29 



sieve were used for the second class, which will "be referred 

 to hereafter as small seed. 



These two classes of seed were each separated further into 

 heavy and light kernels "by means of solutions of sodium nitrate. 

 Seed that sank in a solution of specific gravity 1.35 but floated 

 in a solution of 1.40 was used for the heavy, and those kernels 

 which floated in a solution of specific gravity 1.26 "but sank 

 in one of 1.20 were classed as the light. In this manner there 

 were four grades of seed obtained: large heavy, large light, 

 small heavy, and small light. 



The first plantings were made in the Agronomy green house 

 at Berkeley and ordinary nursery flats were used. Soil was pre- 

 pared "by taking surface soil, a clay adobe, from the field south 

 of Agriculture Hall and mixing it with about equal parts of 

 sane? . The seed v.as planted at a depth of about two inches in 

 three of the six flats used and at a depth of one inch in the 

 others. Each was planted with all of the claseee of seed ar- 

 ranged according to the following diagram in order to secure 

 results as nearly comparable as possible. 



aabcdad a- 5 large heavy 



babcdbc b large light 



cabcdcb c - small heavy 



dabcdda d = small light 



aabcdad 



babcdbc 



cabcdcb 



dabcdda 



The endosperms were removed two weeks later but by that 

 time it was found that practically ell of it had been used up 

 by the plants so there could be no results expected. 



But the effect of large and small and heavy and light 

 seed as such was noted in the following data taken from the 

 experiment: 



