330 
On Atmospheric Deposits 
We may now consider the case of dust asserted to be 
blown from the desert of Africa. 
The first instance is the occurrence of a shower of 
reddish dust which fell some years since upon ships near 
the coast of Bombay. It is not impossible that this 
might be conveyed by the wind from Arabia or Africa; 
but the particulars of the fact alluded to I have not been 
able to obtain. The deserts of Scinde and of Upper 
India could have as easily supplied it as the opposite 
shores of the Indian Ocean. 
A fact better established, but equally doubtful as to 
the cause, is stated to have occurred during the eruption 
of Etna, on the 16th of May, 1830. The outburst of 
the volcano is described as unexpected and very terrible; 
calcined stones and red cinders having been carried far 
into the country, and no less than eight villages having 
been destroyed. During this convulsion a violent wind 
blew from the south east. 
The next day the coast of Calabria, and all parts of 
Italy exposed to the wind, were found to be covered by a 
reddish dust like that which occurs in the neighbourhood 
of the mountain. At first the dust was generally— 
and is even now by some persons—attributed to the moun¬ 
tain ; but letters from Palermo stated that, as the dust 
was accumulated chiefly to the south, it could not pro¬ 
ceed from the mountain, and that further analysis con¬ 
tradicted its volcanic origin. I give the conclusion in 
the words of the reporter of the fact to Ferussac’s 
Bulletin;—“II est done probable que la poussiere 
rougeatre tombee en Italie a ete transportee des plaines 
sumed that the focal eruption was on a very great scale. The above 
facts bear upon another subject, that of elevation of coast lines and 
mountain chains, and are curious, independently of the present 
reference. 
