Evening star. [volume] (Washington, D.C.) 1854-1972, 1886-05-04
The Inquiry by the House Committee
OF Appropriations.

CAPT HoxIE SHOWS THE DEFECTS OF THE
PRESENT METHOD OF CONSTRUCTING THE
TUNNEL-Ir SHOULD HAVE BEEN SUNK Low
Err TO HARD RoCK-FAULrY CHARACTER OF
THE LINING-coNcRErE THE BEST AND THK
LEAST EXPENSIVE MATERIAL FOR LINING.
Capt. r. L. Hoxie was examined to-day by the
subcommittee ofthe House appropriations COM
mittee having In charge the appropriation for
the water-works extension for this city. He
was called before the committee as an expert,
being the originator OF the plans for the
tension, and gave fuller explanation than he
could give in his letter, as TO how the work
ought to be conducted 50 as TO be more efiectual,
and at the same time, more economical His
statement occupied over two hours, and will be
continued tomorrow.
Ali the members of the subcommittee
Messrs. Wilson, La Fevre, McComas and Hen
derson-were present and paid the strictest
very closely. HIS statements were very clear,
ana MS arguments were supported by the best
authority: A very favorable impression was
made on the committee. Major Lydecker and
capt Symonds were present, but asked no
Capt Hoxie thinks that the present method
OF lining the tunnel must be discontinued, be-
cause IL will be fatal 10 the OF the work.
Inc increased cost OF the present method is of
secondary Importance. He thinks that no eN-
pense should be spared 10 insure efficiency and
permanence In the aqueduct extension. He
se.ected concrete for the lining OF the tunnel
after carefully considering the merits of every
other available material, because concrete gives
10 better advantage than any other the essen
tlal attributes OF large conduit for water under
heavy pressure-rigid resistance to internal
pressure, without which rupture is inevitable;
strength which may be adapted To every
quirement; impermeability and pernanence.
fortunately, the best material Is the cheapest.
The discrepancy between his original estimates
and the present deficiency estimates results,
mainly, from starting the tunnel before sound
rock had been reached, SO that ii is driven
largely through demoralized rock, and more
than half OF IL requires lining; from the sub
siltution OIL brick, at SI4 per cubic yard, Tor
concrete at SO per cubic yard, for the lining,
anu from an unnecessarily large excavation tor
inning. III appears that three Of the five shafts
reached sound rocl, and two were stopped in
demoralzed rock. 1t does not appear that amy
effort was made, 10y the use OF the diamond dull,
commonly used ioT exploring rock in mines. Ia
ascertain how much further these two shafts
must be sunk To reach sound rock, though IL II
reported OF every shalt that the rock Increased
IN hardness with the depth. The cost ri putting
the tunnel nifty feet lower would have been
about $4,000.
retaining water under heavy pressure. The
numerous joints are a source oi failure. The
brick shell, backed with dry stone, used in the
present method OF lining, gives neither resist
aace 10 rupture nor lmperIneaUi!itN under tile
heavy pressure 10 which Ia must be subjected.
All existing structures OF this character consist
Oh soiio masonry oi brick or concrete, with
rig "a resistance 10 Internal Pressure.
lie stated That hls public record i'm the Dis
tfict Oh Columbia would show that in It's most
lmportan; works. the system OF relieving sewers
not yet completed, he had advocated "A larger
factor OF safety than WAS thought necessary 10y
other engineers.