able to determine in part the
difficult problem of the track of the winds in their circuits. How is
this? you will say. Dust coming from one place surely cannot be
distinguishable from dust coming from another. To the ignorant man it
is not, but to the man of science it is. There are certain minute
animal productions called infusoria and organisms peculiar to each
portion of the globe. The expression is, the habitat of such infusoria
is such or such a place. These infusoria can only be distinguished by a
most powerful microscope. Professor Ehrenberg, who has devoted his
attention to the subject, has examined specimens of the dust which is
now falling on our decks. He found it composed of dry infusoria, the
forms of which are found not on an African desert, but in the south-east
trade-wind regions of South America."

"South America, father!" exclaimed Jerry, pointing with his hand to the
south-west. "How can those clouds of red dust come all the way out here
in the teeth of the north-east trade-wind?"

"What becomes of the north-east trade-wind when it reaches the end of
its journey, and where is that end think you, my boy?" asked Captain
Frankland. Jerry looked puzzled, and I had not a notion to give forth
on the subject. "I will try and explain the matter; but when you can
obtain a work, written by Lieutenant Maury, of the American navy, you
will comprehend the subject much better," said Captain Frankland.
"There are three calm regions or belts surrounding the globe--one under
the equator, and one in each hemisphere, under the tropics of Cancer and
Capricorn, which you have heard spoken of as the horse latitudes.
Between these two belts blow the north-east and south-east trade-winds,
meeting at the equatorial belt. Now, when they get there, instead of
causing a whirlwind, the excessive heat causes the particles of which
they are composed to expand and rise, gradually producing a calm. After
rising a certain height, they again commence moving round the globe.
Which course they took it was difficult to say, till we find these
clouds of red dust carried along in an upper region of the atmosphere
from south-west to north-east; for not only are they found here, but up
the Mediterranean and across Switzerland. They are raised into the
atmosphere probably by whirlwinds which occur during the vernal equinox,
which is the dry season, from the valley of the lower Orinoco. Thus,
had a label been attached to each p