776 Fluctuations 



2 and the regression 3. In other words the av- 

 erage of the progeny has gained over the aver- 

 age of the original variety slightly more than 

 one-third, and slightly less than one-half of the 

 parental deviation. I have repeated this exper- 

 iment of Fritz Miiller's and obtained nearly the 

 same regression of three-fifths, though working 

 with another variety, and under widely different 

 climatic conditions. 



The figures of Fritz Miiller were, as given be- 

 low, in one experiment. In the last column I 

 put the improvement calculated for a propor- 

 tion of two-fifths above the initial average of 12. 



Rows on Average of rows 12 + Ys of 



parent ears of progeny Difference 



14 12.6 12.8 



16 14.1 13.6 



18 15.2 14.4 



20 15.8 15.2 



22 16.1 16.0 



Galton, in his work on natural inheritance, 

 describes an experiment with the seeds of the 

 sweet pea or Lathyrus odoratus. He deter- 

 mined the average size in a lot of purchased 

 seeds, and selected groups of seeds of differ- 

 ent, but for each group constant, sizes. These 

 were sown, and the average of the seeds was 

 determined anew in the subsequent harvest they 

 yielded. These figures agreed with the rule of 

 Vilmorin and were calculated in the manner 



