Just as he had lain down he was surprised to observe the white pole of the staff flash into existence like a streak of phosphorus drawn downwards across the shade of night without.
In essence, over a period of time several ships had encountered " an enormous thing" at sea, a long spindle-shaped object, sometimes giving off a phosphorescent glow, infinitely bigger and faster than any whale.
MILKY-SEA PHENOMENON. Since the 17th century, sailors have reported encountering swaths of sea with a strange " milky" cast as far as the eye could see.
A phosphor is a substance that absorbs energy from another source, like a light for example, and then emits that energy as visible light, which is the glow we see.
Then it retreated two or three miles, leaving a phosphorescent trail comparable to those swirls of steam that shoot behind the locomotive of an express train.
From its glare and whiteness, I recognized the electric glow that had played around this underwater boat like some magnificent phosphorescent phenomenon.