THE EXHAUSTION OF THE ARABLE LANDS. 



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The preceding exhibit, covering twenty-two years of greatest expansion in American 

 agriculture, is divided into four periods, the lirst being seven years and eacli of the others 

 five. In the seven-year period, population is found to have increased 18.2 per cent, and 

 the cultivated area 20.2 per cent.; the drafts upon the arable lauds, in the shape of addi. 

 tiuus to the acreage in staple crops, amounting to 2,724,177 acres per annum, and 



