The Democratic advocate. [volume] (Westminster, Md.) 1865-1972, 1893-02-18
THE WATER SUPPLY.
Distance from Which Impurities
Can Be Introduced.

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4 scientific experiment of great interest
and importance has been made ia Europe
to demonstrate from what distance impuri
ties can be carried by percolation through
the soil from a distant point upon its sur
face to a well from which a family supply
of water is obtained \ salt Of hthium,
which can readily be detected in water, was
sown upon plot of ground $50 feet from
well-a matter of twenty-seyen rods
The water from the well was daily exam
aned, and on the eighteenth day the un-
mistakable presence Of lithium was appar-
ent in the water Now p rods is long
distance from a well, as one counts distances
about his house, and yet in less than three
weeks substance from the surface of the
ground had been washed into the soil and
had been carried along the sloping, natural
drain pipes, if one may so speak of them,
that exist in the soil, and had thus found
its way into the water of the well.
There is an impression prevalent in some
quarters that even though impurities may
exist upon the surface of the earth about
ones premises, that all drainage from them
soaks directly down into the soil, and is
therefore rendered harmless. The expert
ment Just mentioned shows how utterly
untenable is this idea, and ought to set
those into earnest thought whose wells,
springs or other sources of water supply
are with in a possible area of pollution.
To understand how such pollution as has
been mentioned is possible, a knowledge of
the geological structure of soils from the
surface down to great depth is of import
ance. The soil of the earth, it is to be re-
membercd has been formed by the disin-
tegration of rock formations, which most
commonly existed in the form of layers,
laid down either in horizontal or an in
clined position. 1t is also to be remembered
that these layers differed greatly in charac-
ter A layer of sandstone may have oycr-
lain layer of SHE'LL so that as result of
disintegration we get layer of sandy soil
underlain by subsoil of clay. Many of
these layers are light and porous, and allow
water and solid matter in solution to pass
readily down through them. When, how
ever, this water, laden perhaps with i'm
purities reaches a layer more or less imper-
yious it is either held there ifthe impervious
layer forms somewhat of basin, or spreads
out in all directions if the layer is horizon
tai, or flows along its surface in one direc-
ton if the impervious layer is at all inclin-
ed-as it is quite sure to be, MS level for-
nations are comparatively rare.
Only investigation by cutting deeply
through the soil will show the exact nature
of the formation underlying the region
about ones house, but there are some sur
face indications that give considerable light
on the condition of things below the top
of the ground Sloping ground very com
monty indicates a bending down of the lay
ers or strata of which the soil is composed,
where the drainage from the stable could by
no possible means get to the well, while any
drainage from the house would naturally
be drawn off towards the barn. There are
few, if any surface indications ef what
may be the dangerous condition of the SOD
that is shown below the surface. There
all the drainage that soaks into the ground
about the barn and house will naturally
settle in the direction of the well, provided
one of the strata be somewhat impervious
to water. The danger Of such q situation
must be apparent. especially in the light of
the results obtained it the lithium expert
ment A depression between two eleva-
tions of ground indicates a basin-likc for
nation of the strata, which, if au impcr-
vious stratum is present, may carry the
drainage of the basin into any well that
may be situated in it.
A consideration of all these things shows
that unless intelligent care is exercised
either in the location Of wells or in the re-
moval of any possible source of contamina-
ton, the water supply may very readily
become source Of disease. and so consti-
tute perpetual menace to the health of
faniIy.