1920] SHU LL— SEEDS 37 1 



the data. Similar groups of data for 20 and 35 C. are shown in 



tables IV and V. 

 The absorpti( 



owing 



almost 



the seed. No attempt was made to carry out the work in so 

 detailed a manner as in the case of Xanthium seeds. Enough has 

 been done, however, to make it worth while to put the data on 

 record. The results with three named varieties of peas at the 

 three chosen temperatures are given in table VI. 



Mathematical discussion , 



For purposes of mathematical discussion it is not considered 

 essential to plot any curves of the data in addition to those given 

 in fig. 1. Only such curves are used as are necessary to an under- 

 standing of the discussion. Anyone desiring the curves can easily 

 plot them from the data. 



In view of the fact that Brown and Worley considered the 

 curves of water absorption in Hordeum seeds as paraboloid run- 

 ning out toward a common asymptote, attention was turned 

 first to the type of curve which would most nearly fit the 

 data shown in the preceding tables. Even a casual examination 

 of the data of tables I and II shows that the curves are not simple 

 ones. Since the situation is somewhat simpler in the case of 

 Xanthium seeds than in the split peas, the data from the former 

 will be considered first. 



Xanthium seeds 



ft 



During the first moments of absorption (40-60 seconds) the 

 entrance of water is exceedingly rapid; but in a short time the 

 rate breaks sharply to a lower rate, which then decreases slowly 

 but rather steadily during the main part of absorption, until 

 approaching saturation begins to affect the rapidity of intake. 

 In Xanthium seeds saturation occurs at about 50 per cent, and 

 the final break in the curve caused by approaching saturation 

 manifests itself at about 35-40 per cent, as is shown in the figures. 

 The whole curve is thus apparently a composite curve made 



