8 GENERAL, VIEW OF THE GEOGRAPHY. 



difference in temperature between the day and the succeeding night is, 

 at all seasons, but particularly in summer, greater than in the countries 

 nearer to the ocean. It is scarcely necessary to add, that, in territories 

 so scantily and irregularly supplied with water, the surface must be, in 

 general, bare and destitute of vegetation ; and such is the character of 

 the greater portion of the continent west of the dividing range of 

 mountains. 



The central regions of the continent east of the Rocky Mountains 

 exhibit, though in a less degree, the same peculiarities of climate with 

 those adjoining, in the Pacific section. The vast plains, extending from 

 the vicinity of the dividing chain towards the Mississippi, south of the 

 50th parallel of latitude, are almost as arid and barren as the countries on 

 the other side of the ridge ; the rains are neither frequent nor heavy 

 during the warm months, and the surface, except in a few spots near the 

 rivers, consists of sand and sandstone strongly impregnated with salt, 

 and affords support only to stiff grass and shrubs. Descending towards 

 the Mississippi, the climate and soil become more favorable to vegetable 

 life, and the country gradually assumes the characters of the other Atlan- 

 tic regions. North of the 50th parallel, there is more rain or snow, at all 

 seasons, on each side of the ridge, though less on the west than on the 

 east; the intensity of the cold, and its long duration, particularly on the 

 eastern side, render those territories almost all uninhabitable by those 

 who depend on agriculture for subsistence. 



In consequence of this greater aridity of the climate on the western side 

 of America, the irregularity of the surface, and the proximity of the 

 dividing chain of mountains to the coast, the rivers on that side are 

 generally neither so long, nor so abundant in water, nor navigable to 

 such distances from their mouths, as those which fall into the Atlantic. 

 The Columbia and the Colorado are the only streams known to flow from 

 America into the Pacific, which can be compared, in any of these 

 respects, with several in the other sections of the continent.; yet they 

 are each certainly inferior to the St. Lawrence, the Mississippi, the 

 Orinoco, the Amazon, and the Plate, and probably, also, to the Macken- 

 zie. These and the other rivers of Western America run, in nearly their 

 whole course, through deep ravines, among stony mountains; and they 

 are, for the most part, crossed at short intervals by ledges of rock, pro- 

 ducing falls and rapids, which render all navigation on them impossible, 

 and to overcome which, all the resources of art would be unavailing. 



In the territory east of the dividing chain, and south of the 50th paral- 

 lel of latitude, are many rivers flowing from the mountains to the Missis- 

 sippi ; but none of them seem calculated to serve as channels for commu- 

 nication between the Atlantic and the Pacific regions. The Missouri and 

 the Yellowstone each take a devious course ; so that, after ascending 

 either of them to the head of its navigation, the distance to the habitable 

 countries on the Pacific is almost as great as from a point on the Missouri, 

 more than fifteen hundred miles below. The Platte flows nearly, under 

 the 42d parallel of latitude, from its source in the South Pass, the princi- 

 pal cleft of the Rocky Mountains, to the Missouri, precisely in the direc- 

 tion most favorable for intercourse between the Mississippi and the 

 Columbia countries; but it is the most shallow of all large rivers: travers- 

 ing a surface nearly plain, the increase of its waters, produced annually 

 by the rains and melting of the snows, only serves to render it wider, 



