The missing chapter in Moby-Dick

Melville writes a long chapter in "Moby-Dick" about the whale's spout - what is it? water or vapor? - in which he goes into some detail about the whale's anatomy, his breathing and feeding, the principle of sounding, observations about how many spouts he exhumes while surfaced and so on, and Melville is extremely knowledgeable or so it seems but he misses one thing: as noted in earlier post, Melville had no idea that whales actually sang. He thought they had no voice, and made no utterance. Imagine if he'd known! Moby-Dick would be at least a hundred pages longer. That could be a great exercise for students: write the missing chapter of Moby-Dick, the song of the whale. What would Melville think, what would he do, whom would he compare the whale's song with, what would it mean for him? It is a strange concept, that their singing must be a form of communication, that there's a network of whales down in the deep - but their communication did not enable them to survive the hunt. Did it serve some other purpose, social or expressive? About mating or seeking sources of food? About currents and climates? I'm full of questions here, and maybe to some there are answers. There certainly must be answers to the question Melville raised about the nature of the spout, we must know today what the spout consists of: pure sea water, or is it mixed with some secretion from the whale? Whalemen thought it was poisonous, and some were injured in contact with it - could it have been vaporized and scalding? Or shot forth with such power that it could cause injury, like a fire hose? More questions.