8 



ciding what course of action to follow appears to be a function of 

 the time of year. The field ice in the early spring will be of greater 

 extent and more compact character than that met with later in the 

 season. The Ice Patrol records show that this year, and therefore 

 in any similar years, the shipmaster should consider it unwise to 

 try to run througii the ice before the middle of April when north of 

 latitude 45°30' N. After skirting the ice to this latitude he should 

 pass through, by using due caution, without damage. About April 

 15 he should find the field ice more open and covering less area, and 

 track E should be passable. In the light of this season's records 

 track F should be considered distinctly unsafe before May 1. 

 It must be remembered in these matters, that the statistics of one 

 particular season are iiardly applicable to every season. An average 

 of conditions over many years, however, shows the above observations 

 to hold true. It is interesting to note, in this particular, that accord- 

 ing to the North Atlantic Track Agreement, as revised March 1931, 

 track E oiRcially opens April 11, and track F not until May 16. The 

 shipmaster has learned to combat the iceberg menace by using ex- 

 treme caution Avhile unavoidably passing through areas known to 

 contain bergs. He nmst learn to combat the field ice menace by 

 staying out of it. 



The scientific program this year, as in the last 5 years, was 

 j-estricted to periodic dynamic surveys of the principle region of 

 activity. The oceanographic program is seldom commenced before 

 the 1st of April. The extreme storminess of the Grand Banks 

 region in the early months of spring make such operations nearly 

 impossible. Three such maps were completed and delivered to the 

 Patrol vessel, one in April, one in May, and one in June. (See figs. 

 19, 20, and 21.) These maps are used by the Patrol vessel in estimat- 

 ing the velocity and direction of drift of the bergs. Tw^o striking 

 examples of the value of these" maps are provided by the long drifts 

 of tAvo bergs this season (fig. 2). Many other examples of the corre- 

 spondence between the current maps and the actual drift of bergs 

 were noted throughout the season, but these two stand out because of 

 their length and the continuity of observation by the Patrol vessel. 

 The maps are also used in planning the areas to be searched after 

 days of fog or gales when the ice conditions are largely unknown. 

 It can be seen by an inspection of the current maps (figs. 19, 20, and 

 21) that bergs in certain areas are definitely dangerous Avhile in other 

 areas they would surely drift directly aw^ay from the steamer tracks 

 and to the northeastward out of the sphere of the Patrol. A proper 

 interpretation of a current map will show, then, those areas which 

 are likely to contain ice; those which surely would not contain ice; 

 and what ice, if found, would prove dangerous. The portion of the 



