andiwork, their principal mission in life seems to be warfare upon
the weaker creatures about them.

Upon their bodies are many short hairs that have the power of enclosing
and retaining a good-sized bubble of air. Thus the little boatman is well
supplied for each submarine trip, and he does not have to return to the
surface until all this storage air has been exhausted. In perfectly pure
water, however, these boatmen can remain almost indefinitely below the
surface, although it is not known how they obtain from the water the
oxygen which they usually take from the air.

All of these skaters and boatmen thrive in small aquariums, and if given
pieces of scraped meat will live in perfect health. Here is an alluring
opportunity for anyone to add to our knowledge of insect life; for the
most recent scientific books admit that we do not yet know the complete
life history of even one of these little brothers of the pond.

Clear and cool, clear and cool,
By laughing shallow, and dreaming pool;
Cool and clear, cool and clear,
By shining shingle, and foaming weir,
Charles Kingsley.

THE VICTORY OF THE NIGHTHAWK

The time is not far distant when the bottom of the sea will be the only
place where primeval wildness will not have been defiled or destroyed by
man. He may sail his ships above, he may peer downward, even dare to
descend a few feet in a suit of rubber or a submarine boat, or he may
scratch a tiny furrow for a few yards with a dredge: but that is all.

When that time comes, the animals and birds which survive will be only
those which have found a way to adapt themselves to man's encroaching,
all-pervading civilisation. The time was when our far-distant ancestors
had, year in and year out, to fight for very existence against the wild
creatures about them. They then gained the upper hand, and from that time
to the present the only question has been, how long the wild creatures of
the earth could hold out.

The wolf, the bison, the beaver fought the battle out at once to all but
the bitter end. The crow, the muskrat, the fox have more than held their
own, by reason of cunning, hiding or quickness of sight; but they cannot
hope for this to last. The English sparrow has won by sheer audacity; but
most to be admired are those creatures which have so changed their habits
that some product of man's invention serve