On Falls of Dust on Vessels traversing the Atlantic. 135 
About a fortnight after the time when this ship crossed these 
parts of the Atlantic on her outward voyage, an analogous phe- 
nomenon was observed on board the English ship Roxburgh. 
One of the passengers, the Rey. W. B. Clarke, communicated 
the following notice of it to the Geological Society of London : 
—‘‘ On Tuesday, February 4, the latitude of the ship at noon 
was 14°31’ N., longitude 25°16’ W. The sky was overcast, 
and the weather thick and insufferably oppressive, though the 
thermometer was only 72°. At 3 p.m. the wind suddenly 
lulled into a calm, then rose from the 8.W., accompanied by 
rain ; and the air appeared to be filled with dust, which affected 
the eyes of the passengers and crew. At noon on the 5th of 
February, the latitude of the Roxburgh was 12°36’ N., longi- 
tude 24°13’ W.; the thermometer stood at 72°, and the baro- 
meter at 30°, the height which it had maintained during the 
voyage from England. The volcanic island of Fogo, one of 
the Cape de Verds, was about forty-five miles distant. The 
weather was clear and fine, but the sails were found to be 
covered with an impalpable reddish-brown powder, which, Mr 
Clarke states, resembled many of the varieties of ashes ejected 
from Vesuvius, and evidently was not sand blown from the 
African deserts.” 
Although Mr Clarke thus decidedly expresses himself against 
the sand-dust, yet the author of this notice is inclined to ascribe 
to it the phenomenon observed on board the Roxburgh ; for, 
had it been produced by volcanic ashes, we must have heard 
of a simultaneous eruption of the volcano of Fogo, but such was 
not the case. 
Mr Clarke also mentioned the following instances of similar 
phenomena, chiefly on the authority of the officers of the Rox- 
burgh :—“ In June 1822, the ship Kingston of Bristol, bound 
to Jamaica, while passing near Fogo, had her sails covered 
with a similar brownish powder, which, it is said, smelt strongly 
of sulphur. In the latitude of the Canaries, and longitude 
35° W., showers of ashes have been noticed two or three times. 
At Bombay, dust on one occasion fell on the decks of the ves- 
sels to the depth of an inch, and it was supposed to have been 
blown from Arabia, In January 1838, dust was noticed by 
the cr. w of a ship navigating the China Sea, and at a con- 
siderab.o distance from the Bashee islands, one of which had 
