58" 



5r 56° 55° 54" 53° 52° 51" 50° 49° 48° 47° 46° 45" 44° 



54° 53° 52° 51° 50° 49° 48° 



Figure 13.— Surface Isotherms for the period 15-31 March 1958. 



515507 O-60 (Face p. 14) No. 3 



