we had
reached what we considered the centre and shoalest part of the bank,
no bottom was found with a hundred fathoms of line. The peculiarity in
color was undoubtedly owing to luminous particles floating in the water,
and if we had remained on that spot until dark we should have seen that
whole tract of ocean splendidly illuminated.

The cause of this singular phenomenon has given rise to many theories
and much discussion among naturalists. It was for a time contended that
this phosphorescence was a quality of the water itself. But later and
more accurate observers ascertained beyond a doubt, that some marine
worms and other insects were luminous. On pursuing the investigation
it is ascertained that the sea water is far less pure than has been
supposed, and is often crowded with myriads of minute luminous animals.
It is now admitted that the phosphorescence of sea water is a property
not belonging to itself, but is produced by animalcula, or microscopic
creatures. They are far more numerous in some tracts of ocean than in
others, and all possess the power of producing a light, a spark, or
flash at will. There can be no doubt that these living, transparent
atoms cause the luminous appearance of the ocean, which excites
admiration, and has so often been described in glowing language by the
poet.

Chapter XXII. CAPTURED BY A PRIVATEER

Captain Moncrieff was desirous of entering the Caribbean Sea through the
Sail-rock passage, which separates the barren island of St. Thomas from
Porto Rico. But when we reached the latitude of those islands we beheld,
on our starboard bow, the mountainous country on the eastern part of
Hayti. The island of Porto Rico was soon afterwards seen on the other
bow, and directly ahead was the little island of Mona, rising abruptly
from the sea. Instead of striking the Sail-rock passage we found
ourselves in the centre of the Mona passage, a hundred and twenty miles
to leeward of Sail-rock, and twenty or thirty miles westward of the
meridian of LaGuayra.

Although Captain Moncrieff was glad of an opportunity to ascertain
his true position, he was mortified at finding himself westward of his
destined port. The Young Pilot was immediately hauled on a wind, and we
crossed the Caribbean Sea with a fine breeze, and one morning beheld
the Rocas, a cluster of barren rocks, right ahead. We passed over a bank
extending from this group of rocks, and with a fishing-line trailing
astern and a piec