As well as being a mythic tale, Moby-Dick is a superb guide to oceanography

Anyone who has read Moby-Dick will recognise the moment, 32 chapters in, when their line of attention, hitherto slackly paying out, snags. Having spirited us briskly through Manhattan, New Bedford and Nantucket, and having flushed Ahab from his lair on to the deck of the Pequod, Herman Melville divagates into a disquisition on whale taxonomies. In Ahab’s Rolling Sea, Richard J. King asks: ‘What happens to the story if Melville had an editor who convinced him to just cut cetology?’

Melville might have died rich and the rest of us would be all the poorer. ‘Cetology,’ writes King, lodges ‘a bone in the reader’s throat’. But, here, Ishmael is transmogrified from ‘goofy greenhand’ to ‘scholar and survivor, who has lived this world of whaling, studied ships and now has something of his own to say about it’. Thus, Moby-Dick begins its bell-bottom-like flare to the ‘digressive girth’ that would doom it commercially and condemn it to this day to be more talked about than read, yet make it talked about in the first place.