IOWA ACADEMY OF SCIENCE 
193 
included in the series, but is the best available for the purpose. 
In the southwestern portion of the state, the region outside the 
territory of the above tables, there are strictly speaking no deep 
wells save those at Council Bluffs and Glenwood, both of which 
furnish very hard waters. 
The question is often asked whether the mineral content of a 
deep well changes with time and pumping. It would seem reason- 
able that the soluble mineral matter near the well might be dis- 
solved out to a marked degree and that the water would in conse- 
quence gradually become softer. In the early stages of my work 
on Iowa waters this problem was taken up and several old wells 
were analyzed and these analyses compared with those contained 
in Professor Norton’s Report. The effort in this direction was 
soon discontinued since it did not seem promising for several rea- 
sons. Some old analyses did not seem to be duly authenticated. 
Several wells had been deepened, partially filled, recased or aban- 
doned, and in others the casings had very possibly become inef- 
fective. 
Most of the analyses made agreed fairly well with the old anal- 
yses, though my analyses showed the mineral matter usually some- 
what smaller. This may have been due to more nearly complete 
dehydration of the residues obtained on evaporation. Further, 
there is reason to believe that new wells show higher solids before 
thorough pumping has removed the water in the immediate vicinity 
of the bore, and washed out the well. There are two striking 
exceptions to the general result. The older analysis from the well 
at West Liberty, carried out by Mr. Floyd Davis, shows twice the 
solids that I obtained; that is, 2,224 parts per million against my 
result, 1,066. In the water from the well at Nevada Mr. Briggs 
found 4,209 parts, while the recent analysis showed 2,368. 
The uncertainty of such comparisons and the difficulty also of 
arriving at a true estimate of the quality of water in any deep 
lying stratum are well illustrated in the history of the deep drillings 
at Grinnell. Well number (1) is 2,002 feet deep and was drilled 
in 1893. In Professor Norton’s report are the results of four 
analyses, made at different stages of the drilling, the last having 
been made at the end of the work. It shows 2,054 parts per 
million, and the other results are very nearly the same as this one. 
Considered as they stand there appears no great reason why the 
well should have been cased at all. As a matter of fact the casing 
was never effective, 
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