56 NATURAL HISTORY. 



ger. A petrifying lake in Iceland, is also mentioned, 

 and the lake Neagh in Ireland, 1ms also the same pro- 

 perty of apparently turning wood, &c. into stone ; 

 but these petrifications are no other than incrustations 

 like those made by the water of Arcueil. 



CHAP. III. 



OF TIDES, OF WINDS, ' REGULAR AND IRREGULAR 



MONSOONS HURRICANES WHIRLWINDS 



WATER-SPOUTS. 



W ATER, like every other fluid, remains smooth 

 and tranquil, unless put in motion by some foreign 

 cause. All the waters of the ocean are collected in 

 the lowest places upon the surface of the earth ; and 

 hence the motion of the sea must proceed from exter- 

 nal causes. The chief motion is that of the tides, 

 which rise and fall alternately, and which produce a 

 perpetual motion from east to west. These two mo- 

 tions have an unvariable relation to the motions of 

 the moon. During the full and new moons, this mo- 

 tion from east to west is most observable, as well as 

 that of the tides, which ebb and flow upon most coasts, 

 every 6^ hours. It is always high tide when the moon 

 arrives at the meridian ; and it is always low tide 

 when the moon is at the greatest distance from it. 

 The motion from east to west is perpetual ; because 

 when the tide rises, it pushes an immense body of wa- 

 ter from east to west, and the ebbing seems only to 

 be occasioned by the smaller quantity of water which 

 is then impelled westward. 



