The Iola register., 1886-01-01
veoETAsLe DUST.

3As Sea Dust ef the Northers ssas shsvy
- Bs Particles Of Tropical Piaat La.
But the dust which constitutes Il.
chief part Of the red fog Of the Atlantic
the sea dust of the Northern seas, and
the sirocco-dust Of South Europe, /.
neither cosmic nor volcanic, though it
too. has travelled great distances.
Vessels, hundreds Of miles from land
have been at times evcloped for days in
. fog consisting Of briek-red or CHINA
mon-colored dust, which covered the
sails and rigging with thick coat, and
rendered the mir so hazy that NO vessel
which was more than q quarter of q
mile off could be distinguished even at
midday. OF St Jago. during certain
months of the year, q very fine dust is
almost constantly falling. which,
says Mr.. Darwin, roughens
and slightly Injuries sstro-
nomical instruments, hurts the ewes,
dirties everything on board. and at
times falls SO thickly that vessels have
been known to run ashore owing to the
obscurity, and are recommended to
avoid the passage between Cape Verd
and the Archipelago. Considerable
quantities continued to fall upon the
Beagle when she was between three and
four hundred miles from shore, some
of the variously colored transparent par
ticles beinga .housandth part of an
inch square, few larger, and the greater
part consisting of fine powder. On the
succeeding days. as the vessel proceed
ed on her way, the dust became SO fine
that it could be collected only on damp
sponge; but it has been known to fail
on vessels one thousand and even one
thousand six hundred miles from any
land.
From the direction of the wind and
the fact that the dust falls during those
months when the harmattan raises
clouds of it high in the air, and blows
from the northwest shores of Africa, it
was at first naturally concluded that the
dust Was all African too. The mineral
part of it, no doubt. may be so; but on
examination it was found that the great
part of the dust was organic, and con-
sisted mainly of those minute, flint
cased forms of plant-life known as di-
atoms, which exist in almost all water
salt, fresh, or brackish. Further exami-
nation also revealed the singular fact
that, though the dust came directly
from Africa, of all the many different
organic forms, none were peculiar to AZ
rica, and all but two belonged to
fresh-water families: and it has since
been proved that all the organic portion
of the dust, whether it fell at Cape
Verd, Malta, Genoa, Lyons or in the
Tyrol, has come from the south side Of
the equator, and has been transported
from the banks Of the OrinocO and
Amazon. When, however, we find that
particle Of mineral matter one-thou-
'andth part of an inch square can be
carried three or fonr hundred miles, and
that a narrow strip of vegetable sub
stance something more than half an
nch long, and the twelfth part of an
nch wide, clearly belonging to some
rOpical tree, has been carried more
han twelve hundred miles from any
,oast where it could have grown, we
wonder less at the long journeys taken
" these minute one-celled plants, A..
100, ,OOO, 900 of which occupy only one
'ubic inch of space. and weigh but
wo hundred and twenty grains.-From
The Worlds Lumber Room." by Selma
Jana