14 



Part III.— Statistical Farm Work. 



Page. 



Chapter XIII. The Crops and Climates of the United States 351 



Variability of results from plat experiments 353 



Effect of variations in method of cultivation and in quality of seed for 



different regions and years 355 



Effect of variations in dates of seeding and harvesting 358 



Brief summary of conclusions 363 



Part IT. 

 Chapter XIV. Authorities: 



Catalogue of periodicals and authors referred to 365 



General index _ - - - - . 377 



