86 



the Grand Bank. Attention is drawn to the fact that in all three of 

 those drifts the movement of the bergs was counter-clockwise. Con- 

 clusions based upon the distribution of the surface water, as regards 

 temperature, caused this statement last year:^ 'It would seem fair 

 to assume that a great eddy exists on the west side of the Tail of the 

 Grand Bank at this season." The circulation in this area probably 

 is not restricted to one eddy only, but the tendency for eddies to form 

 to the westward and northwestward, off the southwest slope of the 

 Grand J5ank, is a well established fact. 



Very little has been written regarding the effect of wind upon the 

 drift of icebergs. It is intended to present several cases of bergs 

 the drifts of which, with the prevailing direction and force of wind, 

 are known. The wind action is of two kinds — (a) the direct force of 

 the wind as applied to the exposed surface of the berg and (b) the 

 indirect effect of the wind as applied through its frictional action in 

 setting up a current in the water mass in which the berg floats. The 

 effect of (a) under this classification is greatest on the "sailer" berg, 

 which, by virtue of its lofty sides and shallow draft, is popularl}" 

 supposed to spread its wings and schoon off before the gale. 



With regard to the action of the wind upon the berg, attention is 

 called to the close similarity between the drift of the berg west of 

 the Grand Bank, as shown on chart "H," 1921,^ and the drifts of 

 bergs 11 and lla on charts "B" and "C." During the period May 

 24 to June 4, 1921,^ which covers the drift of the berg on chart "H," 

 the winds were south-southeasterly and southwesterly, force 4 to 5. 

 April 8 to May 15, 1923, the winds were divided between the south- 

 east and northwest quadrants, force 3^- This covered the period of 

 berg 11. May 3 to June 18, 1923, the winds were easterly and 

 southerly, force 3, and this covers the period of berg lla. Con- 

 sideration of the great similarity of the tliree di'ifts and the dissimi- 

 larity of the winds forbids any relationship between the wind and the 

 drifts in the above cases. 



Similarly, several bergs in the eastern theater during the early 

 part of the season of 1923 (see chart "G") drifted in a northeasterly 

 direction for several days, while the wind blew from the northwest 

 quadrant with a force of 6, part of the time with a force of 8 and 10. 

 In spite of this gale the bergs drifted at right angles to the wind at 

 the rate of 0.6 knot per hour, following the flow of the Gulf Stream. 



The drifts assumed by 9 bergs from May 2 to July 14, 1922,® afford 

 another excellent opportunity to observe the effect of wind upon ice- 



« 1V22. Smith. Edward H.: International Ice Observation and Ice Patrol Service, V. S. Coast Guard 

 Bulletin No. iO, p. .V,. 



»1921. Smith, Kdward H.: Ice Observ.. etc., Bull. No. 9, chart "11." 



• 1822. .'^mlth. Edwiinl H.: Ice Observ. and Ice Patrol Serv.,- U. S. C. Q. Bull. No. 10. charts "V 

 and "O" fnrinR p. 98 and pp. Bl and M. 



