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       REFERENCES

      Ceram, C. W.: Gods, Graves, and Scholars, Alfred A. Knopf, Inc., New York, 1952.

      Cole, John S., and O. R. Mathews: Tillage, U.S. Dept. Agr. Yearbook, Soils and Men, 1938.

      Davidson, J. B., and L. W. Chase: Farm Machinery and Farm Motors, Orange Judd Publishing Company, Inc., New York, 1912.

      Ellis, L. W., and Edward A. Rumely: Power and the Plow, Doubleday and Company, Inc., New York, 1911.

      Field, C. G.: Do you Really Need to Plow? Country Gent., 123(3):35, 1953.

      Passmore, J. B.: The English Plough, Oxford University Press, New York, 1930.

      Rogin, Leo: The Introduction of Farm Machinery in Its Relation to the Productivity of Labor in the Agriculture of the United States during the Nineteenth Century, University of California Press, Berkeley, Calif., 1931.

       PROBLEMS

      1. Define tillage and give the purposes of tillage.

      2. Trace the history of the development of plows.

      3. Discuss the relationship of the plow to the progress of mankind.

      4. Discuss the requirements of good tillage practices.

      5. Discuss methods and effects of handling crop residues.

      6. Classify types of tillage equipment.

      ¹ I Kings XIX: 19.