16G OBSERVATIONS UN THE WINDS. 



allows of its being supported by tbe least agitated air, is particularly re- 

 markable on that part of the desert between the parallel of 22° and Senegal. 

 We have seen it at the distance of 15 miles, when the coast could scarcely 

 be seen at 9 miles. 



This dust, alluded to on pp. 99 — 100, is further remarked on at the end of 

 this volume ; by some it is considered to consist of fine ashes blown from 

 the regions of forest fires in the interior. 



(93.) Bemarks by Captain T. Boteler, of H.M.S. Hecla. — Between the 

 Isles de Los and Sierra Leone, the Harmattan Season sets in with 

 November, or about a month earlier than off the Gambia, and prevails 

 through December and part of January, but not quite constantly ; for 

 occasional intervals of clear weather, accompanied by the refreshing sea- 

 breezes from the N.W., sometimes afford a respite to its oppressive effects. 

 Nor does the Harmattan blow uniformly, either in the same direction, or 

 with the same strength; for it ranges through eight points of the compass, 

 from N.N.E. to E.S.E. ; and, however fiery at the commencement, declines, 

 after the first month, to a comparatively light breeze. 



The peculiar haze, which more or less envelopes the Coast of Africa at 

 all times, is at its maximum during the influence of the Harmattan ; and, 

 though partially dispersed by the Tornados and the rainy season, returns 

 with increased density when they cease. Strangers should, therefore, be 

 on their guard when estimating their distance from the land, as the decep- 

 tive effect of this haze makes it appear much farther off than it really is ; 

 for the contrast which the coast presents to the eye, in different states of 

 the atmosphere, is very great. In clear weather, the view of the fertile 

 shelving hills in the Isles de Los, the stupendous features of the distant 

 mountains, the plains covered with trees, and the beautiful little island of 

 Matacong (described hereafter), are highly interesting; while, in hazy 

 weather, nothing is visible but a low mangrove coast, enveloped in mist, 

 with an indistinct opening of a river here and there, or perhaps a column 

 of smoke rising from a native village. 



The rainy season continues for four months, from May to September ; 

 but the Tornados, which invariably accompany its commencement and 

 termination, generally cease between those periods. They blow from the 

 E.S.B., and with great fury : but they seldom last more than three hours. 

 The prevalent winds, during the rest of the rainy season, are from the 

 Southward and Westward, and are usually so light as to give way in the 

 afternoon to the N.W. sea-breeze. 



(94.) Mr. G. T. Carter, Administrator of the Colony of Gambia, in his 

 Report for 1888, states that the Harmattan usually sets in early in Decem- 

 ber, and is eagerly looked for ufter the airless, oppressive weather in 

 October and November. It is an exceedingly dry wind, and though cool 

 and bracing in the early morning, becomes hot under the influence of the 

 sun, as it slackens in the middle of the day. The Harmattan is an inter- 

 mittent wind blowing for a few days, being then succeeded by the refresh- 

 ing sea-breeze, which in its turn gives way to the Harmattan. This inter- 

 change usually lasts up to tbe middle of April, the month of February 

 being the time when the Harmattan is most prevalent. 



The months of July and October are decidedly the most unhealthy and 



