Definition of "corposant"

I said the corpusants have mercy on us all; and I hope they will, still. But do they only have mercy on long faces?--have they no bowels for a laugh? […] I take that mast-head flame we saw for a sign of good luck; for those masts are rooted in a hold that is going to be chock a' block with sperm-oil, d'ye see; and so, all that sperm will work up into the masts, like sap in a tree. Yes, our three masts will yet be as three spermaceti candles--that's the good promise we saw.

1851 November 14, Herman Melville, Moby-Dick; or, The Whale, 1st American edition, New York, N.Y.: Harper & Brothers; London: Richard Bentley, page 498

If there was a sharp point nearby, electricity would stream from it in a luminous brush, a little corposant, and one could blow out candles with the outstreaming “electric wind,” or even get this to turn a little rotor on its pivot.

2001, Oliver Sacks, Uncle Tungsten: Memories of a Chemical Boyhood