While I do not know what they all mean, I can say that one thing that is evident is Melville's extreme care with the red pen. Let us look at this first page, Etymology, and at one entry on it, the entry for Webster's dictionary. Here is Melville's entry in the Etymology for Webster's, a book which may well have been in the homes of, and available for consultation by, most American readers of Moby Dick's first edition:
"WHALE. * * * Sw. and Dan. hval. This animal is named from roundness or rolling; for in Dan. hvalt is arched or vaulted.
Melville focuses on the Swedish and Danish word from Webster's. Here is the full entry in Webster's for the etymology (excluding the actual definition):
WHALE, n. [Sax. hwal, hwæl; G. wallfisch, from wallen, to: stir agitate, or rove; D. walvisch; Sw. and Dan. hval. This animal is named from roundness, or from rolling; for in Dan. hvalt is arched or vaulted; hvæller, to arch or vault, D. welven.]
Some of Melville's editorial omissions are supplanted by Melville's entry for Richardson's Dictionary:
WHALE. * * * It is more immediately from the Dut. and Ger. Wallen; A.A. Walw-ian, to roll, to wallow.
I know not exactly what Melville is doing here, but he's telling us half the story and setting up an argument between two etymologies where none exists. And he's getting me riled and argumentative before even introducing his first character (though I know he's likely gotten some others bored and confused).
What sort of dramatic tension is built up by this odd mix of humor, confusion and low dudgeon before the narrative even begins?
* Erromango, for those without intimate knowledge of the South Seas, is an Island that is now part of Vanatu, and lies about 500 miles due west of Fiji, with little but water in between.