KANSAS ACADEMY OF SCIENCE. 41 



sary to farm successfully in the State of Illinois, eastern Kansas, with its 

 better-drained soil, will furnish as much moisture to plant-life on twenty-five 

 inches of rainfall per annum, and western Kansas as much on a fall of twenty 

 inches; and if Illinois and eastern and western Kansas' had a like amount 

 of land under cultivation, I think the standard of suflBcient rainfall for each 

 would bear about the same relation to each other as the figures I have already 

 quoted, based upon the theory already advanced, that for the purposes of 

 comparison, the absorption and retentive qualities of the soil, and the amount 

 of rain utilized, rather than the amount that falls, shall be taken into con- 

 sideration. Had time permitted, I should have been pleased to show, by a 

 series of experiments with glass tubes filled with soil, the absorptive qualities 

 of the different varieties to which I have referred, and hope at some future 

 time to have an opportunity to do so. Perhaps some of our State institutions 

 will take this matter up, and give it a more thorough test than it would be 

 possible for me to do. 



By keeping in mind the peculiarities of our soil to which I have referred, 

 we can, I think, better understand why cultivation of the soil has so mate- 

 rially changed the climate of our State; and to this subject I wish now to 

 call your attention. 



The source of our water supply is mainly in the Gulf of Mexico. This 

 supply is transported hither in the form of aqueous vapor, by means of the 

 great aerial currents that flow northward from the gulf with so little variation 

 during the summer months, and here precipitated in the form of rain. Part 

 of this is received and stored in the soil for the use of plant life, part is re- 

 turned to the atmosphere by evaporation, and part is drained off" into the 

 streams, and carried back to the ocean, where it is again evaporated and 

 returned to us by the aerial currents. Thus our water supply is making a 

 continual circuit — flowing to the ocean as water, and returning therefrom 

 as vapor. 



As the wind currents are the mediums of conveyance of moisture from the 

 ocean to the land, a knowledge of the laws that govern their direction is an 

 important factor in the solution of our probable rain supply. 



The summer winds of Kansas are mainly southerly, those from the south- 

 east and south predominating over those from the southwest. 



During the winter season, the winds blow from all points of the compass, 

 the prevailing direction being from the west, northwest and north. The sum- 

 mer winds from the south are generally humid. The northerly and westerly 

 winds are generally dry. 



The steadiness of the wind breezes from the south during the summer 

 season may be attributed to two causes. One, the trade winds from the north- 

 east, flowing southwest toward the equator, south of the thirtieth parallel, 

 strike against the mountain chain of Central America, and are deflected to 

 the northwest, along the eastern slope of the mountains, and making a grand 

 curve, return over Kansas as a south or southwest wind. The other cause 



