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In reality the column of water would be shorter, as we are
speaking of sea water, the density of which is greater than
that of fresh water. Very well, when you dive, Ned, as many
times 32 feet of water as there are above you, so many times
does your body bear a pressure equal to that of the atmosphere,
that is to say, 15 lb. for each square inch of its surface.
It follows, then, that at 320 feet this pressure equals
that of 10 atmospheres, of 100 atmospheres at 3,200 feet,
and of 1,000 atmospheres at 32,000 feet, that is, about 6 miles;
which is equivalent to saying that if you could attain this
depth in the ocean, each square three-eighths of an inch
of the surface of your body would bear a pressure of 5,600 lb.
Ah! my brave Ned, do you know how many square inches you carry on
the surface of your body?"
"I have no idea, Mr. Aronnax."
"About 6,500; and as in reality the atmospheric pressure is about 15 lb.
to the square inch, your 6,500 square inches bear at this moment a pressure
of 97,500 lb."
"Without my perceiving it?"
"Without your perceiving it. And if you are not crushed by
such a pressure, it is because the air penetrates the interior
of your body with equal pressure. Hence perfect equilibrium
between the interior and exterior pressure, which thus neutralise
each other, and which allows you to bear it without inconvenience.
But in the water it is another thing."
"Yes, I understand," replied Ned, becoming more attentive;
"because the water surrounds me, but does not penetrate."
"Precisely, Ned: so that at 32 feet beneath the surface of the sea you would
undergo a pressure of 97,500 lb.; at 320 feet, ten times that pressure;
at 3,200 feet, a hundred times that pressure; lastly, at 32,000 feet,
a thousand times that pressure would be 97,500,000 lb.--that is to say,
that you would be flattened as if you had been drawn from the plates of
a hydraulic machine!"
"The devil!" exclaimed Ned.
"Very well, my worthy harpooner, if some vertebrate, several hundred
yards long, and large in proportion, can maintain itself in such depths--
of those whose surface is represented by millions of square inches, that is
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