CURRENTS AND WHALING. 479 



the equator, is only affected by it at times, and Prince's Island is never 

 reached by it. The manner in which their climates are influenced by 

 this circumstance is thus described by Colonel Sabine: 



" The occasional advance of the cold water of the Equatorial Cur- 

 rent to the island of St. Thomas, may assist in explaining an apparent 

 peculiarity in the climate of that island, when compared with the 

 climate of the coast of Western Africa generally. At all the British 

 possessions, from the Gambia, in latitude 13° N., to the forts on the 

 Gold Coast, the months of June, July, and August, are accounted 

 unhealthy ; whilst at St. Thomas's, on the contrary, they are the most 

 healthy in the year to Europeans, although they are not so to the 

 negroes, who suffer much from colds and rheumatisms during their 

 continuance. It has been shown that the water of the Equatorial 

 Current is from ten to twelve degrees colder than that of the Gulf of 

 Guinea, and that its northern border, which at other seasons passes 

 the meridian of St. Thomas at a distance of from one hundred and 

 twenty to one hundred and eighty miles south of its southern extremity, 

 was found in June in contact, or very nearly so, with the island itself; 

 and it is not improbable, from a consideration of the causes which 

 occasion its advance towards the equator when the sun is in its 

 northern signs, that in July it may extend so far as even to include the 

 whole island of St. Thomas within its limits. 



" The temperature of the air is known to be immediately dependent 

 on that of the surface water of the sea, and to be influenced nearly to 

 the full extent of any alteration that may take place therein. In cross- 

 ing the Bight of Biafra, from Cape Formosa to St. Thomas's, the air, 

 over the surface of the Guinea Current, observed in the shade and to 

 windward, at sunrise, noon, and sunset, averaged 81 J°, the extremes 

 being 79° and 83^° ; whilst in the passage from the river Gaboon to 

 Ascension, over the Equatorial Current, the air averaged only 74°, the 

 extremes being from 73^° to 74^°, a part of the passage being, more- 

 over, on the very edge of the two currents, and within sight of St. 

 Thomas's. The vicinity of the Equatorial Current, therefore, when the 

 sun is in the northern signs, cannot fail materially to influence the 

 temperature of the island, (particularly as the wind is always from the 

 south,) and thus to affect its climate. Situated on the equator, St. 

 Thomas's has naturally two cold seasons, or winters, in the year, the 

 sun being equally distant in June and in December; but in June, July, 

 and August, is superadded the influence of the surface water of the 

 ocean, several degrees colder than in November, December, and 

 January ; rendering the months of June, July, and August, pre-eminently 

 the winter of St. Thomas's; in which the natives complain of colds 



