SCIENTIFIC RESULTS 159 



(lie forty-fourth and forty-fifth parallels. The current surveys of 

 1!)2G and 1927 (see Smith 1927 and 1927b) proved such is the case 

 wiien the cold current is weak or the warm alinormally voluminous. 

 In some years this phenomenon is more j^ronounced than in others, 

 hut whenever well developed it definitely blocks the path of the 

 l)('r<rs from reachin<^ the Tail of the bank, and deflects them out 

 southward and to the eastAvard. An excellent illustration of this 

 is to be seen in the charts for 1920. (Smith 1927b, pp. 86 and 90, 

 and fi<>: 99, p. 155 of this paper.) For several years past this inshore 

 development of the Gulf Stream on the east side of the bank in June 

 and July, insuring safety to the steamship tracks, has been thou»>ht 

 to warrant the discontinuance of the ice patrol for the year. 



{e) The chan«:e in alternation in direction of flow between the 

 warm and cold Avater masses takes place about 25 miles shoreward 

 fi<mi the "cold AvalP' or temperature wall. (See fig. 122, p. 204.) 

 It is for this reason that icebergs are seldom sighted offshore of the 

 cold-water area south of Newfoundland and that they often drift 

 along parallel to the Gulf Stream, though lying many miles within 

 tlie offshore boundary of the cold, mixed waters. 



Icebergs around NcAvfoundland have been trailed by the ice pati'ol 

 as they drifted many hundreds of miles in the current ; in fact the 

 compilation of individual berg drifts in the area south of the Tail 

 of the Grand Bank constitute the most positive evidence to refute 

 the old belief that the Labrador current floAved southAvard along the 

 Tnited States coast. (See figs. 102 and 107.) The first attempts to 

 folloAv the movements of an iceberg near the Grand Bank Avere by 

 dohnston (1913, p. 23) Avhen the /Seneca kept in touch Avith tAVo bergs 

 for over a period of live Aveeks. finding that they drifted in a large 

 cyclonic vortex off the east side of the Grand Bank. The next in- 

 stance was in 1915 Avhen a berg Avas foUoAved for 17 days Avhile it 

 (hifted 195 miles in a Avide semicircle south of the Tail, first to the 

 AvestAvard at the rate of 12 miles per day and then eastAvard in the 

 ( iulf stream at 24 miles per day. In 1921 on the ice patrol Ave began a 

 l)olicy of tracking the bergs Avhenever possible, and the composite map 

 of drifts (fig. 102 ) so compiled has noAv become very instructive. Some 

 of these folloAv: A])ril 11 to May 12, 1921, a large berg drifted from 

 the northeastern edge of the Grand Bank to a point 90 miles south- 

 soutliAvest of the Tail at an average rate of 15 miles per day; thence 

 it Avas carried eastAvard on the Gulf Stream for 10 days at the rate 

 of 28 miles per day. March 19 to April 15, 1922, a berg drifted Avest- 

 ward past the Tail of the Grand Bank, then south and east, a total 

 distance of 315 miles at an average velocity of 12 miles per day. 

 May 2 to 20 three bergs set southAvestAvard past the Tail of the Grand 

 Haiik in a large anticlockAvise eddy at the speed of 10 miles per day 

 and a total distance of 175 miles. March 16 to April 11, 1924, a 

 I .'erg on the northeastern part of tlie Grand Bank drifted south into 

 tiie Gulf Stream a total distance of 450 miles. The rate of drift Avas 

 sloAV to the forty-third parallel, but south of the Grand Bank it 

 increased to 24 miles per day. May 19 to June 30, 1925, a berg Avas 

 folloAved over a distance of 492 miles as it drifted from the forty- 

 fifth parallel southAvard along the east side of the bank to the Tail 

 and thence southAvesterly until turned easterly by the Gulf Stream. 

 May 2() to June 2, 1928. a berg Avas traced 265 miles in a semicircular 



