48 Dr. dobson’s Account of the Harmattan, 
fo as to make them appear whitifti, I recommended to Mn 
norris the ufe of a good microfcope, as this might poffibly 
difcover fomething concerning the nature of thefe particles. 
44 I was prevented,” fays Mr. norris, 44 by the bad bate of 
44 my health from availing myfelf of the microfcope ; neither 
■ 44 could I difcover any thing by the tafte, or by expofng plates 
44 covered thinly with melaffes, for when I had dropped an acid 
44 or alkali into the water in which I had diffolved the melaffes, 
44 nothing followed to enable me to judge of the nature 
44 of the particles. Surely they cannot be infedts, or ani- 
44 malcuke of infedts ? for we have no appearance of any 
44 thing produced from the myriads of them which aredepofited 
' 44 on the earth. They do not flow far over the furface of the 
■ fea : at two or three miles diftance from the fliore the fog is 
44 not fo thick as on the beach ; and at four or five leagues dif- 
44 tance it is intirely loft, though the Harmattan itfelf is plainly 
44 felt for ten or twelve leagues, and blows frefti enough to alter 
44 the courfe of the current.” 
2. Extreme drynefi makes another extraordinary property of 
; this wind. No dew falls during the continuance of the har- 
mattan; nor is there, the leaft appearance of moifture in the 
atmofphere. Vegetables of every kind are very much injured ; 
all tender plants, and moft of the productions of the garden, are 
deftroyed-,; the grafs withers, and becomes dry like hay; the 
vigorous ever-greens likewife feel its pernicious influence; the 
branches of the lemon, orange, and lime trees droop, the 
, leaves become flaccid, wither, and, if the harmattan continues 
to blow for ten or twelve days, are fo parched as to be eafily 
rubbed to duft between the fingers : the fruit of thefe trees, 
i deprived of its nourifhment, and Hinted in its growth, only 
• appears to ripen, for it becomes yellow and dry, without 
acquiring 
