THE HAEMATTAN. 165 



intense solar heat so soon as the storm is over, sends forth such noisome 

 vapours as are the occasion of putrid fevers and other diseases. 



On this coast, from the middle of February to the first week in March, 

 a wind up the coast, from S.S.W. to S.S.B., prevails for about three weeks. 

 The Tornado season embraces part of March, all April, and the greater 

 part of May, about twelve weeks altogether. The rainy season sets in at 

 the latter end of May, lasts all June, and till about the 20th of July, about 

 eight weeks. Hence, high winds and squalls, with very heavy rains, to 

 the middle of August, about three weeks. The rain ceases ; and then, for 

 the first three weeks in September, the weather is foggy and close, without 

 any breeze. From this time, for about six weeks, the wind blows fresh 

 down the coast ; the Tornados and Southerly winds then succeed, with 

 some rain, generally called the latter rains, lasting about four weeks, to 

 the beginning of December, when the Harmattan season commences. 



(92.) Bemarks on the Harmattan, by Baron Boussin. — Although the 

 winds from N.E. to N.W. prevail on the N.W. Coast of Africa during the 

 dry season, that is, from November to May, they are, nevertheless, occa- 

 sionally interrupted between the 1st of December and the 1st of February 

 by the land-wind, which blows from E.N.E. to E.S.E., and sometimes 

 with violence. 



It is this wind which the inhabitants of the country call the Harmattan. 

 It comes on at different periods in the above interval, and blows during 

 one, two, and sometimes five or six successive days. This continuance, 

 however, is rare, as it is generally interrupted by the sea-breezes, which 

 commence about noon, after a calm of one or two hours. These alternate 

 land and sea-breezes generally last till the end of February, when the usual 

 winds entirely prevail. The Harmattan, which passes over the most arid 

 country of the globe, is of an extremely dry nature, and would probably 

 become insupportable, were it not frequently allayed by the sea-breezes 

 above mentioned. Notwithstanding the salutary effect of these breezes, 

 the drought is astonishing, so long as the Harmattan lasts. Mankind is 

 inconvenienced ; vegetables suffer so much as to be nearly killed ; the sun 

 loses its brilliancy, and is only to be seen when near noon ; the sand, 

 brought with it from the desert, pervades the atmosphere, and prevents 

 objects from being distinguished at the distance of a quarter of a mile. 

 Nevertheless, the effect of the Harmattan is not really injurious to health ; 

 it is remarked that it even purifies the atmosphere, by destroying the 

 noxious vapours with which it is replete on the conclusion of the rainy 

 season. It is usually on the return of the Harmattan that recovery com- 

 mences from disorders which are incident to the climate. 



The fog which accompanies the Harmattan loses nothing of its density 

 when 9 miles out at sea. On the edge of the Bank of Arguin, which ig 

 30 miles from the land, it prevented our distinguishing the horizon during 

 three successive days. This state of the atmosphere is not permanent, but 

 varies with the winds which produce it ; and, in general, independent of the 

 Harmattan, the African Coast, from Cape Bojador to Cape Verde, is con- 

 tinually covered, during the whole dry season, with a white mist, which is 

 seen from the sea much sooner than the land, of which it is a sure indica- 

 tion. This mist, which is nothing but sand, the extreme fineness of which 



