Cetology — Moby-Dick

Before the Pequod sails deeper into the endless ocean, Ishmael stops to explain whales. He says classifying whales is very hard. Famous scientists admit the subject is confused and full of gaps.

Many writers have written about whales, but few ever saw a living sperm whale. For centuries people praised the Greenland right whale as king of the sea. Ishmael says that time is over. The great sperm whale now reigns.

He will not try to write a perfect system. He says any human thing that claims to be complete must be faulty. He is only offering a rough draft.

First he settles a basic question. A whale is a fish, he says, and calls on Jonah to back him up. Whales have lungs and warm blood. His simple definition is this: a whale is a spouting fish with a horizontal tail.

Then he divides all whales into three big groups by size, like books on a shelf.

Book one is the Folio whales, the largest. These include the sperm whale, the right whale, the fin-back, the humpback, the razor back, and the sulphur bottom. The sperm whale is the biggest, most dangerous, and most valuable. The fin-back is shy and solitary. Some folio whales are barely known.

Book two is the Octavo whales, medium-sized. These include the grampus, black fish, narwhale, killer, and thrasher. The narwhale has a long horn. The killer attacks huge whales. The thrasher beats them with its tail.

Book three is the Duodecimo whales, the smallest. These are three kinds of porpoises. Even small porpoises count as whales because they spout and have horizontal tails.

Ishmael also lists rumored whales he knows only by sailor names. Then he stops on purpose.

He says his system is unfinished, like Cologne cathedral with a crane still on the tower. He does not want to finish it. This whole book, he says, is only the draft of a draft.