Evening star. [volume] (Washington, D.C.) 1854-1972, 1876-12-02

gutter of one street is not interrupted by the
crown of the other, and unless some means
Dc taken to prevent il the surface water will
pass the catch basin without entering, and
Will accumulate at some other point, when
the catch basin and their outlets will be re-
Quired to receive and discharge the drainage
OF two or more squares.
THE USE OF sELF-ACTING FLOOD VALVES
was recommended in my last annual report
for the protection OF private property against
the consequences OF an over-taxed sewer,
and particularly in the case of cellars below
or near tide-levpl, in which no other remedy
could be devised. The valve should be placed
at or near the building line to prevent the
entrance of water from the sewer into the
premises by means Of the house connection.
1t has been said that these automatic valves
are of uncertain action and liable to get out
of order, and the complaint appears to be
well founded in the case of all that have been
brought to my notice, which depend upon
gravity, the motion of a hinge, or the accu-
rate fitting of metal surface, for closing them.
But there was brought to my notice recently
device which impresses me favorably as a
successful solution OF the problem. A de-
scription is here given of this device, for
which patent has been applied.
1t is probable that the work VIII have TO be
resumed and continued on the
TIBER SEWER
until the principal sewers emptying into il
are free from accumulation of sand and clay,
ana until additional gravel pits are con-
stTucted at the nletS to arrest such matter
brought down by the branches Of this sewer.
A prompt r nOval of the deposits will be
the sewer system. question of growing
importance is that of the disposition to be
me de of the
NoXIoUs GASES GENERATED IN THE
No plan has yet been tried with the present
sewer system, but AFTER an examination of
the various methods incline to The opinion
that but one is practicable. The use of alb
sOTbents, or disinfectants. will do perhaps,
for special and limited application, like
the use of "a trap for local suppression.
way the gases generated in 100 miles
of sewer has rot the appearance of practical
bility. The copiouS admiXture of pure air
with these gases renders them innoXiOuS and
the difference of temperature between the
sewers and the external air, together with
the great diffusive power of the gases, which
are of slight density, afford the means of in
Producing air into the sewers and withdraw
ing the diluted gases. The failure heretofore
Of plans for Yentilating sewers seems to have
been due to the attempt 20 effect this in a
wholesale fashion, by means of chimneys
creating powerful draught. and from which
too much was expected. The draught was
created, but its influence lost within a small
area. The system which applies to the yenti-
lation of mine fails in It's application to
sewers, with their long lines Of slight sec
tonal area, and numerous openings into the
external air. The ventilation can probably
be effected by making use of every opening,
and taking advantage of the motion of the
ulated to some extent.
1t will be necessary tO.perforate the covers
OF The manhOles which are located at inter
walls of about $50 feet, and to apply some de-
vice for intercepting the gases in their mo-
ton through the sewers from the lowest to
the highest points, so as to obviate the pres
ent tendency OF these gases TO accumulate at
the upper extremities of the sewers. This
tendency is that of the gases in chimney
fue, the whole line of s,wer being an in
clined fiue, and il is probable that the simple
opening of the manhOles for the admission of
AIR, without any mechanical device for the
detection Of the gases into the mauhOleS,
would favor this tendency by the DETECTING
power in the direction Of the sewer of the
slightest descending current of heavy air.
Under the old corporation government
works the sewers constructed were at first
without means of ventilation. After the de-
slruction of one or two Of them by the expan-
sion of gases, the maI-hOle covers were per-
forated, and no further troubls was expert
enced. The best system now in use for the
PURIFICATION OF DWELLINGS
having sewer communications is neither by
absorption. disinfectantS, nor suppression OF
the gaSSeS by the admission of pure air. Ii is
suggested that this can be done by tapping
the sewer connections at the builling line.
With an abundantsupply of water there need
he no apprehension OF injury 10 the public
health, but then thorough ventilation should
be gradually effected and the Immediate
ventilation of all dwelling houses connected
with sewers should be enforced by approDrI-
ate legislation. There is no reason to appre-
bend any future difficulty in the removal of
sewage, by the Potomac river, after its dis
charge.
am still of the opinion that the main Tibar
sew - not al sufficient capacity 10 carry of
the water of such storms as may occur, and
II at aI overflow should be provided at the
Botanical gardens TO meet such an emergency
The outlet of this ever,
JAMES CREEK CANAL,
has been dredged 70 the.propOscd depth, and
the retaining walls completed as far as Y
street south. A tendency TO make fmme-
diate use of the canal for delivering
boat-lOads of stone, gravel, and sand, is d.
velOping, and suggest certain precautiOn.
The walls have an excess of strength for the
purpose contemplated, but are not signed
as wharf walls To sustain heavy loads. 1t
Will De well 10 fix line, say ~ feet, in .ide of
the base OF the wall, by and in which all such
heavy material must be deposited.
1t is probable that the use Of sections Of the
canal can be leased for wharf purposes npon
The condition that the lessee shall make such
provision for the security Of the wall and
shall guarantee its preservation.
The engineer renews the question of
WATER SUPPLY
at some length, commenting on the fact thai
the system being now under the control Of
two distinct officers-District and United
States-and owing TO the inadequate means
of supply and distribution, he suggests that
the whole matter be placed under one man
agement and recommended To Congress with
view OF providing means for carrying out
whatever plan that may be decided upon by
a board of competent engineers.
THE WORK OF TREE PLANTING
under the parking commission has been
continued during the past year. \
Alter referring to the fact that the pres
ent commission has served without compen-
SatloE Tor five years, says, "their success is,
i believe, unprecedented in the history of
tree planting in large cities and the credit of
the resulting Ornamentation of the District
belongs to them" - With the
working force at a minimum for the per
Torrance of current work il has not been
practicable to perform the necessary field
work in the preparation of the system of
grades for the cities of Washington and
Georgetown, which was contemplated at the
time OF my last annual report. In this con-
nection may properly be considered the great
need OF an accurate typographical survey of
the District as a basis for future improve
ments in the county. In the immediate vi
clnity of both Washington and Georgetown
dwellings are springing up rapidly, and sub
divisions OF large tracts of land in accord
ance with Individual caprice are creating Sc
rious obstacles to the
SYSTEMATIC EXTENSION OF THE STREETS
AND AVENUES
OF the two cities into the county. That such
extension is inevitable in the near future is
apparent from the present rate of growth. Ii
should be provided for at once by the prepa-
ration and adoption of Il detailed plan based
upon careful study of the typographical
features ofthe county. Such an assurance of
the permanency of the improvements in real
estate as would be given by the ratification
by Congress of such plan would probably
secure the investment OF much timid capital
which a change in grades OF the last few
years have driven from the District. This is
more than probable, because il is difficult TO