30 



Figure 17.— Weather diagram, fourth cruise 

 MAY 23 TO JUNE 12, 1931 



Maximum air temperature, 53° F. 

 Mininum air temperature, 35° F. 

 Mean air temperature, 42.7° F. 



Visibility was less than 4 miles, 44.9 per cent of the time. 

 Visibility was less than 2 miles, 37.1 per cent of the time. 

 Figure 17 shows the meteorological graph. 

 Figure 25 shows the track of the vessel. 



In Figure 25 there are no meteorological observations plotted for 

 the days 6th, 7th, and 8th of June, due to our staying in port. 



