Chap, ii.] Moving Pillars of Sand. 467 



though in others it may be thought more analogous 

 to the firocco. It is called by Mr. Bruce the fimoom, 

 and from its effects-upon the lungs, I can entertain 

 but little doubt, that it confifts chiefly of carbonic acid 

 gas in a very denfe ftate, and perhaps mixed with fome 

 other noxious exhalations. 



In the fame defert Mr. Bruce obferved the afto- 

 nifhing phenomenon of moving pillars of fand *, 

 which are probably the effects of a number of 

 whirlwinds in thofe torrid regions. As the defcrip- 

 tion of thefe pillars is in fome degree blended with 

 that of the fimoom, I fhall extract the whole pafiage. 

 In relating the particulars of his journey acrofs a 

 certain part of the dcferts of Africa, Mr. Bruce ob- 

 ferves, c We were here at once furprifed and terri- 

 fied by a fight furely one of t the moft magnificent in 

 the world. In that vaft expanfe of defert, from weft 

 and to the north weft of us, we faw a number of pro- 

 digious pillars of fand at different diftances, at times 

 moving with great celerity, and at others (talking ori 

 with a majeftic flownefs j at intervals we thought they 

 were coming in a very few minutes to overwhelm us ; 

 and fmall quantities of fand did actually more than 

 once reach us. Again they would retreat fo as to be 

 almoft out of. fight, their tops reaching to the very 

 clouds. There the tops often feparated from the' 

 bodies j and thefe, once disjoined, difperfed in the air, 

 and did not appear more. Sometimes they were 

 broken near the middle, as if (truck with a large can- 



* " So where our wide Numidian waftes extend, 

 Sudden th' impetuous hurricanes defcend, 

 Wheel through the air, in circling eddies play, 

 Tear up the fands, and {Veep whole plains away , 

 Th'. affrighted traveller, with wild furprife, 

 Sees the dry defert all around him rife, 

 And, fmother'd in the dufty 'whirlwind, dies." 



Addifon's Cato. 

 H h 2 non 



