102 KANSAS ACADEMY OF SCIENCE. 



within the vast and almost unknown region of the "Treeless Plains" and the "Great 

 American Desert." During that brief intervening period, more than 1,000,000 people, 

 chiefly of the agricultural class, have taken possession of her domain, and have already 

 brought her to the very front rank of the States of the Union in the extent and value of 

 her agricultural products. History affords no other instance of the permanent occupa- 

 tion of so extensive an area previously unoccupied by man, by so large an agricultural 

 population in so short a space of time. Here certainly, if human agency could anywhere 

 affect climate, would such an effect be produced. Here, assuredly, if settlement ever in- 

 creases rainfall, will such increase be most marked and most unmistakable. That such 

 increase has actually taken place, I believe to be establisbed beyond a doubt. It is a 

 circumstance peculiarly favorable to the determination of the point in question, that 

 although 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 sufficient period to make possible a satisfactory comparison be- 

 tween the rainfall before settlement and after settlement. The records at Fort Leaven- 

 worth cover the longest period, and enable us to compare the nineteen years immediately 

 preceding the occupation of Kansas by white settlers with the nineteen years immedi- 

 ately 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 average increase of 5.21 

 inches per annum. Here we have an increase of nearly 20 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. Tbe 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 Signal 

 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 un- 

 doubtedly too short a period for either establishing or disproving the fact 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 Fort 

 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 notably greater than that of the first half. At Fort 

 Riley the increase amounts to 3.05 inches per annum, at Manhattan to 5.61 inches per 

 annum, and at Lawrence to 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 Fort 

 Riley, 13 per cent.; at Manhattan, 20 per cent.; and at Lawrence, over 9 per cent. If 

 this 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 results, 

 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 establish beyond doubt the fact of an increased 

 rainfall in the eastern half of Kansas. 



