ds there are wonderful things to be seen
by the help of one of these glasses.

If you dropped a stone overboard here it would sink and sink gradually
for about two miles, until it found a resting-place on a slimy bottom of
ooze in a strange dark place. You have a pretty good idea of what a mile
is from running in the school races; in imagination set it up on end,
and add another to it, and then think of that stone sinking that
distance into the grey water! Down there it must be quite dark, for the
mass of water above cuts off the sunlight like a black curtain. There
are many beasts living there, nevertheless; lobsters and other
shell-fish as well as fish, and in a great many cases those that have
been examined are found to have no eyes; it is probable that they have
lost their eyesight in the course of many generations, because it would
be no help to them in getting a living in those black depths. The
subject is not fully understood yet, because _some_ deep-sea fishes have
exceptionally good sight, but these may possibly live higher up in the
water, where there is a certain amount of glare, and then their eyes
would become sharpened by necessity.

[Illustration: DEEP-SEA FISH.]

The bed of the ocean is not a level plain; if you could see it emptied
of all water, you would discover that the land slopes down, sometimes
gradually and sometimes with terrific precipices from the shores, and
that at the mouths of great rivers there are great banks of mud brought
down by the current and piled up, making a fat living for innumerable
sea-creatures. But at the very bottom, in this carpet of slime, there
are no weeds, or as we might call them sea-vegetables, for they cannot
live altogether without light, so the creatures which have their home in
what to us would seem this cheerless, miserable retreat, must live on
one another. They are differently built from surface fish, because they
have always resting upon them the weight of an enormous pile of water.
Picture a pyramid of water two miles high resting on anybody. It would
crush him to atoms; but the fish and crustacea down there are used to
it, and fitted by nature to support it, and so, if they are brought up
to the surface by any means, they burst! In deep-sea trawling it is
quite a common occurrence to see fishes literally burst open, with their
eyes protruding from the sockets, and this annoys the fishermen, because
they are of no use for the market in that condition. It i