IOWA ACADEMY OF SCIENCE 
190 
former of these waters, for example, containing less than 4 parts 
per million. 
Except in two waters from shallow wells, both probably highly 
polluted, all Iowa waters examined have been found to be acid to 
phenoltalein ; that is, they contain no normal carbonates. In 
many analyses by railroad chemists, however, considerable quan- 
tities of normal sodium carbonate are reported. In every case the 
waters analyzed have been found strongly alkaline to methyl-orange, 
which of course is not affected by carbonic acid. For these reasons, 
in practically all waters analyzed, the carbonates are regarded as 
acid carbonates and the acid ion is put down as HCO s when it is 
desired to represent the mineral matter as it actually exists in so- 
lution. Of course on evaporation approximately one-half of this 
ion is lost as C0 2 and H 2 0. 
There are in the state no highly carbonated waters such as those 
at Manitou and Saratoga. The ion HC0 2 rarely, if ever, exceeds 
700 parts per million and usually falls rather below half of that 
amount. No waters have been found highly charged with free 
carbon dioxide, and 25 parts per million may be regarded as about 
the maximum. It should be stated, however, that in transit from 
the wells to the laboratory there is much opportunity for the loss 
of the dissolved gas. 
When one attempts to formulate any general statements regard- 
ing the quality of deep well waters in different sections of the state 
and from different water-bearing strata, many complications are 
encountered. The difficulties are due to several causes which may 
be stated as follows : 
1. There are not yet sufficient data available. For instance, 
in the southwestern section of the state very few deep wells have 
been drilled. 
2. Except in the northeastern portion of the state deep wells 
receive water from more than one stratum, since the casings rarely 
go lower than about 1,000 feet. 
3. Casings are difficult to make water-tight, and it is probable 
that in the majority of instances the casings have either been de- 
fective from the beginning or they have been rusted through by the 
highly mineralized waters of especially the carboniferous. 
The problems of the relation of the quality of water to the geogra- 
phy and geology of the state have not yet been studied by the writer 
with any degree of thoroughness, and what is said below on this 
relationship is to be taken largely as tentative. 
