So it follows that at 320 feet down, this pressure is equal to ten atmospheres, to 100 atmospheres at 3,200 feet, and to 1,000 atmospheres at 32,000 feet, that is, at about two and a half vertical leagues down. Which is tantamount to saying that if you could reach such a depth in the ocean, each square centimeter on your body's surface would be experiencing 1,000 kilograms of pressure. Now, my gallant Ned, do you know how many square centimeters you have on your bodily surface?"
"I haven't the foggiest notion, Professor Aronnax."
"As many as that?"
"Yes, and since the atmosphere's pressure actually weighs slightly more than one kilogram per square centimeter, your 17,000 square centimeters are tolerating 17,568 kilograms at this very moment."
"Without my noticing it?"
"Without your noticing it. And if you aren't crushed by so much pressure, it's because the air penetrates the interior of your body with equal pressure. When the inside and outside pressures are in perfect balance, they neutralize each other and allow you to tolerate them without discomfort. But in the water it's another story."
"Yes, I see," Ned replied, growing more interested. "Because the water surrounds me but doesn't penetrate me."
"Precisely, Ned. So at thirty-two feet beneath the surface of the sea, you'll undergo a pressure of 17,568 kilograms; at 320 feet, or ten times greater pressure, it's 175,680 kilograms; at 3,200 feet, or 100 times greater pressure, it's 1,756,800 kilograms; finally, at 32,000 feet, or 1,000 times greater pressure, it's 17,568,000 kilograms; in other words, you'd be squashed as flat as if you'd just been yanked from between the plates of a hydraulic press!"
"Fire and brimstone!" Ned put in.
"All right then, my fine harpooner, if vertebrates several hundred meters long and proportionate in bulk live at such depths, their surface areas make up millions of square centimeters, and the pressure they undergo must be assessed in billions of kilograms. Calculate, then, how much resistance of bone structure and strength of constitution they'd need in order to withstand such pressures!"
"They'd need to be manufactured," Ned Land replied, "from sheet-iron plates eight inches thick, like ironclad frigates."
"Right, Ned, and then picture the damage such a mass could inflict if it were launched with the speed of an express train against a ship's hull."
"Yes . . . indeed . . . maybe," the Canadian replied, staggered by these figures but still not willing to give in.
"Well, have I convinced you?"
"You've convinced me of one thing, Mr. Naturalist. That deep in the sea, such animals would need to be just as strong as you say-- if they exist."
"But if they don't exist, my stubborn harpooner, how do you explain the accident that happened to the Scotia?"
"It's maybe . . . ," Ned said, hesitating.
"Because . . . it just couldn't be true!" the Canadian replied, unconsciously echoing a famous catchphrase of the scientist Arago.
But this reply proved nothing, other than how bullheaded the harpooner could be. That day I pressed him no further. The Scotia's accident was undeniable. Its hole was real enough that it had to be plugged up, and I don't think a hole's existence can be more emphatically proven. Now then, this hole didn't make itself, and since it hadn't resulted from underwater rocks or underwater machines, it must have been caused by the perforating tool of some animal.
Now, for all the reasons put forward to this point, I believed that this animal was a member of the branch Vertebrata, class Mammalia, group Pisciforma, and finally, order Cetacea. As for the family in which it would be placed (baleen whale, sperm whale, or dolphin), the genus to which it belonged, and the species in which it would find its proper home, these questions had to be left for later. To answer them called for dissecting this unknown monster; to dissect it called for catching it; to catch it called for harpooning it-- which was Ned Land's business; to harpoon it called for sighting it-- which was the crew's business; and to sight it called for encountering it-- which was a chancy business.