Evening star. [volume] (Washington, D.C.) 1854-1972, 1892-01-16

The real increase in Warrington, II the presen,
prosperity OF our country continues, must b
much moro rapid"
This estimate is particularly interesting, a. 1,
shows to what an extent person may be RICH,
and wrong at the same time. All things con
sidered, Lieut. Meigs estimate Of population
was quite correct The city now has In the
neighborhood Of FAC, 600 inhabitants, and thil
number will be considerably added to in an
other year. 1t is safe to say that by February,
1893, Washington will fall little short Of $50 600
With his actual figures as basis il would seem
that the officer was something Of prophet .,
to population.
On the other hand the estimate Of thetotal con.
sumption Of water in 1893 was wholly wrong. The
city today consumes 4O, 000, 600 gallons Of water
each day, according to the most recent state
ments Of Col. Elliot. In another year il il al
together likely that the total consumption will
reach a, 000. 600, or twice 20 much AZ the esti.
mate put upon it by Lieut. Meigs forty years
ago. This error 10 interesting, Is showing how
the growth Of large cities has developed an I'M
expected increase in the common needs OF
water. That is TO say, Lieut.. Meigs, with all
his keenness in prediction, made apparent by
bis close calculation Of the future Of Washing
ton. was unable to grasp the vastness Of the
agency Of water as a civilizing medium.
Although his estimate Of the water demand
Of the future was but half large enough his
provision for the needs of the present day were
quite ample, a. our daily experiences seem to
show.
CALCULATIONS ABOUT THE SUPPLY.
Mentioning the great advantages to be de.
rived from good water supply, apparent in
the increased prosperity of q city possessing
such . supply, he remarks: 1.-THE quantity OF
water for daily use being determined. the next
question is what quantity should be stored in
reservoirs. This question admits Of no accu-
rate solution; the quantity will vary with the
nature OF the source and with the demand. II
the source is small, affordng little over the av-
erage daily supply. the reservoirs should be
larger than when, from an ample stream, an
increased quantity can be poured into them at
any moment to meet such contingencies a.
great contiagrations or great summer heats. If
the source is liable to fail entirely or in part
the reservoirs must contain enough not only
Tor the minimum daily use, but for these same
contingencies. which are most likely to occur
during long continued droughts, which dry up
the streams.
''if the source be like the Potomac, an un-
failing river, always giving an ample supply,
sun II Is liable to great floods, during which
the turbld and discolored waters should, if
possible, be excluded from the reservoirs,
which, in this case, should contain enough for
several days supply, until the swollen waters
have subsidized within their ordinary limits and
returned to their ordinary state of purity.
when river is the source the reservoirs
should be large enough to allow the water to
remain some time in them to deposit the
earthly and other insoluble matters mechani.
cally mixed with it, which Injuries its appear
ance far more than the more deleterious ill.,
gradients, which, being dissolved, do not
diminish its clearness''
In that last sentence Lieut.. Meigs hit upon
one OF the great questions Of the present day.
1t Will thus be seen that the officer undertook
to correct the error Of installing clear water
for pure water, and to condemn turbid wator
as being unfit to drink. The subject of filtra-
ton is also taken up in the report little later
on, after some figures are given of the storage
capacity of other cities
THE MATTER OF FILTRATION
Lieut. Meigs lived before the day of success
ful filtration systems that purified or rather
Clarified the water supplies Of whole cities, and
hence his remarks On the subject hardly applv
to the present day. Yet he showed great Keen
ness in Investigating the matter He saws:
The ordinary modes of filtration on a great
scale are founded upon the same principles as
the smallest domestic filters, in which sand. by
stralning the water through its interspaces.
removes the ingredients mechanically sus,
pended. and charcoal, by its chemical affinity.
takes up the organic matter dissolved. But the
dlficulties are much increased when, instead
OF Pints, the quantity to be filtered becomes
millions OF gallons. The filters, large and ex.