Mar. i, 1924 
Movement of Water in Irrigated Soils 
645 
It is doubtful if any useful purpose is served by reporting such analyses 
in terms of combined salts. The character of the solution may be in¬ 
dicated quite as clearly by reporting the quantities of the constituents 
identified as by reporting the theoretical combinations which are con¬ 
jectured. Furthermore, where the report includes only the elements or 
ions that have been identified it is less subject to misinterpretation than 
when it is given in terms of combined salts of which only one element 
or radical has been determined. The results of the analyses of certain 
underground waters are given in Table XII stated in parts per million. 
The figures in this table give all the facts that were actually determined 
in making the analyses. 
Table XII .—Composition of certain underground waters 
Sample No.« 
Total 
Constituents (parts per million). 
! Solids. 
Ca. 
Mg. 
HCOs. 
i 
i Cl. 
1 
SO*. 
I. 
1, 614 
*34 
i 
2 4 
249 
642 
211 
2. 
1,453 
203 
28 
163 
501 
2 59 
3 . 
534 
108 
16 
236 
n 5 
127 
4 . 
3 . 570 
80 
172 
0 279 
3 1 2 
1,920 
5 . 
9, 142 
555 
146 
5°4 
140 
5, 896 
5, 4oo 
408 
543 
549 
160 
2, 700 
7 . 
5.864 
270 
191 
43 2 
84 
3,427 
a The following is a description of the water samples: 
No. i. From wells tapping the underflow of the Gila River above Yuma, Ariz. 
No. 2, From wells used for irrigation on the south side of the Salt River Valley, Ariz. 
No. 3, From wells used for irrigation on the west side of the Salt River Valley, Ariz. 
No. 4, From a drain on the Newlands project, Nevada. 
No. 5, From a drain on the Shoshone project, Wyoming. 
No. 6, From a drain on the Belle Fourche project. South Dakota. 
No. 7, From a drain on the Huntley project, Montana. 
b Includes 48 parts per million normal carbonate. The other samples showed no reaction with phenol- 
phthalein. 
Where it is desired to make a comparison between several different 
samples of water as to the character of their dissolved constituents 
such comparison is greatly facilitated by stating the constituent in 
terms of percentage*of the total solids. In order not to have too many 
items for comparison, constituents having similar properties may be 
combined in the percentage statement. Thus the calcium and mag¬ 
nesium may be taken together and the carbonate and bicarbonate. 
In view of the fact that the bicarbonate radical (HC0 3 ) is monovalent 
while the carbonate radical (C0 3 ) is bivalent it is customary in com¬ 
bining them in the-percentage statement to divide the figure for the 
bicarbonate by 2 before making the addition. 
The combining weights of the bases and acids ordinarily found in 
irrigation and underground waters are such that the sum of the acids 
constitutes about two-thirds of the weight of the total solids. As a 
check on the accuracy of the analytical report, the percentage state¬ 
ment of the results may properly include an item for the total acids. 
If the figure for this item falls much above 70 or much below 60 the 
implication is that there has been an error in the work or that some 
other acid, possibly the nitrate radical, should be looked for. 
When the analysis of a water sample includes all the important bases, 
that is, the sodium and potassium as well as the calcium and magnesium, 
