bi-sulphuret of carbon, and obtained a ruby-
coloured liquid, in which metallic gold is so
minute that the particles are invisible by any
microscopic power. He satisfied himself that
the famous ancient ruby-stained glass owes its
colour to gold in a metallic state in extremest
division. By adding gelatine to the ruby
solution he made a ruby jelly precisely similar. We
might thus prepare "aurum potabile," drinkable
or eatable gold, if the old faith in its virtue
still subsisted. But what is this to the separation
of particles in the air which is left in the
receiver of an air-pump when pumping can go
no further, and which is far from being the
greatest degree of rarity which air is capable of
attaining? What is it to the division of
particles implied by the perfume of flowers
distributed and dispersed by air? One little
blossom, a lily of the valley, will scent a room;
a bunch of lilies of the valley, or a bouquet of
heliotrope, will make a large room unbearable
and untenable by many a person of not
otherwise feeble constitution. There are even
flowers that are scentless, as far as our
olfactory organs can perceive, which give out
emanations causing headache, if kept in
apartments. And what, again, is this to the scented
clue which the swift-running hare leaves on the
grass, enabling the keen-nosed hound to track
all his labyrinthine windings and doublings?
As Mr. Smee says, the human nose is literally
only a rudimentary organ when compared with
the olfactory nerves of several other animals. As
to smells, we are in the same position as the man
born blind, who can only receive his ideas of light
through the medium of the eyes of others.

Water supports both the largest and the
smallest living creatures which people the globe.
The monstrous whale revels in the ocean, the
microscopic monad in the pool and the ditch.
The inhabitants of air, like those of land, have
their stature confined within far narrower limits.
What is the bulk of the elephant, compared
with that of the larger cetaceans? What is the
smallness of the smallest quadruped, compared
with the minuteness of the rotifer? which yet
is comparatively large, for it is often visible by
the unassisted eye. The difference in the
respective sizes of insects, of bats, and of birds, is
still less wide than in that of quadrupeds. The
very smallest gnats, flies, and moths, are known
and perceptible. The air contains no aerial
infusoria, no animalcules which float or fly in air,
as they swim in water. The microscope has
revealed, in the air, nothing analogous to the
infinite multitude of smallest living creatures
with which stagnant waters teem. The dervish
who covered his mouth with a cloth, that he
might not destroy insect life when breathing,
but who unscrupulously drank water from Indian
tanks, took a troublesome precaution to mighty
little purpose.

Winds are air put in horizontal motion.
Their influence is most beneficial. Were there
no winds, the vapours that rise from the sea
would be returned back from the clouds, in
showers, to the very same places in the sea
whence they came. On an earth where no
winds blew, we should neither have green
pastures, still waters, nor running brooks. Air is
more liable to pollution and corruption than
water; stagnation is ruinous to it. Ceaseless
motion has been given to it; perpetual circulation
and intermingling of its ingredients are
required of it. The necessity of ventilation in
our buildings, the wholesome influences of fresh
air, are universally acknowledged. The cry in
cities for fresh air from the mountains or the
sea, reminds us continually of the life-giving
virtues of circulation.

It has been well said that the girdling
encircling air makes the whole world akin. It is the
laboratory for the whole animal and vegetable
kingdoms. The carbonic acid with which our
breathing fills the air to-day, to-morrow seeks
its way round the world. The date-trees that
grow round the falls of the Nile will drink it in
by their leaves; the cedars of Lebanon will
take of it to add to their stature. The oxygen
we are breathing now was distilled for us, some
short time ago, by the magnolias of the
Susquehanna, and the great trees that skirt the
Amazon. By the winds, superfluous water is
carried off and removed to other lands, where
its agency is required; or it is treasured up, as
the material of clouds, in the crystal vault of
the firmament, the source, when the fitting
season arrives, of the showers which provide for
the wants of the year.

The vertical motions of the air seem to be no
less important than its horizontal change of
place. The one, indeed, begets the other.
Upward and downward movements in fluids are
consequent upon each other, and they involve
lateral movements, that is, a true circulation.
The sea, with its vapour, is the great engine which
gives upward motion to the air. As soon as
aqueous vapour is formed, it rises. The air
resists its ascent; but it is lighter than the
air: it therefore forces the resisting particles of
air up along with it, and so produces ascending
columns in the atmosphere. The adjacent air
comes in to occupy the space which that carried
up by the vapour leaves behind it, and so there
is a horizontal current, or wind, produced.

For ages innumerable, Earth and Water have
offered to man the means of locomotion; will
Air ever yield the same? If we look to
probabilities only, the answer is not difficult.

Man seems to have been destined, from the
very first, gradually to become master of every
department and region of nature; and to urge
him to do so, out of sheer necessity, he was
started in life with few appliances— except his
intellect. His physical and material weakness
drives him to seek aid in every outward object.
With comparatively powerless teeth, claws, and
muscles, to protect him from an enemy, he was
forced to make to himself clubs, spears, bows and
arrows, and to invent gunpowder. Armed with
these, he can assume the offensive against the
tiger, the bear, and the elephant. His utmost
swiftness is sluggishness compared with that
of many other creatures, who yet do not fly; so