Feb. 2 ,1924 
Tissue Fluids in Cotton 
287 
These frequency distributions show two things: 
The values of all the physicochemical properties investigated show 
considerable variability from sample to sample. 
There are evidences of differences in the constants for the two parent 
forms and for the Fj hybrid. It is clear, however, that for an analysis 
of these differences we must turn to a more careful study of statistical 
constants. Since, however, the utmost precision is required we have 
determined the constants directly from the ungrouped data. These 
have been recorded to four significant figures in the case of A, to five 
significant, figures in the case of k and k/ A, and to three significant 
figures in the case of P H . These values are of course beyond the range 
of precision of the instruments employed, but they represent as close an 
approximation as it was possible to secure in the case of a single reading, 
and in the second series the results are, in practically all cases, the average 
of two readings. 
COMPARISON ON THE BASIS OP FREEZING POINT DEPRESSIONS 
The comparison between the various series of Pima Egyptian and 
Meade and Acala Upland cottons is made in Table X. Since all of the 
tables in which comparisons are drawn between the physicochemical 
properties of the Egyptian and Upland varieties are constructed in the 
same way, one explanation will suffice for those for k, k /A and P H 
(Tables XI to XIII), as well as for A. 
The varieties compared are given in column 1. For each variety two, 
and sometimes three, rows of plants are available. 12 By combining the 
Pima and Meade grown from self-fertilized and bulk seed respectively 
four rows are available for a comparison of Pima and Meade. In column 
2 are given the numbers of the rows from which the samples were taken. 
Two sets of constants are available for each variety. The upper entry 
represents in each case the constants derived from the first series of 
determinations (August 6 to 16) while the lower entry represents the 
constants derived from the second series of determinations (August 19 
to 27). Column 3 gives the number of individual determinations upon 
which the statistical constants are based. Column 4 indicates the series 
(i. e., the first or second collection) and the method of taking the differ¬ 
ences in drawing the comparison between the constants for the earlier 
and for the later period. Column 5 gives the average value of freezing- 
point depression for Egyptian cotton; column 6 gives the comparable 
value for Upland cotton. Column 7 gives the correlation coefficient 
measuring the relationship between the constants of the plants, or small 
groups of plants, grown in immediate association in the various duplets 
or triplets. The purpose of these coefficients will be discussed presently. 
Two sets of differences appear. 
The first set, entered opposite the row numbers in columns 8-10, show 
the differences between Egyptian and Upland cotton. The differences 
in column 8 are so taken that a positive sign indicates a greater freezing 
point depression in the Egyptian than in the Upland cotton. These 
constants are provided with probable errors, calculated by the equation 
given above (p. 279). Column 9 shows the ratio of these differences to 
their probable errors. 13 The differences as given in column 8 are absolute 
12 The location of these rows in the field will be clear from the map, fig. x, p. 372. 
13 These ratios have been calculated from the values of the differences and their probable errors carried 
to a larger number of places than can be given in the tables of this paper. They are, therefore, somewhat 
more accurate than those which may be recomputed from the values of the constants as given here. 
