During the magnificent evening of June 25--in other words, three weeks after our departure--the frigate lay abreast of Cabo Blanco, thirty miles to leeward of the coast of Patagonia. We had crossed the Tropic of Capricorn, and the Strait of Magellan opened less than 700 miles to the south. Before eight days were out, the Abraham Lincoln would plow the waves of the Pacific.

Seated on the afterdeck, Ned Land and I chatted about one thing and another, staring at that mysterious sea whose depths to this day are beyond the reach of human eyes. Quite naturally, I led our conversation around to the giant unicorn, and I weighed our expedition's various chances for success or failure. Then, seeing that Ned just let me talk without saying much himself, I pressed him more closely.

"Ned," I asked him, "how can you still doubt the reality of this cetacean we're after? Do you have any particular reasons for being so skeptical?"

The harpooner stared at me awhile before replying, slapped his broad forehead in one of his standard gestures, closed his eyes as if to collect himself, and finally said:

"Just maybe, Professor Aronnax."

"But Ned, you're a professional whaler, a man familiar with all the great marine mammals--your mind should easily accept this hypothesis of an enormous cetacean, and you ought to be the last one to doubt it under these circumstances!"

"That's just where you're mistaken, professor," Ned replied. "The common man may still believe in fabulous comets crossing outer space, or in prehistoric monsters living at the earth's core, but astronomers and geologists don't swallow such fairy tales. It's the same with whalers. I've chased plenty of cetaceans, I've harpooned a good number, I've killed several. But no matter how powerful and well armed they were, neither their tails or their tusks could puncture the sheet-iron plates of a steamer."

"Even so, Ned, people mention vessels that narwhale tusks have run clean through."

"Wooden ships maybe," the Canadian replied. "But I've never seen the like. So till I have proof to the contrary, I'll deny that baleen whales, sperm whales, or unicorns can do any such thing."

"Listen to me, Ned--"

"No, no, professor. I'll go along with anything you want except that. Some gigantic devilfish maybe . . . ?"

"Even less likely, Ned. The devilfish is merely a mollusk, and even this name hints at its semiliquid flesh, because it's Latin meaning soft one. The devilfish doesn't belong to the vertebrate branch, and even if it were 500 feet long, it would still be utterly harmless to ships like the Scotia or the Abraham Lincoln. Consequently, the feats of krakens or other monsters of that ilk must be relegated to the realm of fiction."

"So, Mr. Naturalist," Ned Land continued in a bantering tone, "you'll just keep on believing in the existence of some enormous cetacean . . . ?"

"Yes, Ned, I repeat it with a conviction backed by factual logic. I believe in the existence of a mammal with a powerful constitution, belonging to the vertebrate branch like baleen whales, sperm whales, or dolphins, and armed with a tusk made of horn that has tremendous penetrating power."

"Humph!" the harpooner put in, shaking his head with the attitude of a man who doesn't want to be convinced.

"Note well, my fine Canadian," I went on, "if such an animal exists, if it lives deep in the ocean, if it frequents the liquid strata located miles beneath the surface of the water, it needs to have a constitution so solid, it defies all comparison."

"And why this powerful constitution?" Ned asked.

"Because it takes incalculable strength just to live in those deep strata and withstand their pressure."

"Oh really?" Ned said, tipping me a wink.

"Oh really, and I can prove it to you with a few simple figures."

"Bosh!" Ned replied. "You can make figures do anything you want!"

"In business, Ned, but not in mathematics. Listen to me. Let's accept that the pressure of one atmosphere is represented by the pressure of a column of water thirty-two feet high. In reality, such a column of water wouldn't be quite so high because here we're dealing with salt water, which is denser than fresh water. Well then, when you dive under the waves, Ned, for every thirty-two feet of water above you, your body is tolerating the pressure of one more atmosphere, in other words, one more kilogram per each square centimeter on your body's surface.