SCIENTIFIC RESULTS 133 



the ocean current and its replacement by the Avinds."^ As a berg 

 melts, the increasing irregularities of its contours give the wind a 

 greater and greater hold. 



The effect of the wind on icebergs is of two kinds, (a) the direct 

 force of the Avind as applied to the exposed surface of the berg itself 

 and (b) the indirect effect of the wind as it tends to set up a fric- 

 tional current in the surface layers of the sea. 



(«i) Few data, if any, are available regarding the force exerted 

 by a Avind on the sides of an iceberg. The pure wdnd effect on the 

 patrol ship in the ice regions, exclusive of frictional wind current 

 generated, is therefore employed as a guide. This is estimated to 

 amount to 17 miles per day, with a Avind force of G to 7 on the Beau- 

 fort scale and 11 miles per day Avith a Avind force of 4 to 5. The ratio 

 of exposed portion of the ship to submerged is about 2 : 3, Avhile in 

 the case of icebergs Ave have shoAvn on page 112 this varies from 

 1:5 to 1:1, largely depending upon the form and state of disin- 

 tegration. The folloAving table giA'es the wind movement for the 

 various type of bergs, based on that of the ship, assuming that the 

 direction of its drift is the same as that of the wind and disregarding 

 the coefficient of surface friction : 



Class of iceberg 



Drift of Ice ' 



Wind Beau- 

 fort 4-5 



Blocky 



Rounded and domed 



P icturesque Greenland 



Pinnacled and ridged 



Last stages, winged and horned . 



1.5 

 1.8 

 2.2 

 3.7 

 7.3 



AAlnd Beau- 

 fort 6-7 



2.3 

 2.8 

 3.7 

 5.7 

 11.3 



^ Miles per day. 



(6) Since Ekman (1905) has published his epoch-making theory of 

 Avind currents in the sea as deflected by earth rotation, much attention 

 has been paid to the subject by dynamic oceanographers.*'^ Admit- 

 ting that the stratification of the water column and also several 

 other conditions greatly modify the ideal theoretical development of 

 a wind current, it may be estimated that a moderate to fresh Avind 

 blowing for a day or tAvo in the ice regions Avill establish a movement 

 of the Avater layers to a depth of 200 feet, and a strong breeze to 

 moderate gale in the same interval to a frictional depth of 300 feet. 

 The mean velocity of movement, moreover, Avill be that at the 80 

 and 120 foot levels, respectiA'ely. and the direction at that same le\'el 

 will be approximately 72° to 'the right of the wind. Under such 

 conditions icebergs in the deep Avater off NcAvfoundland Avould be 

 borne by the frictional current alone 72° to the right of the Avind 

 at a rate of 3.7 miles per day in the case of a 6 to 7 Avind, and at 2.5 



«« Johnston (1915, p. 40) rtmarks that he has occasionally observed a berg with one or 

 inoro high pinnacles catch the wind and sail along to leeward at the rate of 1 knot per 

 hour._ He claims that these " sailers " are capable of crossing the Gulf Stream. Quinan 

 (IJl.:., p. .ii) IS of the opinion also that the winds have a marked effect on icebergs, indi- 

 rectly by influencing the current and directly, but in a less degree, on the bergs them- 

 selves He points out tnat, although the current is the controlling factor, it is not true 

 that the wind has no effect. He .says (p. 37) : "Had northerlv winds continued, there is 

 no telling how far south this berg would have traveled, but fortunately the southerly wind 

 asserted itself and the bergs started northward with almost as much velocity as" when 

 they came south. ' ^ 



Ekmln'dolT' ^^■'"'' ^^- ^^--'^"0^ "'"1 ^"^'f'^ '1026, pp. 46-50). Most recently 



