the human race thought of closing the
entrance to their huts; and no doubt the
first cunning hunter took lessons at the same
school in the art of spreading nets and snares
for his prey.

Amongst us of the human race, the divingbell
is a recent invention, but among spiders
it is as old as creation. Look into a large
glass globe filled with water, in which are
immerged several portions of aquatic vegetables,
some floating on the surface, and some
lying at the bottom. Amongst the blades of
grass and bits of reed, you will remark a sort
of purse, closely resembling in shape and size
the shell of a pigeon's egg, but pierced transversely
through the middle. It is filled with
air, and perfectly closed, except in its lower
part, where there is an aperture just sufficient
for the egress and ingress of a very small spider.
A strong and semi-transparent substance,
resembling white gauze, forms the texture of
the bell, firmly moored and anchored to the
submerged plants by threads and cables,
which hinder it from mounting to the surface.

M. Berthoud, the French naturalist, in
giving an account of these bell-divers, says,
he first discovered them in the ponds of
Gentilly, where they exist in great numbers,
but their habits have been long known.
"During the last week," adds that gentleman,
"I have been studying its habits."

Watch, he says, the lady coming out of her
retreat. Her length is about one eighth of an
inch, her body is brown, and on the upper part
of the back is drawn a dark patch, having four
little dots on its centre. This spider lives
under water, and yet requires air to breathe.
Her Maker has taught her how to solve a
problem which would have baffled the genius
of Newton. She swims on her back, and her
abdomen is enveloped in a bubble of air, which,
reflecting the prismatic colours, looks like
transparent mother-o'-pearl. She then rises to
the surface of the water, and elevates above
it the lower portion of her body; for, amongst
the arachnidae, the orifice of the organs of
respiration is placed in the abdomen. Once
on the surface, she breathes strongly, inhales
as much air as she possibly can; then she
gets beneath the water and gives out gently
the liquid particles with which her lungs
are gorged to excess; the long, silky, clammy
threads which cover her retain in its place
around her the bubble with which she is surrounded.
This done, she dives with precaution,
and carries into her nest—her divingbell—
a provision of air to replace what she
had consumed. When once ensconced in her
nest, she lies in ambush, with her cunning
little head lowered, watching for any prey
that may chance to pass. Woe to the tiny
worm that wriggles on the stalk near her
den! She darts forward, seizes him, and
bears him off to her bell of impermeable
gauze. While her habitation was in process
of making, and until it was finished, it was
naturally filled with water. But once the
work was ended, it became necessary to
expel the water, and replace it by atmospheric
air. In order to attain this end,
our spider had to make more than a
hundred trips to the surface. Each bubble
that she introduced into the bell, mounted
towards the top by its specific levity, displacing
an equal quantity of water, which was
forced out through the orifice below, until
at length the bell contained nothing but air.

Who knows whether the aquatic spider
may not have suggested to Fulton the idea of
constructing submarine boats, which were
first tried in 1804, at Rouen, and then at
Havre; and the following year in the Seine?
Yet the submarine vessel hardly yet is
complete. Until Dr. Payerne took the subject
in hand the other day,* the invention
of Fulton had scarcely advanced a step since
the death of its author; and man is still
inferior to the insect in the construction both
of the diving-bell and the submarine boat.

*  See page 76 of the present volume.

At the Cape of Good Hope there exists a
bird well known by the name of the Repubcan
Sparrow, and which is named in science,
Philoeterus Socius. This little creature builds
a regular square. With a number of its
congeners it takes possession of a tree, and
constructs around its summit an immense
nest, containing perhaps two hundred compartments.
Each has his own snug little
dwelling, where he lives with his wife, brings
up his family, and enjoys the most absolute
liberty. They are Communists so far as is
required for constructing their common
habitation, repairing it, defending it in case
of danger, and going in search of provisions.
Does any bird display an unsocial disobliging
disposition?— he is sure to be visited by a
select detachment of police, who turn him out
with merciless thrusts of their strong little
beaks, and never allow him to re-enter the
common precincts. Does some felonious
reptile try to wriggle in?—a civic guard is
formed instantly, and as soon as the vigilant
sentinel gives notice, the gallant troop sends
forth a shrill cry, hastens to reinforce the
regular garrison, and almost always forces
the enemy to retreat before a mass of
threatening beaks, which form a bristling
and impassable stockade.

Another bird, inhabiting the same locality,
constructs for himself a house consisting of
three apartments, with arched entrances like
those used in Roman architecture. This
bird, a species of heron, named Scopus umbretta,
builds his nest in a bush, or rather
around a bush, gives it a circular form, and
divides it into three compartments, communicating
with each other by means of
arched openings. He commences by setting
up the framework of his dwelling, profits
by the .branches which suit his plan, and
destroys those which come in his way; then
he seeks for the bits of stick needful to