CHAPTER XVI. 
Chalybeate (Iron) Group. 
The iron waters are usually carbonates, though the iron in 
some cases is regarded as a sulfate. Many of the waters here 
mentioned might very properly go in group IV as carbonates. 
Where there is only a small quantity of sulfate in the water 
it is evident that the iron has come from sandstones or similar 
rocks, and has been reduced by the organic matter which ac- 
companies the water in its course through the underground 
strata. Much of the soil contains an abundance of iron, and 
the waters, already charged with carbonic-acid gas holding 
calcium and magnesium salts in solution as bicarbonates, have 
only to come in contact with this iron and the rich vegetable 
mold to become in turn chalybeate waters. 
Many shales are filled with crystals of iron pyrites, and these, 
under the influence of air and moisture, especially in contact 
with organic matter, will oxidize, forming iron sulfate. Coal 
itself, or partially formed coal, as peat, is readily disintegrated 
by the action of the decomposing sulfids. Ordinary soft coal 
has but to be exposed to ‘‘weathering’’ to fall to pieces from 
this same cause. This gives us ‘‘mine water,’’ or, if shale 
which contains alumina has also been in contact with the de- 
composing material, an ‘‘alum water’’ is the result. It is evi- 
dent that the action of an iron-sulfate water, or an iron-chlorid 
water —both strong astringents— would be quite different from 
that of an iron-carbonate water. (See p. 55 for therapeutic ac- 
tion.) | | 
This group is represented by the following waters: 
Arrington, Atchison county, Nos. 1, 2, and 3. 
Atchison, McDuff’s spring. 
Atchison, Electric Light Company’s well. 
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