Chap, ii.] Hurricanes. 4 59 



long arcades opening at one end, the wind blows with 

 great force along them. From this increafed dehfity 

 it is, that we meet with fdch cold blafts at the corners 

 of frreets. In fhcrt, whatever diminimes its bulk, 

 without taking entirely away from its motion, increafes 

 the vehemence of the wind. This alfo is the reafon 

 why the air reflected back from the fide of a mountain 

 is often more violent than the air which firft ftruck its 

 fide i for it is by this means condenfed, and its force 

 augmented. The countrymen and farmers have a 

 diftinftion which is not without its foundation ; for 

 they make a difference between a fwift and an heavy 

 florin : the fwift ftorm is loud, boifterous, and inoffen- 

 five; the heavy ftorm more bpiftercus and alfo more 

 dangerous. This fhewr- the infurEciency of thofe in- 

 ftrnments made for meafuring winds, by meafuring the 

 rapidity only with which they move*.' 



It would be happy indeed for fcience and for man- 

 kind if thefe refearches could have been carried further. 

 To predict an eclipfe, fays a late writer, is an object 

 merely of curiofity ; to predict an approaching ftorm 

 would be of inconceivable benefit. What is (till un- 

 accomplimed with refpect to our own climate, has how- 

 ever been attempted with refpecl to thofe alarming 

 itorms which happen in the Weil-Indies, and which 

 are commonly denominated hurricanes. 



Thefe dreadful convulfions of nature, Dr. Perkins^ 

 of Bofton, in America, fuppofes to be caufed by fome 

 occasional obftruftion in the uiual and natural progrefs 

 of the equatorial trade winds. The reafon he aiTigns 

 for this conjecture is, the more than ufual calm which 

 commonly precedes them. Iti the natural courfe of 

 the trade winds, the air rifes up in the line, and pafles 



*Goldfmith's Plxilofophy, vol. ii. p. 143. 



off 



