298 THE ATMOSPHERE AND METEOEOLOGY. 



should not be able to 'understand how in the very centre of the 

 hurricane the effects produced by the wind differ in so remarkable a 

 manner in a space of small extent. Thus, according to Reid, it has 

 often been ascertained that during the cyclones of Mauritius lofty 

 houses half in ruins already, were not even shaken by the storm, 

 while solid buildings beside them were completely overthrown and 

 destroyed.* 



Isolated whirlwinds are sometimes propagated with a rapidity as 

 great as that of the hurricanes, and may cause similar disasters. The 

 whirlwind which passed over Malaunay and Monville on the 19th of 

 August, 1845, was not more than 33 to 44 yards wide in certain places, 

 and in its greatest breadth it hardly attained the third of a mile ; 

 notwithstanding which it committed the most terrible ravages, and 

 the inhabitants of that part of Normandy long preserved the fearful 

 memory of it. About one o'clock in the afternoon, after an oppress- 

 ive day, during which the barometric column had suddenly fallen from 



299 to 27'8 inches, some sailors saw the whirlwind forming over 

 the Seine at the foot of the high cliffs of Canteleu. Like an inverted 

 pyramid, blackish at the base and red at the summit, the whirlwind 

 swept tlie waters with its point and then rushed into the valley of 

 Marorame. It did not advance in a straight line, nor by elongated 

 curves, but by abrupt deviations to right and left, like the zigzag of 

 lightning. Through the woods which were on its path, it traced 

 wide roads over trees overthrown, shattered, and reduced to ruin ; 

 then approaching successively three great silk manufactories of 

 Monville, it twisted them in its spirals, and struck and destroyed 

 them. After having heaped up all these ruins, under which perished 

 hundreds of workmen, the whirlwind opened an avenue in the ruins 

 on the plateau of Cleres, then divided into two branches and ascended 

 into space, carrying with it all kinds of objects, planks, slates, and 

 papers, which fell down again near Dieppe at distances varying from 

 15 to 24 miles from the place of the catastrophe, f It is evident, 

 according to all accounts, that electricity pla3"ed a very great part in 

 the whirlwind of Monville. 



These phenomena, as we can understand, produce different effects 

 according to the region that they traverse. Those which pass over 

 Ibrests break the trees or even twist them in various directions. Others 

 which traverse large prairies_, such as the pampas of Buenos- A yres, the 

 steppes of Turkestan, and the grassy countries of Central Africa, raise 



* Lartigue, Essai sur Us Ouragans et les Tempetes, p. 89. 

 t Eugene Noel, Bocumsnts Iiiedits ; Dagnin, Traite de Physique. 



