344 THE OCEAN. 



canvas can be secured, the gale is howling shrilly 

 through the spars and rigging, and the crests of 

 the waves are torn off, and driven in sheets of spray 

 across the decks. The lightning is terrible : at very 

 short intervals the whole space between heaven and 

 earth is filled with vivid flame, showing every rope 

 and spar in the darkest night as distinctly as in the 

 broadest sunshine, and then leaving the sight ob- 

 scured in pitchy darkness for several seconds after 

 each flash; darkness the most intense and absolute; 

 not that of the night, but the effect of the blinding 

 glare upon the eye. The thunder, too, peals now 

 in loud, sharp, startling explosions, now in long mut- 

 tered growls all around the horizon. In the height 

 of the gale, curious electrical lights, called St. Ulmo's 

 fires, are seen on the projecting points of the masts 

 and upper spars, appearing from the deck like dim 

 stars. Soon after their appearance the gale abates, 

 and presently clears away with a rapidity equal to 

 that which marked its approach. 



The storms are found, by carefully comparing 

 the directions of the wind at the same time in dif- 

 ferent places, or successively at the same place, to 

 blow in a vast circle around a centre : a fact of the 

 utmost importance, as an acquaintance with this 

 law will frequently enable the mariner so to deter- 

 mine the course of his ship, as to steer out of the 

 circle, and consequently out of the danger; when, 

 in ignorance, he might have sustained the whole 

 fury of the tempest. The course of the circle is the 

 opposite of that taken by the hands of a watch, and 

 is the same with that of the still more striking phe- 



