48 Dr. dobson’s Account of the Harmattan, 
fo as to make them appear whitifh, I recommended to Mr. 
norris the ufe of a good microfcope, as this might pofiibly 
difcover fomething concerning the nature of thefe particles. 
44 I was prevented,” fays Mr. norris, 46 by the bad ftate of 
44 my health from availing myfelf of the microfcope ; neither 
44 could I difcover any thing by the tafte, or by expofing plates 
44 covered thinly with melafles, for when I had dropped an acid 
44 or alkali into the water in which I had diflolved the melafles, 
44 nothing followed to enable me to judge of the nature 
44 of the particles. Surely they cannot be infe&s, or ani- 
44 malcuhe of infects ? for we have no appearance of any 
44 thing produced from the myriads of them which are depofited 
4 ^ on the earth. They do not flow far over the furface of the 
44 fea : at two or three miles diftance from the fhore the fog is 
44 not fo thick as on the beach ; and at four or five leagues dif- 
46 tance it is intire ly loft, though the Harmattan itlclf is plainly 
44 felt for ten or twelve leagues, and blows frefh enough to alter 
44 thecourfeof the current.” 
2. Extreme drynefs 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, 
deprived of its nouriihment, and ftinted in its growth, only 
appears to ripen, for it becomes yellow and dry, without 
acquiring 
