I May However
Add, That The Same Torn And Irregular Particles Of Gelatinous
Matter, Described By Ehrenberg, Seem In The Southern As
Well As In The Northern Hemisphere, To Be The Common Cause
Of This Phenomenon.
The particles were so minute as easily
to pass through fine gauze; yet many were distinctly visible
by the naked eye.
The water when placed in a tumbler and
agitated, gave out sparks, but a small portion in a watch-
glass scarcely ever was luminous. Ehrenberg states that
these particles all retain a certain degree of irritability. My
observations, some of which were made directly after taking
up the water, gave a different result. I may also mention,
that having used the net during one night, I allowed it to
become partially dry, and having occasion twelve hours
afterwards to employ it again, I found the whole surface
sparkled as brightly as when first taken out of the water.
It does not appear probable in this case, that the particles
could have remained so long alive. On one occasion having
kept a jelly-fish of the genus Dianaea till it was dead, the
water in which it was placed became luminous. When the
waves scintillate with bright green sparks, I believe it is
generally owing to minute crustacea. But there can be no
doubt that very many other pelagic animals, when alive, are
phosphorescent.
On two occasions I have observed the sea luminous at
considerable depths beneath the surface. Near the mouth
of the Plata some circular and oval patches, from two to
four yards in diameter, and with defined outlines, shone with
a steady but pale light; while the surrounding water only
gave out a few sparks.
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