The evening times., 1896-02-20
TO CLARITY RIVER WATER
War Department Engineers Ex-
perimenting With Filters.
COL. ELLI0T'S LAST REPORT
Needs of Filtration Pointed Ont and
the Most Approved Systems De-
scribed-It Would Cost a Million to
Erect One OF sufficient Size for
Present Demands

II is generally believed that the construc-
tion OF filtering reservoir is the only
practicable way to clarity the water of
the Potomac rive used In Washington, and
the article upon the muddy Potomac water
yesterday in The Evening Times aroused
no little degree of interest among its readers
aud voiced the sentiments OF almost, if
not quite, the entire population OF the city.
1t is conceded on almost every side that
there is no other way In which all OF the
people can be spared from drinking So
luton of clay and water and bathing in
a fluid that leaves marks where 1t touches
! for several months in the year. Individual
filters, where cheap, have proven failures;
where expensive, they are luxuries the
masses cannot enjoy.
As mentioned in Tie article referred to
above, Capt. ID. a. GaiIlard of the Washing
ton AQueduct office fas been experiment
ing in his office with a model litter that
is now in use in many of TIE principal cities
| of Europe. Capt. GailIard's model is six
feet high. In the bottom is a layer of
gravel one foot in thickness; stratum OF
coarse sand o qualthickness licsabove this
with three feet of fine sand above that.
Over all is enc foot of water. The water
that comes out at the bottom of the filter
is from 2 to / 3 per cent clearer than when
| 1t entered at the top.
A STRIKING COMPARISON.
To slow how wonderful a clearing that
Is in so short a time it may be mentioned
that the aqucduct officials have n bottle
| of water sitting in the window cleared by
aluni 1t required three grains to less than
a quart, and took nine hours before all or
the sediment had settled to the bottom.
There was then coating of clay in the
bottom of the bottle one-sixteenth OF an
inch in thickness. The solution was SO
strong, however, that the water tasted of
the alum.
Under the present condition of affairs
water OF the Potomac that transplants por-
tions Of the farms of the alley OF the Shen-
andoal into the stomaChs of Washing
tonians is used about three days after it
enters the conduit at Great Falls. Attempts
have been made to better its condition by
permitting 1t TO stand for great lengths OF
time i'll the reservoirs. But IL will clarity
by natural precipitation in no rea sonable
length OF time.
That is the reason the water office people
have given up all hopes OF u better water
supply in that way and are now looking
about for a means of 0fclearing il at wholesale.
The plan now being experimental witiby
Capt. Gaillard has demonstrated in prac-
tical use its great value as a germ arrester
as well as its purifying qualifications. The
water used by the citizens OF Altoona during
the last cholera scourge in Europe was
filtered after this manner. Altoona is about
seven miles below Hamburg on the Elbe.
The latter city draws her water supply from
seven miles above her own limits. while AL
tona draws hers from about an equal
distance below her last suburb.
In this manner size gets the sewage
OF both Hamburg and herself, and it is
estimated that there are from 20, 900 to
10000 more bacteria per cubic cent?
meter at the source of her water supply
than there is At the head OF Hamburg's S
supply The latter city did not have the
filtering system when the plague broke
out in '92, and her record of cholera
cases was 26.31 to each /. 900 OF the popu-
latioD. In Altoona there were 3.S cases
to each 1000 people.
Col George II. Elliot. formerly in charge
of the aqueduct office, touched upon the
subject of filtration for this city long and
interestingly in his last annual report, made
in 1894.