3 xo 
Journal of Agricultural Research 
Vol. XXVII, No. 5 
constants, these differences have been expressed as percentages of the 
average value of the first determination in Table XIX. In this table the 
percentages are calculated by using the actual value of the first constant 
as a base, except in the case of P H , where the deviation of the first constant 
from neutrality, taken as 6.86, has been used. 
A comparison between the first and second series is facilitated by deter¬ 
mining averages for all the differences for the same type of plants (Egyp¬ 
tian, Upland, or hybrid). In determining such averages the percentage 
differences for the individual subcultures may be used, but some correc¬ 
tion must be made (by weighting) for the differences in the size of the sub¬ 
cultures. The averages of the change from first to second series in Table 
XIX have been computed for the Egyptian and Upland plants by weight¬ 
ing the constants for rows i and 5 and for rows 3 and 7 by two and that 
for rows 2, 4, and 6 by three and taking 7 as N in the determinations of the 
average. The averages for the hybrids have been calculated without 
weighting. 
Table XIX. —Percentage difference in average value of constants for first and second 
series of determinations in Pima Egyptian , Meade and Acala Upland , and F x hybrid 
cotton , in 1921 
Type and variety of cotton and nature of seed planted. 
Rows. 
i 
Freezing- 
point de¬ 
pression, 
A 
Specific 
electrical 
conduc¬ 
tivity,* 
K 
Ratio of 
conduc¬ 
tivity to 
depres¬ 
sion, 
k/ A 
Hydro¬ 
gen-ion 
concen¬ 
tration, 
Ph 
Pima Egyptian from self-fertilized seed. 
Pima Egyptian from bulk seed. 
Pima Egyptian combined series. 
Pima Egyptian from bulk seed. 
Average... 
1, 5 
3 , 7 
i, 3 ,S ,7 
2,4,6 
- 7-41 
— 7*36 
- 7-44 
— 4 * 45 
— 7*84 
“ 7*57 
- 7 * 71 
-6. 39 
—0.60 
—. 16 
-.38 
-2.15 
+ 5*57 
+6. 85 
+6. 24 
+ 9 * *3 
-6. 16 
- 7 * 14 
-1.14 
+ 7 * 50 
Meade Upland from self-fertilized seed. 
Meade Upland from bulk seed. 
Meade Upland combined series. 
Acala Upland from bulk seed. 
Average. 
I, S 
3,7 
r* 3 , 5,7 
2,4,6 
— 10. 39 
— 11. 14 
— 10. 76 
~ 9 - 05 
-12.44 
— 12. 01 
— 12. 23 
— 11. 28 
-2.35 
-1.19 
— 1. 78 
-2. 68 
+ 7* 20 
+ 3 * 73 
+ 5. 10 
+ 9 - 05 
—10. 03 
— 11. 82 
— 2.16 
+6. 72 
Fj Hybrid between Egyptian and Upland. 
Do. 
i ,5 
3,7 
i* 3 , 5,7 
-12. 54 
-14. 70 
— 13. 60 
-8* 75 
— 12.13 
— 10. 42 
+ 3*95 
+3. 08 
+ 3*52 
+ 4 * 92 
+6. 21 
+ 5 * 54 
Do. 
Average... 
— 13*63 
-10.44 
+ 3*51 
+ 5*57 
Both osmotic concentration as measured by the depression of the 
freezing point, A, and specific electrical conductivity in reciprocal ohms, 
k , are lower in the second series than the first. The values of P H are 
higher in the second than in the first series, but since higher values of 
P H indicate lower concentrations of the hydrogen ion, it is clear that the 
concentration of the hydrogen ion is also lower in the second series than 
in the first. Thus the concentration of total solutes (molecules and ions), 
of all conducting solutes, and of hydrogen ions, is less in the second 
series than in the first. 
The ratio of specific electrical conductivity to freezing-point depres¬ 
sion is lower in the second series of determinations than in the first 
series for both Egyptian and Upland cottons, but the percentage differ¬ 
ences are small. Just the reverse is found in the hybrid. The explana¬ 
tion of these differences between the hybrids and the parent forms must 
await the results of further investigations. 
