SCIENTIFIC RESULTS 133 



the ocean eiirrent and its replacement by the winds.*^** As a berg 

 melts, the increasing irregularities of its contours gi^e the wind a 

 greater and greater hold. 



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

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

 and (h) the indirect effect of the Aviiid as it tends to set np a fric- 

 tional current in the surface layers of the sea. 



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

 by a wind on the sides of an iceberg. The pure wind 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 IT miles per day. Avith a Avind force of (5 to 7 on the Beau- 

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

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

 the case of icebergs we have show^n on page 112 this varies from 

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

 tegration. The following table gives 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 disregardino- 

 the coefficient of surface friction : 



Blocky 



Rounded and domed 



Picturesque Greenland 



Pinnacled and ridged 



Last stages, winged and horned- 



^ Miles per day. 



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

 wind 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 Avater column and also several 

 other conditions greatly modify the ideal theoretical development of 

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

 bloAving 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 fricti(mal depth of 300 feet. 

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

 and 120 foot levels, respectively, and the direction at that same level 

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

 conditions icebergs in the deep Avater off Newfoundland 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 wind, and at 2.5 



^'•.Tohnston (191.5. p. 40) remarks that he has occasionally observed a berg with one or 

 moro high pinnacles catch the wind and sail along to leeward at the rato of 1 knot per 

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

 UJiij. p. rfi ) IS ot 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 IIi; points out that, although the current is the controlling factor, it is not true 

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

 a«Iv[iV/"t ')f far south this berg would have traveled, but fortunately the southerly wind 

 asseited it.self and the bergs started northward with almost as much velocity as when 

 tney came south.' '^ ^y.i'.j aa wucn 



EkmJniu'osT' *^^"'' ''^'' ^^-^^'0) ^'^*^ •'^'^"1^ '192G, pp. 46-50). Most recently 



