490 Philippine Journal of Science 1920 
and 20 are likewise lower than the corresponding minima for 
the two other series. For the low group the evidence is not 
so clear, but both minimum and maximum for series 16 are 
higher than the corresponding minima and maxima for series 
14 and 20. 
On the whole, it seems safe to conclude that the most promising 
solution for these young rice plants is to be looked for among 
solutions having total concentrations higher than the lowest and 
lower than the highest concentration here considered. For this 
reason attention will be mainly turned toward the series em- 
ploying the two medium total concentrations (series 15 and 16, 
and series 17 to 19). 
Before leaving the general subject of the comparison of the 
four different total concentrations, however, it may be remarked 
that both high and low yields are shown for all the triangles 
of the tetrahedral diagram (except the top one) for the lowest 
total concentration, but that the two groups become more and 
more sharply segregated with higher total concentrations, so 
that with the highest concentration (series 20) all the high 
values but one (T2R1S1, which has a comparatively low value 
for the high group) occur in the lowest triangle (T1), while no 
low values at all are shown for that triangle. This progressive 
segregation of the high values toward the lowest triangle of the 
diagram, with progressively higher total concentrations, may be 
considered to mean that the higher the total concentration the 
smaller must be the relative partial pressure of monopotassium 
phosphate, if excellent growth is to be expected. No segregation 
of this sort is apparent for series 14, with the lowest concentra- 
tion studied, and the distribution of the low and high top-yield 
values in this series fails to suggest any definite relation between 
salt proportions and these values. This fact, together with other 
data for series 14, seem to indicate that the total concentration 
is here too low to produce the best growth of these plants and 
to bring out their salt relations as has been mentioned. Omitting 
this series, we may observe that just two solutions (T1R1S1 and 
T1R2S1) gave high values in all the remaining series, SO that 
these two solutions appear, on the whole, to be most nearly 
balanced for these plants, for the whole range of total com 
centrations dealt with. ; 
Turning now to a special study of the solutions having medium 
total concentration (series 15 to 19), the upper part of Table © 
indicates that the low-medium was generally better suited to the 
production of top yields than was the high-medium total con- 
