DERELICTS AND ICEBERGS 51 



much further away from aloft than from the 

 decks, in a dense fog the man on decL can 

 often sight a berg farther away than the look- 

 out can, owing to the fact that the water 

 lapping about the base of the berg is more 

 readily distinguished than thq ice itself. 

 Moreover, on large ships, the lookout is fre- 

 quently so far above the water that he may 

 have an unobstructed view of the horizon even 

 though a good-sized mass of ice may be within 

 the distance of a mile, and hence at night he 

 may fail to see it at all, whereas if he was 

 lower down, the ice would loom above the 

 edge of the horizon. So too in using search- 

 lights the lookout is often hindered instead 

 of helped, for if he stands behind or beneath 

 the beam of light he can see nothing. If, how- 

 ever, he stands fifteen feet away on either 

 side he can see readily and he can distinguish 

 bergs even when he stands a hundred feet or 

 more back of the light. 



Besides seeing bergs mariners are often 

 warned of their proximity by other means. 

 Among these are sound, for a large berg will 

 frequently give ofif an echo which may be 



