Climate.
The growth of the foreign vegetation has been promoted by the mildness of the climate. Although lying in the torrid zone, St. Helena has 'no summer heats greater than those of England, the normal temperature being constantly lowered by the south-east breezes and cool waters of the Antarctic current, while the lower valleys are sheltered from the solar rays by the clouds settling on the encircling
hills. Throughout the year the days when the sky is overcast are twice as numerous as the cloudless days, and the mean difference between the winter colds and summer heats scarcely exceeds 30° F., the glass generally ranging from 53° F. to 83° F. For a hundred and forty days the annual rainfall reaches 27 inches in Jamestown, where the atmosphere is relatively dry; but at Longwood, in the hills, it exceeds 48 inches. Heavy downpours occur chiefly in March and April, that is, at the beginning of the Austral winter; but thunderstorms are
