149 



contour of ihe eastern edge of the Bank. It seems probable that this 

 is the diurnal tidal wave (which extends to the bottom) meeting the 

 obstacle of the Bank: the former is accelerated so much that it 

 becomes visible in the form of rips on the surface. 



Third: Three observations at four-hour intervals in lat. 43%"05', 

 long. 50° 03', near the Tail of the Bank, in 75 meters (41 fathoms) of 

 water, gave the following data: 



A comparison of the temperatures in the above table indicates a 

 rapid change of measurable magnitude, all of which is further evidence 

 that an active mixing occurs in the water on the Grand Bank. 



Fourth: A comparison of profiles No. 9 and No. 14, the vertical 

 sections which run from the Tail to Cape Race, shows that a great 

 change in temperature and salinity occurred May 9 to June 23 in the 

 water lying over the Bank. Attention is called to the effects of 

 changes in barometric pressure, and wind friction of the surf ace layers, 

 both of which undoubtedly play a very important role in the move- 

 ments of this very interesting body of water. All this accumulation 

 of evidence justifies the statement that the water over the Grand 

 Bank is in a continuous lively state of circulation. 



More Ai'ctic water was transported around the Tail and to the 

 northwestward along the southwest slope of the Bank in 1923 than in 

 any previous year since the inauguration of the patrol, a statement 

 substantiated by the record of bergs, more being set in on the south- 

 west slope and to the northwestward, under the control of this circu- 

 lation, than in any previous year. In all cases during 1923 the cold 

 water distribution and the berg distribution corresponded closely. 



Summary of the features of 1 923 . — (1) Invasive shoulder of Gulf 

 Stream east of Bank. 



(2) Offshore movement to south-flowing waters on east side of Bank. 



(3) Variations in the size and velocity of the Labrador Current. 



(4) Movement of Arctic water westward along southwest slope. 



(5) Tendency of Labrador Current to spread in on bottom of Bank. 



(6) Progressive freshening and warming over central part of Bank, 

 especially well marked in the surface layers, with the advance of the 

 season. 



