on Plant Growth in Nutrient Solutions , &c. 
37i 
previously found to be very efficient in maintaining the plants in a healthy 
condition without chlorosis in these solutions. Three cultures of the five in 
each of these two series producing high yields of tops and three producing 
high yields of roots are corresponding'cultures, and are included in the 
areas marking high yields in both series. The maximum yield of tops was 
produced by culture TjRgC, in series E and by culture T 1 R 1 C 5 in series F. 
The maximum yield of roots in each of the two series was produced by 
culture TgRjCg. 
A comparison of .the diagrams of Fig. 6 (series G, modified Tottingham 
Fig. 6 . Distribution of the highest five yields of soy bean tops and roots from the cultures of 
series G, supplied with ferric phosphate as the source of iron for the plants. Yields of tops 
represented by dotted areas, those of roots by stippled areas. 
solutions) with those of Figs. 4 and 5 shows the areas of high yields of both 
tops and roots on all three diagrams to occupy the same general positions 
at the bases of the several triangles. Three of the five cultures which 
produced high yields of tops and three of those which gave high root yields 
in each series are corresponding cultures, and are included in the yield areas 
on each of the three diagrams. The maximum yield of both tops and roots 
from the cultures containing ammonium sulphate (series G, Fig. 6 ) was 
produced by culture T 1 R 1 C 1 . 
The volume-molecular partial concentrations of the salts, and the 
ranges of these for the culture solutions which produced the highest five 
yields of tops and roots in each series, are given in Table VI, together with 
the absolute dry-weight yields produced. The maximum yields from each 
