20 



The 16th was spent watching the same two bergs as they continued 

 to move northeastward away from the tracks. By the morning of 

 the 17th they were drifting a little south of east, however, being, 

 at 6.30 a. m."^near 41° 45' N., 48° 35' W. The smaller of the two, 

 marked by a layer of dirty black ice, was by this time much reduced 

 in size and so much cut up by wave action as to be ready to break 

 up into three pieces at any time. At 7.40 a. m. course was set for a 

 large berg with growlers reported from 42° 07' N., 50° 11' W. Visi- 

 bility was excellent, but no unreported ice was sighted on the way. 

 The berg proved to be a very large, solid one over 125 feet high, 

 floating in 58° surface water. From this berg westerly courses 

 were steered to a rendezvous with the Modoc in 42° 00' N., 52° 00' 

 W., near which position relief of patrol was effected at 1 a. m. on 

 July 18, 1929. 



Bergs did not curve around the Tail to the westward during the 

 seventh cruise as they did during earlier ones. The ice, blocked 

 from the southwest sector by a warm tongue, was carried by a push 

 of cold water between the forty-eighth and fiftieth meridians farther 

 south than at any other time during the year. Two or three different 

 bergs were reported as south of 41° 30' N. and six or eight different 

 bergs drifted below the forty-second parallel. Throughout most of 

 the seventh cruise the Tampa guarded these southeastern bergs and 

 watched their disintegration. 



There were about 20 bergs reported from along the eastern edge of 

 the Banks and 60 from along the "F" tracks north of the Banks 

 between 47° west and Cape Race. This was an unseasonably large 

 number, but nevertheless it marked a considerable falling off as com- 

 pared with the sixth cruise. The number of different bergs south of 

 the forty-eighth parallel during the seventh cruise was only about half 

 that during the sixth cruise, while the sixth cruise recorded about 

 half as many as the fifth. It was evident that the ice was melting 

 at higher and higher latitudes and that the arrival of the date when 

 bergs would no longer be a menace to the "B" tracks would only be 

 a matter of a short time. 



The salinities of water samples from the seven stations taken on 

 the Modoc were determined in the salinometer on the first two days 

 of the Tampans cruise. Nine oceanographic stations were taken on 

 the seventh cruise, usually near bergs after the vessel was through 

 cruising for the day. These salinities were determined also and all 

 the stations were worked out before the Alodoc was met on July 18. 

 The oceanographic apparatus worked well. It was found that the 

 warmth in the Labrador Current was confined to the surface layers. 

 Even south of the forty-second parallel where the water was 56° to 

 64° F. at the surface, 37° and 38° water at the 125-meter level was 

 found at all stations. Farther north the cold water was encountered 



