over a period of 5 hours, the general direction of set being a little 

 north of east. Figure 18, also illustrates this point. In the upper 

 waters, however, the general direction of set was to the northwest and 

 west as shown in figures 9, 11, 13, 15, 19, and 20. In Figure 22, a 

 contrast of current direction is shown at depths of 30 and 400 meters. 

 Exceptions to the general rule of currents setting to the west and north- 

 west in the upper levels occurred on 14 June 1960 (Fig. 13) and at the 

 last two stations measured on 28 and 30 December 1960 (Figs. 24 and 25). 



The currents observed at the icehole appeared to be tidal in 

 origin or were at least influenced by the tide. This is shown in Fig- 

 ures 12, 16, 18, 19, and 24. Drift ranged from 0.01 knot to 1.83 

 knots. The maximum drift was observed at 400 meters depth on 28 De- 

 cember 1960. A drift of 1.50 knots also was noted at the same depth 

 on 17 December 196 0. The average of all measurements of drift taken 

 was 0.30 knot. The set of the maximum current drift observed on 28 

 December was 88° and that of the 17 December reading was 66°. A 

 pressure type tide gauge was in operation at Scott Base on Pram Point, 

 about 2 miles to the north of the icehole, during part of the time of 

 observation. Tidal states, furnished through the cooperation of the 

 New Zealand scientists working at Scott Base, are noted on some of the 

 figures. 



It had been expected that a portion of the strong current which sets 

 westerly along the Ross shelf ice edge turned under the ice at Cape 

 Crozier (at the extreme eastern end of Ross Island) and flowed south 

 of the island and out into McMurdo Sound. An attempt to measure 

 currents at the shelf ice edge near Cape Crozier with an icebreaker as 

 a platform, had to be abandoned when a reconnaissance flight showed the 

 shelf ice to be much too high for mooring. Located some 10 miles to 

 the south of the icehole station are White and Black islands, and 

 Minna Bluff. These form a southern boundary to the water area, and it 

 is the opinion of the present authors that the current observed at the 

 icehole is part of a large eddy which is a continuation of the Hut 

 Point current. In the outer portions of McMurdo Sound, the current 

 comes around Cape Byrd from the east, sets south along the western 

 shores of Ross Island and then the greater portion cuts across the 

 sound to the opposite shore and flows north along the Victoria Land 

 Coast. There is very little current in evidence in the central por- 

 tion of McMurdo Sound south of Cape Royds, but, along the shore at Hut 

 Point and at Cape Armitage a strong current flows amounting to as much 

 as 3 or 4 knots. This has been known since Scott's time to reverse its 

 direction of flow with the tide. Apparently this current continues 

 south and flows around and back out into the Sound again. On the other 

 hand there may be some water, especially at greater depths, which 

 flows toward the east, and this may go out from under the edge of the 

 shelf ice near Cape Crozier. This question can be decided only when 

 it is possible to measure the direction of flow of currents at Cape 

 Crozier. 



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