INFORMATION FOR EMIGRANTS. 7 



Maj. Powell says (page 56) of Arizona and New Mexico: 



In all this region the daily range of temperature is great, and frosts 

 occur so early in autumn that no use can be made of the autumnal rain- 

 fall. The yearly precipitation is very small, and the summer quota 

 rarely exceed seven or eight inches. 



The arguments that the rain-fall will increase with the coming of man 

 ■on the western plains is shown to be fallacious by the following state- 

 ment from report quoted above (page 74) : 



The area affected by grazing is far greater than that affected by farm- 

 ing. Cattle, sheep, and horses have ranged through all the valleys, and 

 upon all the mountains. Over large areas they have destroyed the native 

 grasses, and they have everywhere reduced them. Where once the 

 water from rain was entangled in a mesh of vegetation, and restrained 

 from gathering into rills, there is now only an open growth of bushes 

 that offer no obstruction. Where once the snows of autumn were 

 spread on a non-conducting mat of hay, and wasted by evaporation, 

 until the sunshine came to melt them, they now fall upon naked earth, 

 .and are melted at once by its warmth. 



If the above statement be true, the air must become dryer, and the 

 amount of rain-fall less, and the waste of the water so great that little 

 would be available during the summer months for purposes of irriga- 

 tion. 



Timber and Woodlands. 



The great area extending across the Vnited States from north to 

 -south between longitude 97° and the Rocky Mountains is almost des- 

 titute of forest growth. Probably not one per cent, of this area is 

 woodland. The need of forests is so well told in the great work of 

 George P. Marsh, that I advise all who can obtain access to it to read 

 it. In discussing the due proportion of woodland requisite, he says : * 



The proportion of woodland that ought to be permanently maintained 

 for its geographical and atmospheric influences, varies according to the 

 character of the soil, surface, and climate. In countries with a humid 

 -sky, or moderately undulating surface and an equable temperature, a 

 small extent of forest, enough to serve as a mechanical screen against 

 the action of the wind in localities where such protection is needed, 

 suffices. But most of the territory occupied by civilized man is exposed, 

 by the character of its surface and its climate, to a physical degradation 

 which cannot be averted except by devoting a large am.ount of soil to 

 the growth of woods. 



From an economical point of view, the question of due proportion of 

 :forest is not less complicated or less important than in its purely physical 



*The Earth Modified by Human Action: New York, 1877, page 302. 



