorers in the same attractive 

 field of knowledge. 



The information which I have thus collected, and 

 which I now lay before the public, has an important 

 bearing on a question that the American government is 

 bringing to a practical test. If the experiment shall 

 fail, it will be neither because the attempt is in its na- 

 ture hopeless, nor because the public agent entrusted 

 with the charge of it, has committed any error in the 

 execution of his duties, but because the means appro- 

 priated by Congress did not admit of an experiment on 

 a scale extensive enough, and varied enough, to em- 

 brace all the reasonable chances of success. In any 

 event, the present able Secretary of War, is entitled to 



