METHODS OF STUDYING AGRICULTURAL QUESTIONS 423 



grow older, it is true, however, that a smaller proportion of the 

 farmers of each age group were owners in 1900 than in 1890, 

 showing retardation in the movement from tenancy to free 

 ownership. The right hand illustration in Figure 17 shows the 

 reverse situation with regard to tenancy, that tenancy is most 

 common in the younger age groups and gradually declines. 

 A careful study of the facts now available shows that many 

 forces are in operation, some making for dependent tenants 

 others for independent landowning farmers. 



Another example of the historical study of economic forces is 

 afforded by the sheep industry in the United States. Between 

 1840 and 1850 there was a decline in the number of sheep kept in 

 parts of Vermont and in the eastern part of New York, but the 

 marked change was in Ohio and Michigan, where there was a 

 great increase. The tendencies were the same in Vermont, 

 New York, Ohio, and Michigan, between 1850 and 1860, with an 

 important beginning of the sheep industry in Texas, California, 

 and Oregon. 



The decade from 1860 to 1870 brought a reaction in north- 

 eastern Ohio and the beginnings of the concentration of the 

 sheep industry of Texas in the dry lands of the South. Both 

 of these movements continued during the next decade. By 

 1880, Vermont had almost ceased to be a sheep state, and the 

 sheep of New York were but a handful in comparison to the 

 number in 1840, but the beginnings of the new industry in the 

 Rocky Mountain states were already important in Colorado, 

 Wyoming, and Montana. During the next two decades the 

 development of the sheep industry in the mountain states con- 

 tinued, but between 1890 and 1900 a marked decline is shown in 

 California, Texas, Wisconsin, Michigan, and Ohio. 



When the maps for 1840 and 1910 are compared, it becomes 

 evident that during the seventy years the sheep industry made a 

 complete shift with the exception of a few counties in Pennsyl- 

 vania and Ohio, so far as the concentrated centers of production 

 are concerned. By reading the agricultural papers of this period 

 one finds many references to these changes. A well-known 

 Merino breeder of Vermont in one decade is heard from in the 



