e great
marine mammalia--YOU ought to be the last to doubt under such
circumstances!"

"That is just what deceives you, Professor," replied Ned. "As a whaler
I have followed many a cetacean, harpooned a great number, and killed
several; but, however strong or well-armed they may have been, neither
their tails nor their weapons would have been able even to scratch the
iron plates of a steamer."

"But, Ned, they tell of ships which the teeth of the narwhal have
pierced through and through."

"Wooden ships--that is possible," replied the Canadian, "but I have
never seen it done; and, until further proof, I deny that whales,
cetaceans, or sea-unicorns could ever produce the effect you describe."

"Well, Ned, I repeat it with a conviction resting on the logic of
facts. I believe in the existence of a mammal power fully organised,
belonging to the branch of vertebrata, like the whales, the cachalots,
or the dolphins, and furnished with a horn of defence of great
penetrating power."

"Hum!" said the harpooner, shaking his head with the air of a man who
would not be convinced.

"Notice one thing, my worthy Canadian," I resumed. "If such an animal
is in existence, if it inhabits the depths of the ocean, if it
frequents the strata lying miles below the surface of the water, it
must necessarily possess an organisation the strength of which would
defy all comparison."

"And why this powerful organisation?" demanded Ned.

"Because it requires incalculable strength to keep one's self in these
strata and resist their pressure. Listen to me. Let us admit that the
pressure of the atmosphere is represented by the weight of a column of
water thirty-two feet high. 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 i