472 TRANSACTIONS OF THE STATE AGRICULTURAL SOCIETY. 



than five inches, has almost disappeared, and that in which the rainfall 

 was put down at less than fifteen inches, has been reduced by a quarter of 

 a million of square miles since the census map of 1880 was made. 



General Greely discussed the question of what constitutes an arid region, 

 and said that he does not agree with Major J. W. Powell, who placed the 

 minimum amount of precipitation necessary for successful agriculture at 

 twenty inches per annum. He said that millions of bushels of wheat are 

 raised every year where the rainfall is less than twenty inches, and referred 

 to the statistics of Dakota, where more than two million six hundred thou- 

 sand bushels were raised in the two counties of Richland and Stutsman 

 in 1885, and one million five hundred thousand in 1887, with an average 

 rainfall of 13.7 to 15.1 inches. 



General Greely also mentioned the interesting fact, that, while the rain- 

 fall increases as the rivers which flow directly into the Gulf of Mexico or 

 into the Pacific Ocean are followed up from their mouths, it increases with 

 the distance from the mouths of such as empty into other bodies of water, 

 like the Colorado. 



General Greely's charts also prove that much of the rainfall in what has 

 been known as the arid region, and where it was formerly supposed that 

 the precipitation was five inches or less, was not reported. In some of these 

 places the actual rainfall is as much as sixteen inches, and in one it is 

 thirty-seven. This explains why water is found so abundantly in wells in 

 some parts of Southern California, where the annual rainfall has been 

 reported as ten, twelve, and thirteen inches; the actual precipitation is 

 twenty-four inches. 



General Greely said that he had caused to be placed upon the charts the 

 maximum and the minimum rainfall of the various stations, not expecting 

 that they would indicate anything, but that the curves were almost as those 

 on the annual maps. He explained that the small average amount of rain- 

 fall formerly reported was due in part to the fact that so large a number of 

 stations had been situated along the line of the Pacific Railroad, which, 

 seeking low gradients, had been built through a section of country in which 

 the precipitation was small. He spoke also of the prevalent opinion that 

 the rainfall in the west is increasing, and said that he thinks this opinion 

 to be correct, and closed with the remark that it was not fair to treat that 

 country on the basis of seasonable rains, since the larger portion of the 

 precipitation took place during different months in different sections of 

 the region. 



In the brief discussion which followed the address, Professor G. K. Gil- 

 bert said it was not safe to fix any given amount of rainfall as the mini- 

 mum necessary for successful agriculture, without qualifications. Very 

 much depends upon the time when the rain falls, and the rapidity with 

 which evaporation takes place. More rain is required in Arizona than in 

 Dakota, and many unsuccessful agricultural experiments have been made 

 in Utah, near Camp Douglass, where the annual precipitation is as much 

 as eighteen inches. 



Professor Fernow said that he had compared the amount of rainfall 

 during the five months of vegetation, in Philadelphia, Buffalo, Dodge City, 

 and North Platte. It ranges from fifteen to seventeen inches, the largest 

 amount of precipitation being at North Platte. There was no lack of rain- 

 fall at the eastern stations, but at North Platte it was impossible to raise a 

 crop. He learned also from Utah that the amount of water needed to irri- 

 gate land there was less after two or three years than when it was first 

 turned on. 



Professor C. V. Riley spoke of the frequency and violence of the rainfall 

 as modifying in an important degree its effect. 



