18 



to the Tail, a very favorable condition for preventing any more bergs 

 from curving around it and drifting to the west. 



Seven oceanographic stations were taken. Accidental breaking of 

 a glass carboy containing all the silver nitrate solution of the patrol 

 prevented the immediate determination of the salinities of the water 

 obtained, so the cases of water samples were taken to the Tampa 

 for analysis in the electric salinometer on board that vessel. 



Weather was again extremely moderate and seas were generally 

 smooth. There were only four hours of winds of gale force and 

 seven hours of strong breezes. Fog was recorded 23 per cent of the 

 time, and visibility of less than 4 miles 39 per cent of the time. 



Three hundred and seventy-two ice reports were received from 

 ship and shore stations. Special ice information was sent on request 

 to 10 vessels. The cruise isotherm chart is based on the observa- 

 tions of the Modoc, as supplemented by 829 temperature reports 

 received by radio from 151 cooperating vessels. 



THE SEVENTH CRUISE, " TAMPA," JULY 3-18 



The region southwest of the Tail having just been well searched 

 by the Modoc, the Tamjm on taking up the ice-patrol duty on July 

 3 steamed eastward slowly through dense fog to a position from 

 which to search south and east of the Tail as soon as visibility 

 permitted. 



The opportunity came the next morning and advantage was taken 

 of the good weather by running under forced draft during all day- 

 light hours on the 4th and 5th. The southeastern limits of water 

 less than 50° F. at the surface were accurately determined, and the 

 southeast sector was carefully searched for ice. Two small bergs 

 and one large one were all that could be found south of the forty- 

 third parallel and east of the fiftieth meridian. The warm water 

 seemed to be crowding north rapidly, and very little water cooler 

 than 60° F. at the surface was left south of the forty-second parallel. 



Visibility being good at times on the 6th, the patrol was enabled 

 to search north to the Tail and thence east along the forty-third 

 parallel to the forty-ninth meridian. One berg in 55° water at 42° 

 24' N., 49° 51' W., was the only ice sighted. In view of steadily 

 improving conditions existing in all parts of the patrol area, word 

 was sent the Coast Guard headquarters that the steamship tracks 

 could be safely shifted north from "A" to "B" lanes. The latter 

 tracks began to be used on July 13. This recommendation, as will 

 be seen later, proved premature, but at the time made it seemed 

 thoroughly sound. 



The 7th and 8th were days of very extensive dense fog, and the 

 Tampa was forced to drift, waiting for good visibility before resum- 

 ing the search for the southern limits of ice and cold water. No 

 ice was either sighted or reported on the 7th. A few reports cama 



