6 



crossed the principal westbound "B" tracks, one southeast and twO' 

 east of the Tail. 



After May 24 no bergs were sighted or reported, except north of 

 the Grand Banks and along the Newfoundland coast in the vicinity 

 of Cape Race and St. John's. Throughout the season, the usual 

 extension of cold water to the westward around the Tail of the Banks 

 was largely absent. 



During the 1930 patrol season 67 oceanographic stations were 

 occupied for the purpose of continuing the annual study of currents 

 and subsurface oceanographic conditions. Salinities of all water 

 samples taken at the stations Avere obtained by the electrical con- 

 ductivity method before the discontinuance of patrol, and the sta- 

 tions were at once dynamically calculated in accordance with formulas 

 in Coast Guard Bulletin No. 14. 



The other main features of the scientific program consisted in tak- 

 ing soundings with the fathometer and in constructing numerous 

 isotherm charts. During the season cooperating vessels sent in by 

 radio 6,097 water temperature reports. These values, combined with 

 those taken from the logs of the patrol ships themselves, permitted 

 the construction of weekly isotherm charts. In addition the usual 

 isotherm chart was made for each 15-day patrol cruise. Such sur- 

 face temperature charts are of great importance to the patrol, consti- 

 tuting the best aids that the patrol at present possesses for predicting 

 the movements of the ice, or for determining its probable distribution 

 at any time. 



Radio communications were more voluminous in 1930 than in any 

 other year except 1929, which had a longer and a very much heavier 

 ice season. As in previous years, the most gratifying cooperation by 

 radio was had from ship and shore stations. 



During the 1930 patrol season there were no disasters near the 

 Grand Banks due to collision of ships with ice. A year of safety 

 should not blind the eyes of the shipping world to the slight but real 

 danger of such collision. During times of bad visibility, shipmasters 

 should exercise due care. They should remember that the patrol 

 vessels often experience dense fog for several days at a time. When 

 this occurs their store of up-to-date ice information is at best very 

 meager. Even under the best weather conditions the patrol vessel 

 can broadcast the position of only such ice as has been sighted or 

 reported. There always exists the possibility of unreported ice. 

 During darkness and bad visibility great caution should always be 

 used while running through areas where either past records or present 

 conditions indicate that ice is liable to be found. 



