eat
sheets thereon, and then rushing out upon the troubled waters of the
great deep, there, for days and nights, for weeks and months, and even
years, to brave the fury of the winds and waves, with nothing between us
and death except a wooden plank, some two or three inches thick!

It seems a bold thing for man to act in this fashion, even when he is
accustomed to it, and when he knows all about the sea which he sails
over; but when, like Cook, he knows very little about the far-off ocean
to which he is bound, his boldness seems and really is, much greater.
It is this very uncertainty, however, that charms the minds of
enterprising men, and gives interest to such voyages.

The Bible says, "They that go down to the sea in ships, that do business
in great waters; these see the works of the Lord, and His wonders in the
deep." Navigators in all ages have borne testimony to the truth of
this. The very first pages in Cook's journal mention some of these
wonders. He says that, while they were off the coast of Spain, Mr
Banks and Dr Solander, the naturalists, had an opportunity of observing
some very curious marine animals, some of which were like jelly, and so
colourless that it was difficult to see them in the water except at
night, when they became luminous, and glowed like pale liquid fire.
One, that was carefully examined, was about three inches long, and an
inch thick, with a hollow passing quite through it, and a brown spot at
one end, which was supposed to be its stomach. Four of these, when
first taken up out of the sea in a bucket, were found to be adhering
together, and were supposed to be one animal; but on being put into a
glass of water they separated and swam briskly about. Many of them
resembled precious stones, and shone in the water with bright and
beautiful colours. One little animal of this kind lived several hours
in a glass of salt water, swimming about with great agility, and at
every motion displaying a change of colours.

These _Medusae_, as they are called, have been spoken of by many
travellers, who tell us that in some parts of the sea they are so
numerous that the whole ocean is covered with them, and seems to be
composed of liquid fire, usually of a pale blue or green colour. The
appearance is described as being of great splendour. Even in the seas
on our own coasts this beautiful light is often seen. It is called
phosphoric light. Something of the same kind may be seen in the carcass