500 
Philippine Journal of Science 
1920 
third, and fourth triangles and the top apex of the whole tetra- 
hedron, and at the rear apex and the forward central region of 
the third triangle. The corresponding diagram for root yield 
(fig. 7) shows a high region near the forward right apex 
of the lowest triangle (much as for the lower total concentration 
in regard to both tops and roots) and it agrees with the diagram 
for tops in giving a high designation to solution T1R4S2 (which 
may be erratic here also) . The forward left apex of the second 
triangle is also indicated as of the high group, as in the case 
of the lower concentration and root yields (fig. 5). 
The low region of this root diagram (fig. 7) occupies the 
forward right apices of the second, third, and fourth triangles 
and the top apex of the tetrahedron as a whole. It differs from 
the corresponding top diagram (fig. 6) only in that the low 
region is not here extended beyond the forward right apex in 
the third triangle. 
With the higher of these two total concentrations it is again 
clear that top and root yields tend to be parallel, just as with 
the lower total concentration. 
Finally, it should be noted that two sets of salt proportions, 
TIRISI and T1R2S1, are shown as of the high group on all four 
diagrams. 
Study of the preceding pages and of the diagrams of figs. 4 
to 7 leads to the following guarded generalizations. It appears 
that solutions TlRlSl, T1R1S2, and T1R2S1 are to be regarded 
as having about the best salt proportions for the development 
of these plants, with the other conditions involved in these 
studies, and it similarly appears that solutions T1R1S5, T2R1S4, 
T3R1S3, T4R1S2, and T5R1S1 are to be regarded as very un- 
balanced and injurious. Under the given non-solution condi- 
tions and with total concentrations lying between 0.0016 and 
0.0038 gram-molecule per liter, these plants are found to give 
highest yields of both roots and tops when the culture solution 
contains relatively large proportions of magnesium sulphate, 
and relatively small proportions of the other three salts, them- 
selves present in nearly equal proportions. The three solutions 
just indicated as best have the salt proportions shown below: 
1 Solution No. 
KH 2 PO 4 . 
(NH4)2S04. 
Ca(NOs)2. 
MgS04. 
1 
1 TIRISI 
1 
1 
1 
6 
1 T1R1S2 - 
1 
1 
2 
4 
T1R2S1 
2 
4 
