294 
Joumal of Agricultural Research 
Vol. XXVIII, No 3 
The water extracts were prepared by soaking 10 gm. of the dry fiber in 100 cc. 
of distilled water. After 24 hours’ immersion, 5 cc. of the extract was withdrawn 
and was made up to a volume of 50 cc. by the addition of distilled water. The 
electrical resistance of the diluted extract was then determined and from the 
resistance, corrected to a temperature of 60° F., the salt content was computed 
as a percentage of the original 10 gm. of dry fiber. 8 
The fiber used in preparing the extracts was then washed thoroughly with 
distilled water to remove all water soluble salts, dried and ashed and the weight 
of the ash was computed as a percentage of the dry weight of the fiber. 
From each of the subsamples which had not been leached, 10 gm. of dry fiber 
were ashed and the ash content of each subsample was computed as a per¬ 
centage of the dry fiber. * * * 4 
The results of the several determinations are given in Table I. 
Table I.— Water-soluble salts and ash in samples of cotton fiber , all values being 
given as percentages of the dry weight of the fiber 
Samples of fiber 
Water- 
soluble 
salts, 
comput¬ 
ed from 
electrical 
resistance 
Ash 
residues 
of water- 
washed 
samples 
Sums of 
values in 
columns 
1 and 2 
Ash 
residues 
of un¬ 
washed 
samples 
Volatile 
salts 
(values in 
column 3 
minus 
values in 
column 4) 
ARIZONA SAMPLES 
A.—Pima from open bolls. 
1. 57 
0.38 
1.95 
0.99 
0.96 
B.—Pima from unopen bolls, alkali soil. 
1.73 
.28 
2.01 
1.44 
.57 
C.—Pima from unopen bolls, good soil.. 
1.58 
.22 
1.80 
1.23 
.57 
D.—Sea Island from unopen bolls, good soil. 
1. 30 
.31 
1. 61 
1.05 
.56 
E—Meade from unopen bolls, good soil.... 
1.39 
.36 
1. 75 
1.33 
.42 
F.—Lone Star from unopen bolls, good|Soil. 
1.53 
.22 
1. 75 
1.03 
.72 
SOUTH CAROLINA SAMPLES 
G.—Sea Island from unopen bolls. 
1. 44 
.20 
1.64 
1.10 
.54 
H. —Meade from unopen bolls_ 
1.29 
.21 
1. 50 
Average of all samples. 
1.48 
.27 
1. 75 
1.17 
.62 
It is evident from the data given in Table I that, as grown on similar soil in 
Arizona, the salt content of the fiber of Pima cotton (Sample C) is not appre¬ 
ciably higher than that of Sea Island and Upland cottons (Samples D, E, F). 5 6 
Nor do Sea Island and Upland cottons (Samples D and E) grown on irrigated 
land in Arizona contain appreciably more salt than cotton of the same varieties 
(Samples G and H) grown in South Carolina. There is somewhat more salt 
in fiber of Pima cotton from a very salty field (Sample B) than in fiber of the 
same variety from good soil (Sample C). It is further shown that Pima fiber 
which has been exposed to dust (Sample A) did not have a higher salt content 
than fiber of the same variety from unopen bolls (Sample C). 
The data in Table I show that on the average 85 per cent of the total salts and 
ash in cotton fiber is water-soluble material, while 67 per cent is nonvolatile 
material. 
* The table used in computing the salt content from the electrical resistance, corrected to 60° F., is given 
by Davis, R. O. E., and Bryan, H., the electrical bridge for the determination of soluble 
salts in SOILS. U. S. Dept. Agr. Bur. Soils Bui. 61, p. 27-29. 1910. 
4 The writers are indebted for the ash determinations to J. W. McLane of the Office of Biophysical In¬ 
vestigations, Bureau of Plant Industry, U. S. Department of Agriculture. 
6 On the other hand, Harris and his associates have found the leaf tissue fluids to contain significantly 
higher quantities of total electrolytes and of chlorids in Pima Egyptian than in Upland cottons. 
Harris, J. A., and others, the tissue fluids of Egyptian and upland cottons and their fi hybrid. 
Jour. Agr. Research 27 : 267-328, illus. 
- Lawrence J. V., and Lawrence, Z. W. the chlorid content of the leaf tissue fluids 
of Egyptian and upland cottons. Jour. Agr. Research. [Not yet published.] 
