3 2 4 
Journal of Agricultural Research 
Vol. XXVII, No. S 
more acid than those of the Meade parent. In short, the hybrid is 
intermediate in acidity between the two parental forms. 
The results for hydrogen-ion concentration are of particular interest 
since in respect to this physical constant the behavior of the hybrid is 
quite different from that in respect to osmotic concentration and specific 
electrical conductivity, both of which show values for the hybrid which 
are distinctly lower than those of either of the parent forms. 
Hydrogen-ion concentration is therefore in full agreement with the 
great majority of morphological characters (other than size) with respect 
to which the hybrid is intermediate between the two parent forms. 
The foregoing statements summarize the results as far as a com¬ 
parison of the two cottons and their F x hybrid is concerned. We now 
have to consider certain outstanding features of these series of con¬ 
stants as a whole. 
Conspicuous among these general features is the fact that practically 
all the constants differ in the two series of determinations, made earlier 
and later in the month of August. 
Both osmotic concentration as measured by the depression of the 
freezing point, A, and electrical conductivity, k, are lower in the second 
series of determinations than in the first, in the case of both hybrids and 
parents. The differences are relatively large, and clearly significant. 
The ratio of specific electrical conductivity to freezing-point depression, 
k / A, is on the average lower in the second series of determinations made 
on the parent forms, but higher in the second series made on the hybrids. 
The difference between the first and second series of determinations made 
on the hybrids is much larger than that between the first and second 
series made on the parent forms. The values of P H , measuring acidity 
in terms of hydrogen-ion concentration, are uniformly higher in the 
second than in the first series of determinations. Since higher values 
of F h indicate lower acidities it is clear that the concentration of the 
hydrogen ion is also lower in the second series. 
Thus the concentrations of total solutes (molecules and ions) of all 
ionized solutes and of the hydrogen ion are lower in the second than in 
the first series. The explanation of these changes must await further 
investigation. 
In its bearing on the problem of the differentiation of the two types of 
cotton it is perhaps significant that the second series, while showing 
absolutely lower values of osmotic concentration, specific electrical con¬ 
ductivity, and concentration of the hydrogen ion, shows uniformly a 
greater differentiation with respect to these variables. Thus the dif¬ 
ferentiation between the two types increases with the advance of the 
season. 
The direct and the cross correlations between the homologous samples 
of the first and second series of determinations have been discussed. It 
is shown that the relationships for the Egyptian is very different from 
that for the Upland and hybrid plants. The explanation of these dif¬ 
ferences must await further investigation. 
There is a significant positive correlation between the members of the 
same duplet or triplet (the plants or groups of plants of the two or three 
types immediately associated at the same station of the field). This 
indicates a large influence of soil salinity, or some other factor of sub¬ 
stratum heterogeneity, or an influence of variations in atmospheric 
conditions during the period throughout which the samples were taken. 
