m PREFACE. 



region, is clue, principally, to the tropic heat of the 

 ocean current Ku-ro Si-wa which, striking the 

 Alaska coast, is deflected southward, where it is de- 

 tained by the many promontories and islands of the 

 far-stretching Pacific Coast, while the southeast trade- 

 winds flowing over the accumulated warm water, 

 beconie saturated with moisture, which they carry 

 upon the continent, where, meeting with cool eleva- 

 tions of hill and mountain, the vapor is condensed 

 and deposited in torrents upon the coast, diminishing 

 by exhaustion, as it passes inland from range to range 

 of mountains, finishing with a slight rainfall upon 

 the vertebra of the continent the far-away Rocky 

 Mountains. 



In considering the power and tendency of these 

 two fundamental climatic agencies, we should expeet 

 to find the densest forest, the greatest variety of trees, 

 and the largest growth of trunk, cone, and leaf in the 

 abundantly watered and moderately heated mountains 

 of the Pacific Coast and such is the exact revealed 

 result. 



