THE CONQUEST OF ARID AMERICA 



been extensively done, but doubtless will be in the 

 future. 



The soil of arid "Washington is generally a light, sandy 

 loam, or volcanic ash. Some portions of the river-bot- 

 toms have extensive tracts of dark alluvial soil, while in 

 other portions the soil is so sandy as to drift before the 

 wind. While alkali is frequently encountered in small 

 spots, the soil as a whole may be described as free of both 

 alkali and clay. Its depth and texture are such as to in- 

 sure good drainage, which is essential in connection with 

 irrigation. Rich in potash, lime, and phosphoric acid, 

 the soil should prove enduring, as it has already proven 

 extremely productive. 



The climate is mild, though distinctly of the temperate 

 zone. The temperature sometimes goes as high as 108 

 in summer days, and as low as zero in winter nights ; yet 

 the climate is not severe, in spite of these figures. The 

 rainfall varies in different localities. On the sage-brush 

 plains of the Columbia it averages only about six inches, 

 which is less than in any other part of the United States 

 except the extreme Southwest. The resulting dryness 

 robs the summer heat and the winter cold of their worst 

 effects. In the warmer part of the region snow falls 

 rarely and seldom remains on the ground more than 

 two or three days. Along the Columbia river ploughing 

 can be done almost continuous!} 7 , while at the higher 

 elevations it is suspended from the middle of November 

 to the middle of February. Cyclones, tornadoes, and 

 blizzards are entirely unknown, and the frequent thun- 

 der-storms are so gentle as hardly to deserve the name. 

 There is more or less wind at all seasons of the year. 

 This is frequently strong enough to raise considerable 



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