Virginia citizen. (Irvington, Va.) 1891-1921, 1900-04-06
RISKS IN TuNNELlNG.
Mysterious Dangers 90 lie Encoun
tered While Uuder Ground.

Mysterious Dangers 60 he Encoun-
tered While Uuder Ground.
That there will soon be tunnels under
the East river To Brooklyn and TO South
Brooklyn seems to be assured. IL Is
possible. strange enough. to forecast
more closely what the engineers will
encounter under the bed Of the river
than what they will encounter under
the surface of Manhattan Island No
complete map exists OF the under
world OF the city. with its network of
sewers. coDduits, gas, steam and wa
ter mains, while some experience al
ready gained i'm work under the river
has placed I'm the possession of con-
tractors a pretty accurate idea of its
bed.
They have gained this despite the
heavy tides that make core borings
difficult or impossible. In the neigh
borhood of Blackwelrs island the cur
rent at spring tide sweeps up and
down the channel sometimes mt the
rate OF nine knots an hour The tide
runs with scarcely abated flow almost
to the turn. For only about 10 min
utes is there anything like still water.
and this is merely on top. The under
current runs later than the surface.
and while II may be still above the
tide will be running stronger at the
bottom.
The geological formation of the river
bed is accounted TO be the work of n
double glacier that flowed from the
Hudson valley 10y way of the Harlem,
and divided on the north end of Black
wells island. forming the channel on
either side. Under the channel Is an
almost solid bed of metamorphic rock.
On the New York side. in the neighbour
hood of Blackwells island. this is COM
paratively soft gneiss. Midway Il be-
comes hard and straight grained with
considerable mica. On the BROOKLYN
side 1t is massive and flinty as granite.
Decomposed feldspathic rock, soft as
cheese. is found. together with crystal
lied pyrites ana sections of carbonized
wood Near the Brooklyn side strata
OF rock have been encountered under
such pressure that at intervals they
gave forth sharp reports like the ex-
plosion of n pistol.
Experience has shown that perhaps
the greatest difficulties TO be met will
be those connected with the health of
the workmen. Toiling under the un-
natural air pressure which would be
needed whenever decomposed rock or
potholes of mud are discovered. the
men who will push the tunnels from
shore TO shore must face certain Dhys-
ical discomforts and some slight risks
OF strange and fatal maladies No per-
son having any disease of the bronchial
tubes, lungs or heart has any right to
enter pressure. Sudden death has
stricken down even the healthy in
working under the bed of the river.
The first Injurious effect of working
under pressure is an itching caused 10y
air globules In the capillaries. This
may he cured quickly by inducing pro-
fuse perspirntion. The next stage is
bends" an intense rheumatic pain I'm
the Joints caused by air globules in the
sockets. This may be benefited by sub
jecting the patient to a profuse perspi-
ration and removing him to n heated
pressure chamber. The last stage is
paralysis, frequently resulting in death.
or four men who died while digging
In the gas tunnel under the East river
the first expired half an hour after sue
cumbing 10 pressure and the second
before he could bc removed from the
tunnel. The third and fourth became
paralyzed from the shoulders down
and lived only n short time
Ii was found that hot black coffee.
provided in large quantities. was help
full TO the men. When the air pressure
did not exceed 30 pounds above that OF
the atmosphere, men were able to
work for nine hours. laying off one
hour In the middle OF the day.
Working under the highest prcssures.
they were unable Co remain In the un-
natural atmosphere with safety longer
than ~ hours. which. with an hours
rest between. made an actual days
work OF less than five hours-New
York Mail and ExDrcss