16 



to be noted. The dry bulb on the bridge frequently stood at 38° 

 F., while the ship was cruising in the cold current near the Tail. 



Four hundred and thirty-six reports of ice were received and twelve 

 vessels were sent special ice information on request. There were, as 

 usual, a number of reports of drifting buoys and spars. The isotherms 

 on the fifth cruise chart are based on 150 observations of the patrol 

 supplemented by just over 1,000 values sent in by 163 different co- 

 operating vessels. 



THE SIXTH CRUISE, " MODOC," JUNE 18 JULY 2 



At daylight on June 19 the Modoc started searching toward the 

 southeast for a berg reported the day before from 42° 10' N., 48° 12' 

 W., but this berg could not be found although search was continued 

 throughout the 20th for it. 



The 21st, 22d, and 23d were spent searching northwestward to and 

 past 43° 00' N., 52° 00' W. Excellent and at times phenomenal visi- 

 bility prevailed. On the 23d the Modoc sighted 18 bergs to the south- 

 west, west, and northwest of the Tail. When cooperating vessels re- 

 ported six additional bergs south of the forty-third parallel on the 

 23d and 24th it was felt that every berg comprising the southern, 

 western, and eastern limits of the ice at the time was located and 

 known, for reporting vessels and the Modoc had thoroughly covered 

 the entire critical area. 



On the 24th courses were run to the southeast for a berg reported 

 in 42° 00' N., 50° 00' W. A small berg 18 miles to the northeast of 

 this position was sighted, but no large berg could be found. During 

 the night the Modoc experienced a 2-knot current setting eastward in 

 the warm water. The rapid and varying currents so frequently found 

 along the junction of the Gulf Stream and the Labrador Current 

 probably account for much of the difficulty experienced in trying to 

 find bergs in the southeastern sector, even when the searches are 

 based upon ice reports less than 24 hours old. 



The 25th and 26th were devoted to searching in the southeast 

 branch of the cold stream for the southeastern limits of the ice. No 

 bergs were sighted. Due to fog patches that at times interfered with 

 visibility, the search plans had to be frequently altered and occasion- 

 ally the patrol had to drift until conditions improved. As the 27th 

 was foggy a large part of the day, little could be done other than to 

 retain position against the strong current setting eastward along the 

 temperature wall. Few ice reports were received on the 26th and 

 27th on account of the fog. The 28th commenced foggy, but north- 

 west breezes cleared the weather over the cool water before noon, 

 permitting a large area along the forty-second parallel between the 

 forty-eighth and fiftieth meridians to be covered before dark. Again 

 no bergs were found. 



