280 Dr Knox on the Climate of Southern Africa . 
may, as a specimen, be mentioned the ports of Vera Cruz, the 
Bay of Honduras, Darien, St Juan, St Lucie, Trinidad, the 
mouths of the Orinooco, Surinam, and Demarara. In Africa, 
Senegal, Goree, Sierra Leone, and Benin. In the east are 
Ceylon, Sumatra, Borneo, and Batavia. I shall conclude these 
remarks, already perhaps too long, by an observation on a very 
interesting migratory bird, the Swallow. 
On the 21st November, in latitude 6 P 4' N., and longitude 
20° 31' W., we experienced those heavy squalls and rains, 
which, as has been already remarked, are uniformly met with 
in this climate. These storms are occasionally sublime, and 
worthy of a minute description. After the most perfect calm, 
heavy, dense, and gloomy clouds are seen collecting at every 
point of the horizon ; they form themselves into vast arches, ha- 
ving their abutments in the ocean ; suddenly at one point they 
blacken to an inky hue ; the sails are furled ; the crew stand 
in mute attention, each at his station, and every eye is direct- 
ed towards that vast and hideous mass of clouds, which, rest- 
ing on the surface of the deep, and reaching heaven with its 
top, advances upon the devoted vessel. Now, sweeping the 
ocean, it pours a deluge on the ship ; the storm rages, and, by 
the terrific force of the blast, the masts seem ready to start 
from the decks. When these squalls happen at night, and are 
attended with much rain, a ball of meteoric fire is seen at the 
mast-head, tending to increase the horrors of the storm. 
On the 21st, whilst beset on all sides by these squalls, a swal- 
low suddenly appeared close to the ship. There was no known 
land nearer than 300 miles ; the swallow was seen first during a 
calm, skimming round the vessel with great velocity and activi- 
ty, and seemed to feed abundantly on the flies which hovered 
round the ship’s sides. But during the squall which succeeded, 
its actions became those of self-preservation, and were admira- 
bly adapted to that purpose. As the rain poured in torrents, 
it beat down the swallow’s head in spite of all its efforts, thus 
interrupting its flight round the vessel. When the bird perceived 
this taking place, it rose perpendicularly through the air and 
dense rain ; fluttering moreover incessantly, and thus throwing 
to account for the absence of agues in the district of Lammer Muir , (about twenty 
miles south of Edinburgh,) since the cutting down, and destruction of the forests 
with which that country once abounded. 
