26 Colorado Experiment Station 
SOIL, HOOPER, COLORADO. SAMPLE DRIED AT 100° C. 
Percent 
Insoluble (sand) . 62.241 
Soluble silicic acid. 15.229 
Sulfuric acid . 0.362 
Phosphoric acid . 0.320 
Carbonic acid . 2.629 
Chlorin . 0.081 
Calcic oxid.•. 4.295 
Magnesic oxid . 1.595 
Potassic oxid . 1.383 
Sodic oxid .. 1.326 
Ferric oxid . 3.930 
Aluminic oxid . 4.259 
Manganic oxid (br) . 0.175 
Ignition. 2.260 
Sum . 100.085 
Oxygen equivalent to chlorin. 0.018 
Total .. 100.067 
These samples were collected in 1907. It is unfortunate that we 
cannot give the total solids present in these ground- and drain-waters 
but it can be stated that those from Sec. 24, T. 40, N., R. 8 E. were 
not remarkably rich, while those from the neighborhood of Mosca 
were quite rich. The drain-water from Sec. 24, T. 49 N., R. 8 E., 
however, is sufficiently rich in calcic sulfate to distinguish it from 
mountain waters though its other salts are very similar to the salts 
present in these. This is also a noticeable feature in the composition 
of the ground- and drain-waters previously given.. The waters, alka¬ 
lis, and soil extracts, so far given, with only one exception, are noor 
in chlorids. In this exception, the ground-water from Sec. 24. T. 40 
N., R. 8 E., the chlorin, calculated as sodic chlorid, amounts to 22.0 
percent of the total solids, which were not excessively abundant. 
WATERS ON EITHER SIDE OF RIVER DIFFER GREATLY FROM 
RIVER-WATER 
These data present the conditions existing on both sides of the 
Rio Grande up to 1908 and they reveal no such marked differences as 
one acquainted with the sections might expect. They are, however, 
consistent in one point, namely, they show that the waters, whether 
they are surface-, ground- or drain-waters, differ from the Rio Grande 
(waters in that they carry very greatly increased quantities of sulfates. 
The ground- and drain-waters of these sections differ from other 
ground- and drain-waters that we have studied in that they, in gen¬ 
eral, seem to carry the carbonates of the alkaline earths and an excess 
of silicic acid. This last feature is not for the moment the specific 
object of our study. The main point, in this part of our discussion, is 
that the character of the alkalis, the soil extracts, the ground- and 
