aged 15 miles per clay rroiii tlit' lOtli to l;Uh and 35 miles per day 

 Irom the 13th to 16th. During these same periods the outer edge of 

 the pack in which the bergs were drifting advanced at 35 miles and 

 20 miles per day respectively. Part of this apparent difference in 

 drift rate of bergs and pack arises from the wasting of the pack 

 ice, which is especially rapid at its outer border. The wake of 

 open water frequently observed in the lee of a berg in an ice field 

 is evidence, however, of the actual difference in drift rate. At 

 times, these clear wakes may extend from the berg for a distance 

 of several times the width of the berg. When scouting from a 

 plane the contrast of the dark water of the wakes against the white 

 ice field is an excellent aid in spotting bergs. The movement of 

 bergs owing to their great draught is predominantly determined 

 by the subsurface currents, but that of the field ice by surface 

 currents and winds. On a very windy day small wakes may 

 often be seen behind the growlers and heavier cakes of pack ice. 



Icebergs were little menace to navigation during most of March 

 as they were well inside the pack limits. It was not until the 22d 

 that bergs were observed clear of the pack near its southeastern 

 extremity at that time in the vicinity of 46°23' N., 46°50' W. After 

 the 22d such bergs as were released probably scattered rapidly to 

 the south, although the ones sighted were near the pack limits. 

 By 5 April bergs were strung out as far as 43°26' N., 48° 18' W., 

 approximately 190 miles from the position of the tip of the pack on 

 22 March, but others easily may have been scattered farther. 



In April the forming of new ice in the Newfoundland area no 

 longer was a factor, any extending of the ice limits stemming from 

 a southerly drift of heavier ice. The maximum limit of sea ice 

 shown on the monthly chart corresponds roughly to the limits at 

 which relatively heavy ice was seen at one time or another. The 

 greatest drift of this ice to the south occurred during the first 

 few days in April. On 5 April (see figure 19) heavy ice was ob- 

 served at a position of 44°17' N., 48°25' W., but south of 45^10' N., 

 the remnants of what had probably been a compact tongue on the 

 2d was broken into scattered patches. A few vessels encountered 

 the tongue on the first and second and detoured to the south although 

 one was fortunate to find a break. The ice was compact and heavy 

 and except at the occasional breaks navigable only by strongly ice- 

 reinforced ships. After 5 April the pack receded rapidly with none 

 sighted south of 45°40' N., 48° 15' W., on the 9th. Patches but no 

 extensive areas of compact ice remained south of the 48th parallel 

 on the 22d. Along the inshore branch of the Labrador Current 

 patches of quite heavy pack were sighted south past St. John's from 

 time to time threatening but not blocking the port. For the area 

 south of the 50th parallel the maximum limit of sea ice shown on 



51 



