are needed, no novel motive power is thought
of, not a new rope is required, not an extra
square yard of canvas is asked for—all that
is needed is a thorough knowledge of the
winds at sea, so that the navigator may, by
avoiding such of them as are adverse to him,
make use only of those which are in his
favour.

In so far as this practical, matter-of-fact
end is arrived at, the man of the world will of
course feel warmly interested in the inquiry.
But the sympathies of the student of science
are not less enlisted on the same side, for he
will by such means gather together many new
and beautiful facts serving to illustrate the
economy of Nature in some of her grandest
operations. Without a doubt it will be
through a knowledge of the world of winds
that we shall arrive at an understanding of
many phenomena at present but guessed at.
The course and duration of the air-currents
will explain the fertility or sterility of many
large tracts of country. The direction of the
winds will go far to account for the luxuriant
growth of particular plants in particular
localities. The winds will be found to be the great
ministers of good throughout the surface of
this globe, carrying on their invisible wings
precious gifts yielded up by Ocean to fertilize
and beautify the earth in far distant places,
and by a still wider and higher influence so
to equalise the ever-recurring disturbances
of temperature, moisture, electricity, as to
fit the world for the life and health of the
many species—animal and vegetable—which
exist upon its varied face.

"Fickle as the wind " is not an inapt adage,
when applied to the local character of the
winds. But looking at the general course of
the air-currents over the ocean, if we follow
the many wind-roads which stretch across
the deep, we shall see that, so far from
possessing any features of instability, the
circulation of the atmosphere about us is
fully as regular and well-defined, as are the
motions of the earth itself and the other
great bodies of our system. In fact, the
winds are a part of that wondrous and
beautiful whole which was called forth when "He
measured the waters in the hollow of his
hand, and comprehended the dust in a
measure, and weighed the mountains in scales
and the hills in the balance." Long before
modern science had told us anything concerning
atmospheric phenomena, an inspired
writer promulgated the whole system—
"The wind goeth towards the south, and
turneth about unto the north: it whirleth
about continually, and the wind returneth
again according to his circuits." This passage
really indicates what has been passing in
the world of winds since earth was created.
The aberrations of air-currents upon land
are but the eddies and offsets of the great
atmospheric tides caused by geological
irregularities, just as we find dead water and
whirlpools amidst the largest rivers.

The winds must no longer be regarded as
types of instability, but rather as ancient and
faithful chroniclers; we have but to consult
them intelligently to gather from them great
natural truths.

In order to learn the course of ocean
currents, investigators have long been in the
habit of casting into the sea, bottles, labelled
and marked, so that on these being found
cast ashore at remote places their course
might be made known to the world. What
man does with the waters Nature
accomplishes unasked with the air: she strangely
places tallies and marks upon the wings of
the wind in certain parts of the globe, by
which the philosophers in a distant country
may recognise the same wind, and so trace
it in its path over ocean and over land.

The sirocco, or African dust, which in spring
and autumn has long been observed falling
in the vicinity of the Cape de Verdes, Malta,
Genoa, Lyons, and the Tyrol, was believed to
have been brought from the great sandy
deserts of Africa by the prevailing winds
coming from that quarter, and the theory
appeared plausible enough. Men of science
were, however, not content to take this
supposition as it stood, and thanks to recent
improvements in the construction of
microscopes, one persevering philosopher,
Ehrenberg, has been enabled to ascertain
the precise nature and consequently the
original source of this supposed African
dust. His examinations have demonstrated
that this rain-dust does not belong to the
mineral, but to the vegetable kingdom; that
it consists not of earthy particles finely
divided, but of minute infusoria and organisms
whose habitat is not Africa, but South
America, and that too in the region of the
south-west trade winds. The professor was
not content with examining one specimen;
he compared the "rain-dust" gathered at
the Cape de Verdes with that collected at
Genoa, Lyons and Malta, and so closely
did they all resemble each other that they
might have been pronounced as taken from
one spot. Nay, more than this, one species
of infusoria, the eunotia amphyoxis, has
often been found in this dust with its green
ovaries, and therefore capable of life. That
this dust could not have come from Africa
is evident from its hue, which is red or
cinnamon colour, whereas the sands from
the great African deserts are all white or
greyish.

Carrying this inquiry still further we shall
by its means arrive at a key to the entire
system of atmospheric currents. We have
said that the rain-dust falls in the spring and
autumn: the actual time has been at periods
of thirty or forty days after the vernal and
autumnal equinoxes. It requires no argument
to demonstrate that these minute
particles of organic matter must have been
lifted from the surface of the earth, not.
during a rainy season, but at a period when