IS THE RAINFALL OF KANSAS INCREASING ? 459 



nation of the point in question, that ahhough the general settlement of Kansas 

 by cultivators of the soil is of such recent date, reliable observations upon the 

 rainfall had been made at the military posts upon her eastern borders for a suffi- 

 cient period to make possible a satisfactory comparison between the rainfall before 

 settlement and after settlement. The records at Fort Leavenworth cover the 

 longest period and enable us to compare the nineteen years immediately preced- 

 ing the occupation of Kansas by white settlers, with the nineteen years immed- 

 iately following such occupation. During the first period the average rainfall 

 was 30.96 inches; during the second period it was 36.21 inches, giving an aver- 

 age increase of 5.21 inches per annum. Here we have an increase of nearly 25 

 per cent in the rainfall, under such conditions as to necessitate the inference that 

 such increase is chiefly, if not entirely, produced by causes connected with the 

 introduction upon a large scale of an agricultural population into a previously 

 uncultivated territory. The Fort Leavenworth records cover so long a period of 

 time (nearly forty years), that the increased average of the second half of the 

 period cannot be attributed to a mere " accidental variation." In the issue of 

 Science for April 18, 1884, it is stated that "the supposed increased rainfall in 

 the dry region beyond the Mississippi is not borne out by the returns of the Sig- 

 nal Service." But the records of the Signal Service, upon which this statement 

 was based, include a period of only twelve years of observation, from 1871 to 

 1882, which is undoubtedly too short a period for either establishing or disprov- 

 ing the faot of a " secular " variation. We have also called attention to the fact 

 that causes which have a tendency to secure an increased rainfall, have here been 

 put into operation upon a grander scale than in any other portion of the dry 

 region west of the Mississippi. 



But the fact of an increased Kansas rainfall does not rest entirely upon the 

 Fort Leavenworth observations. There are other stations in Kansas whose records 

 cover a much longer period than that of the longest established regular station of 

 the Signal Service. There are the twenty years' records of the United States 

 military post at Ft. Riley, the twenty-four years' records of the State Agricultural 

 College at Manhattan and the seventeen years' records of the State University at 

 Lawrence. If these several periods of observation be divided into two equal 

 parts, in each case it is found that the average rainfall of the second half is not- 

 ably greater than that of the first half. At Ft. Riley the increase amounts to 3.05 

 inches per anuum, and at Manhattan to 5.61 inches per annum and at Lawrence 

 at 3.06 inches. Expressed in per cent the rainfall of these three stations has 

 increased in the second half of each period of observation at Ft. Riley, 13 per 

 cent; at Manhattan, 20 per cent, and at Lawrence over 9 percent. If increased 

 rainfall could be shown by the records of a single station only, or if the several 

 stations, with sufficiently long periods of observation, exhibited discordant re- 

 sults, some indicating a decrease, while others indicated an increase ; or, if even 

 a single station indicated a diminished rainfall, the fact of a general increase 

 would lack satisfactory demonstration. But the entire agreement of the four 

 stations, whose records have value in a discussion of this question, seems to es- 



