No. 583] ON SUBSTBATUM HOMOGENEITY 449 



Table VII gives the first plot character, weighted fre- 

 quencies and empirical means for associated plots for 

 2 X 2-fold combinations from Montgomery's grain yield 

 data in wheat. 19 



The equation is 



For grain, g, g x = 218.993 + .603 g 1 . 

 The graph figures indicate sensible linearity. 



IV. Influence of Number of Ultimate Plots Combined 

 If an experimental field exhibit irregularities of condi- 

 tions which influence in a measurable degree the yield of 



TABLE VIII 



5 x 2-Fold Combination op Plots of rothamsted Wheat 

 The divisions of the field are indicated by the double vertical lines and 



41.11 j 42.51 I 40.32 I 38.53 I 36.65 



39.38 42.67 \ 38.25 j 39.66 38.51 



67.36 ! 78.49 ! 65.30 69.19 63.10 



