436 FOOD SUPPLY PROBLEM 



7. WARREN, G. F.: "Elements of Agriculture." 13th edition, New York, 

 1913. 



8. CROOKES, SIR WILLIAM: "The Wheat Problem Based on Remarks 

 Made in the Presidential Address to the British Association at Bristol in 1898." 

 Revised. New York, 1900. Same, 3d Edition, with additional chapter. Lon- 

 don and New York, 1917. 



9. LIEBIG, JUSTUS: "Die Organische Chemie in ihrer Anwendung auf 

 Agrikultur, Chemie, und Physiologic," 1840. 



10. : "Die Chemische Prozess der Ernahrung der Vegetabilien." 



1862. 



11. : "Die Naturgesetze des Feldbaus, 1862. 



12. : "Agricultural Chemistry." 



13. CONRAD, J. LIEBIG'S: "Ansicht von der Bodenerschopfung und ihre 

 Geschichtliche, Statistische und Nationalokonomische Begriindung Kritisch 

 Gepruft." Jena, 1864. 



14. LYON, FIPPIN AND BUCKMAN: "Soils, Their Properties and Manage- 

 ment." New York, 1915. 



15. PARKER: "Field Management and Crop Rotation." St. Paul. 



16. RUSSELL AND HASTINGS: "Agricultural Bacteriology." Madison, 

 1915. 



17. STODDART, C. W.: "Chemistry of Agriculture." Philadelphia, 1915. 



18. "Rothamsted Memoirs." 



19. Bulletins: 1. "The Maintenance of Soil Fertility." A Quarter Cen- 

 tury's Work with Manure and Fertilizers. Ohio Agricultural Experiment 

 Station, Wooster, April, 1919, Bulletin 336. 2. "Commercial Fertilizers." 

 United States Department of Agriculture Farmers' Bulletin 222. 3. "Lime 

 and Clover." United States Department of Agriculture, Farmers Bulletin 237. 

 4. "Leguminous Crops for Green-manuring." United States Department of 

 Agriculture, Farmers' Bulletin 278. 5. "Renovation of Worn-Out Soils." 

 United States Department of Agriculture. Farmers' Bulletin 245. 6. "Bulle- 

 tins and Pamphlets issued (free) by Soil Improvement Committee of the 

 National Fertilizer Association, Postal Telegraph Bulletin," Chicago, 111. 

 7. "Bulletins of International Harvester Company of Chicago" (Agricultural 

 Extension Department). A large number of bulletins pertaining to soils 



20. Yearbook Department of Agriculture: 1912 CAMERON, FRANK K. 

 "Possible Source of Potash in the U. S.," 523-537. 1913 DAVIS, R. O. E. 

 "Economic Waste from Soil Erosion." 207-220. 1916 DANA, SAMUEL T. 

 "Farm, Forests and Erosion." 107-135. 1917 STINE, O. C.: "The World's 

 Supply of Wheat," 461-481. 



21. Spain "Problem of Provisioning and the Policy with Regard to the 

 Food Supply." International Review of Agricultural Economics, July, 1918, 

 585-603. 



22. HOPKINS, CYRIL G.: "Effect of Soil Depletion and Soil Enrichment 

 on Loan Values of Farms." Address delivered at Ninth Annual meeting of 

 Life Insurance Presidents, New York, Dec. 10, 1915. (Betterment of Life 

 Insurance Series.) 



