The Cecil Whig. [volume] (Elkton, Md.) 1841-current, 1884-05-17
FILTER FOR DRINKING WATER.

lie Importance Oh having pure water
for drinking is oltener conceded than
distinctly realized. We admit that very
serious evils may result from the use of
water containing noXious organic SUBJ
stances. and thea go on drinking such
water till the mischief is done. and we
are made t. suffer the consequences of
our heedlessness. As a matter of fact, a
very small proportion of the water OBJ
tanned either from wells, cisterns or city
pipes is safe to drink without proper
filtration. But what is proper filtration?
This question is answered at some
length by DR.. Titus Munson Coan, in
Harper's Weekly, and his suggestions are
so valuable that we will give the sub
stance of them for the benefit of our
readers.
! The kind of filtration required for
drinking water he says, is both a me-
chanical and chemical process. 1t is
what is necessary, but what is seldom
properly accomplished in filter which
is intended to give pure drinking water.
In other words, the water needs to be
not only strained but aerated to make it
pure.
| For small house filters-and these are
the only ones that thus far are able to
accomplish the desired object fully
sand and gravel are the best materials.
Why? First, because filtration involves
straining, or the mechanical detention
and separation of such particles as can.
net pass through the interstices of the
litter. Second, because much more than
mechanical straining is required really to
purify the water. Such filtration means
1.-The minute subdivision of the water.
in the form of thin film, and its exposure
in this finely divided state, to the oxygen
OF the air that is entangled in the minute
interstces of the filter; the consequent
oxygenating of the organic impurities
that the water contains, and their trans
formation from noxious organic sub.
stances into harmless inorganic SUBJ
stances This is oxidizing filtration; it
is, in fact, burning up of the impuri-
ties in solution. But the burning is done
in water instead of in fire, and SLOWLY in
stead Of swiftly. And this oxidizinc or
aerating filtration can never be done rap.
idly"
The reason why sand is a good sub
stance for a filter, then. is because it
divides the contained water so infinitely.
y cubic yard of sand contains a certain
number OF particles of a given fineness;
the area of the surfaces of these particles
amounts to about 900 square yards. If
this cube of sand can hold ne-half its
bulk in water, each cubic foot of water
Will be difiused over surface OF about
l'o0 square feet. making a film of but
ll40 of an inch in thickness. In this
way the water is oxygenated, and this
alone is true chemical filtration,
In the construction of filter for do.
nestle use, the practical points are: To
use no filter of which every nook and
corner is not easily accessible; to avoid
flters Ill which substances that readily
breed animal life are used; and never
even to look at any filter which let's the
water run through in full stream, like
those toy affairs which are often offered
for sale, but are of no practical value
whatever as filters. A good serviceable
and Inexpensive filter on the other hand.
such as is frequently used in France, NAV
be constructed as follows:
a two gallon stone jar, rather tall and
narrow, makes the best container. A
key of about equal size will answer as
well, il it is kept constantly in use, SO
that the taste of the wood shall not get
into the water. Put in tin stop-cock
within an inch of the bottom, and a
little above this an earthenware plate
pierced with small holes like a sieve.
The conical shape of the jar or barrel
will keep this in place if it is properly
fitted. Upon this the tiltering sub
/ stances are laiu. FIRST clean dry. coarse
sand, or clean, dry, small mr. pebbles,
to the depth of one inch; then halt. .,rb
| layer of charcoal, broken up into small
Jumps; and then an inch layer of fine
sand. The whole will settle together
into layer some three inches thick.
Top off with pebbles as large as an egg,
TO prevent the water, when poured in,
from dispacing the filtering substances
below. The whole apparatus should be
snugly covered and two or three times
year the charcoal should be changed,
and the sand and pebbles thoroughly
washed and dried in the sunlight.
This apparatus, DR.. Coan says, will
supply household of ten or dozen
people with all the pure water they need.
1t is practical c)ntrivance, and one
that can be made to order without much
difficulty.
POETRY IN ILLINOIS.