Evening star., 1922-06-10

came with her father.
LTHERE is no need Cor me to
say anything about cais-
son disease to, you, gentle
men, or to you. Miss Tay-
lor." began Kennedy. 4 think you
all know how it is caused and good
deal about it already. But, to be
perfectly clear. | will say that there
are five things that must, above all
others, be looked after in tunnel
work-the air pressure. the amount
of carbon dioxide in the air, the
length of the shifts which the men
work, the state of health of the men
as near as physical examination can
determine 1t, and the raptdity with
air so as to prevent carelessness.
which may cause the bends.
II find" he continued. that the
air pressure is not too high Tor satc-
w Proper examinations f"r carbon
dioXide are made. and the amount III
the air is not excessive. The shifts
are not even as long as those pre-
scribed by the law. The medical IN
spectiou is quite adequate ana as TOT
the locks the rules are stringent.
\ look of relief crossed the face OF
Orton a. this commentator or ms
work, followed by puzzled EXPIRES
sion that plainly Indicated that ne
would like TO know what was the
natter. il all the crucial things were
right. ,,,
bends are still hitting the racn, ana
there is no telling when a IRE or 4
blowout may occur IN any OF t"t
eight headings that are now beng
pushed under the river. Quite often
the work has been delayed and the
tunnel partly or wholly Hooded.
Now. you know the theory OF the
bends. 1t is that air-moStiy the
nitrogen in the air-iS '">"i ped ~
the blood under the pressure IN
coming out of the air II the nitro
gen is not all eliminated it stays in
the blood and. as the pressure Is re-
duced. il expands. 1t is Just as "a
YOU take a bottle of charSeu water
and pull the cork suddenly. The gas
rises in big bubbles. Cork II aSal n
and the gas bubbles cease to rise and
finally disappear. If You make Il
pinhole in the cork the gas will es-
cape slowly. without bubble. You
must decohpress the human body
slowly. bv stages. to let the super
saturated blood give up its nitrogen
to the lungs. which can eliminate IT,
Otherwise these bubbles catch IN the
veins, and the result is severe pains
PARALYSIS and even death. Gentle
men. see that ! am just wasting
time telling YOU this. for YOU kho"
II all well. But consider.
Keunedv placed an empty Corked nasN
on the table THE others regarded II
curiously but l recalled having seen II
in the tunnel , ,,.,,,,,,,,.
"I collected some of the air from the
tunnel when I was down there TINS
morning. | have since aualyzed IT. me
quantity of carbon dioXide is approNi-
mately what it should be-not hisn
enough of itself to cause troubie, rd. nu5,
'I found something else In that air be-
side carbon dioXide."
Nitrogen? broke in Orton quickly.
leaning forward
"Of course it is constituent of air
But tlat is not what | mean.
Then. for heavens sake. what oid
YOU findo" asked Orton.
II found in this air" replied Kennedy,
"a very peculiar miXture-an explosive
mixture.
"Yes. lack. the blow-outs that you
have had at the end of the tunnel were
not blow-outs at all. properly speaking.
They were explosions"
We sat aghast at this revelation.
"And, furthermore" added Kennedy,
"I should. if l We're you, call back all
the men from the tunnel until the cause
, for the presence of this explosive mix
ture is discovered ard renledied.
Orton reached mechanically for the
telephone to give the order. but Taylor
laid his hand on his arm. One moment,
Orton," ne said Let's hear Prof Ken
nedy out. He may be mistaken, and
there is no use frightening the men, un-
til we are certain"
what
of flash oil is used to lubricate the ma
chinery?'
ut is $50 degree Fahrenheit flash
test" he answered tersely.
And are the pipes leading air down
into the tunnel perfectly straight"
Straight"
yes. straight-no joints. no rockets
where oil. moisture and gases can COL
lect." =. ,,,
with a sort of contemptuous defiance.
They were facing each other coldly,
siziug each other up. Like a skillful law
yer, Kennedy dropped that point for a
moment to take up a new line of attack
"CappS" he demanded, turning sud-
denly, why do you always call up
on the telephone and let some one
know when you are going down in
the tunnel and when you are coming
out?" c ,,,,,,,v
recovering his composure.
Walter" said Craig to me, quietly.
"go out in the outer office. Behind
the telephone switchboard you Will
find a small box which you saw me
carry in there this morning and con-
meet with the switchboard. Detach
the wires, as you saw me attach
them, and bring it here"
No one moved as l placed the box
on darfting table before them.
Craig opened it. Inside he disclosed
a large disc of thin steel. like those
used by some mechanical music
boxes, only without any perforations.
He connected the wires from the box
to sort of megaphone. Then he
started the disc revolving.
Out of the little megaphone horn,
sticking up like a miniature talking
machine. came a voice: Number,
please. Four four three o. Yorkville
Busy, I'll call you. Try them again.
Central Hello. hello. Central
Kennedy stopped the machine. 1t
must be further along on the disc.
he remarked. This, by the way. is
an instrument known as the telegra-