( 134 ) 
On Falls of Dust on Vessels traversing the Atlantic. 
Tue west coast of Africa, between Cape Bojador and Cape 
Verd, and thence outwards, is, during the dry season, that is, 
from November to May, constantly enveloped in fog. This 
stratum, which was at an earlier period considered as the land 
itself, and is a sure sign of its proximity, consists of nothing 
else but dust or sand, which, on account of its extraordinary 
fineness, is raised into the atmosphere by the slightest current 
of air, and retained in a state of suspension. 
The projection of this sand, and its falling on ships which 
traverse the Atlantic Ocean at a considerable distance from 
Africa, is, it is true, a well known fact, but still, details are 
wanting as to the distance to which the sand of the African 
deserts can be carried; and the Journal kept on board the 
Prussian ship Princess Louisa contains instructive information 
on the subject. The phenomenon was observed both during 
the outward and the homeward voyage of the vessel, as the 
following abstract of a portion of the journal shews :— 
N. Lat. W. Long. Distance 
1839. from land. 
Jan. 14. 24°20’ 26°42’ Sails rendered quite yellow by sand, which 
had probably been brought from the coast 12° 
of Africa. 
— 15. 23°05’ 28°18’ Sails still yellower; when we struck the 
sails we found the colour was produced} do. 
by fine sand, which was thus loosened, 
May 6. 10°29’ 32°19’ Weremarked a yellow appearance on the 
sails like that seen during our outward * 17° 
voyage. 
— 7. 12°20’ 34°0’ The sails more yellow than they were yes- } 18° 
terday. 
— 8, 14°21’ 35°24’ Sails and ropes covered with yellow dust. 19° 
— 9. 16°44’ 36°37’ No increasing dust visible on the sails. 20° 
How we should be surprised if dust, which had been brought 
to us from Sahara, were to fall on the plains of Northern Ger- 
many, or if we heard that the ashes of a new eruption of 
/Stna had fallen at Copenhagen or Riga! These are distances 
which may be compared to those of the Princess Louisa from 
the coasts of Africa at the time when the sails were covered 
with Senigambian dust. 
