CLIMATIC CHANGES IN THE PRAIRIE REGION. 303 



except by the infiltration of precipitated moisture, but there is not sufficient area 

 to furnish this well on the theory of infiltration of rain. At the time of the 

 spring freshets, caused by the melting of the snow in the mountains, this well 

 overflows, and when the period of the freshets has passed and the streams in that 

 region assume their normal level, the water of the well subsides until the next 

 season of freshets when the same phenomenon is presented, and thus keeps up 

 its intermittent character. The other phenomenon was witnessed by a friend, as 

 stated, in Chicago. In building one of the light- houses on the shore of Lake 

 Michigan, near that city, it became necessary to make the foundation of piles, 

 and, after the circular group had been placed in position and an attempt was 

 made to drive the last and center pile, it apparently broke through a crust or shell 

 and disappeared. A cord and plummet was sunk through the opening and a 

 swift running stream was discovered flowing into the lake. 



The writer's experience on the plains, west of the ninety-eighth meridian, 

 ten years ago, seemed to warrant the assertion, even then, that there was a larger 

 amount of humidity in the atmosphere of that region than a superficial observa- 

 tion would concede. Clouds formed every day, and in the summer, the most 

 decided indications of showers would present themselves, but would pass off 

 without precipitating their refreshing drops on the earnest earth, this phenomenon 

 proved sufficient moisture, but the conditions necessary to force precipitation 

 were absent. With the introduction of the plow, and the cultivation of crops 

 and forest plantations, a wonderful change has taken place ; now it is the rule, 

 where before it was the exception, for the clouds to precipitate their moisture, and 

 showers are frequent] then a storm could be seen forming, and " the rain, like a 

 curtain," suspended in mid-air, but rarely reaching the earth, re-vaporization ap- 

 parently arresting the shower on its course to the ground; now 7 this curious 

 meteorological scene is rarely witnessed in the settled area, and disappears as 

 civilization moves onward. 



The fact must not be overlooked that the mere breaking up of large areas 

 by the plow in the prairie region has been an effective agent in the phenomena 

 of climatic changes. The moisture, instead of being rapidly drained into the 

 ravines and water-courses, has sunk into the soil and furnished nourishment for 

 the new vegetation which shades the ground more perfectly than the grasses and 

 presents a larger surface for the condensation of the atmospheric humidity in the 

 form of dew. The reflection of heat has been modified and the floating moisture 

 has been attracted to the earth in the same manner as the electrical fluid is drawn 

 to a good conductor. When we consider how many square miles of territory are 

 each year turned over, we cannot but admit the truth of the belief that the dis- 

 turbance of the soil enters largely as a factor in the problem of ameliorating 

 causes. 



Extensive tree growth on the plains has unquestionably sensibly affected the 

 climate and brought about the varied phenomena attributed to the presence of 

 forests, and the argument of the possibilities of success in clothing the grassy 



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