ICEBERG6 IN NAVIGATION BARNES. 



727 



In the lower part of the diagram a map is shown giving the edge 

 of the ice, the ship's course, and the direction of the current. It 

 will be seen that the temperature is everywhere a measure of the 



hnes. 



ship's distance from tJic ice slicet taken ak)ng tlic current 

 Thus the temperature curve gives us the contour of the ice. 



Having so determined the presence of the ice sheet, even in water 

 less than one-tenth of a degree above the freezing point, I determined 



