indications, and it may be assumed that the average for the entire 

 region is not far from 20 inches. With this may be compared 26.32 

 inches, the average annual precipitation for the middle of the State, 

 and 34.33 inches for the eastern part. 



It is noteworthy that most of the precipitation on the plains is dur- 

 ing the growing season. Dodge City, for instance, with only 19.84 

 inches annually, has 15.5 inches in the six months from April 1 to 

 October 1. Rochester, N. Y., with 35 inches annually, has but 17.5 

 during the same period. In other words, 78 per cent of the precipita- 

 tion at Dodge City comes at the time when it is most needed, while 

 Rochester receives but 50 per cent of its total in the same time. 



One of the most disagreeable characteristics of the climate of the 

 Plains is the high winds, which sweep across them unhindered by 

 either natural or artificial barriers. The prevailing direction is north- 

 west in winter and southerly in summer, and soil moisture is absorbed 

 with extraordinary rapidity, especially in the warm season. The 

 dreaded " hot wind," which strikes growing crops with such deadly 

 effect, is a hot, dry blast of air that takes water from the leaf sur- 

 faces of vegetation faster than it can be supplied by the roots; con- 

 sequently plants wilt, and even die, if the wind is long continued. 

 The northerly winter w 7 inds, while causing much less evaporation, 

 are hard upon stock and trying for men. 



The average wind velocity at Dodge City, Kans., is 12 miles per 

 hour. In spring, however, it is considerably higher, especially in the 

 afternoon hours, when an average speed of 20 miles an hour may be 

 maintained for a month at a time. High winds are also quite fre- 

 quent. In the ten years ending with 1903 there were eighty-one 

 occasions on which the wind blew at the rate of 40 miles and upward 

 an hour. 



As a result of these constant drying winds, taken in connection with 

 other meteorological conditions which prevail in western Kansas, the 

 annual evaporation from a water surface is about 54 inches. This 

 means that if it were possible to have a lake in western Kansas whose 

 level depended wholly upon direct precipitation and evaporation, its 

 annual decrease in depth would be 34 inches. The relative humidity, 

 according to the Dodge City record, averages 60 to 65 per cent. The 

 following table is especially instructive: 



Annual precipitation and evaporation. 



60616 Cir. 10109 2 



