130 MARION" EXPEDITIOX TO DAVIS STRAIT AXD BAFFIN BAY 



maps, which inchides «rradieiit currents only (figs. 103, 104, 105, and 

 106) is additional proof of the relative inefficiency of the wind. 



This conclusion must be modified somewhat, however, when ice- 

 bergs nearing the last stages of their career become extremely pin- 

 nacled and Avinged. An excellent example of such a case was pro- 

 vided in the summer of 1924 (see Smith. 1924a. p. 80) by a berg east 

 of Newfoundland that we followed IVIay 26 to June 12. a period of 28 

 days, over a total distance of 220 miles. (See figs. (S6 and 87.) Dur- 

 ing the first two weeks wliile it was large aud bulky (measuring 187 

 feet high and 387 feet long) it drifted in the generally accepted 

 paths of gradient currents east of Newfoundland. The conclusion 

 is corroborated b}' the salinity and the temperature of the water in 

 which the berg was floating on June 5, as follows : 



'i 



1 Bottom. 



The upper 25 meters (14 fathoms) of the water column was of 

 coastal origin subject to considerable fluctuation from the frictional 

 effect of the wind. In the deeper layers was cold Arctic water, the 

 general movement of which was toward the south. During the 

 period May 26 to June 13 the berg drew at least 120 meters (396 

 feet), proof that its underwater body must then have been under 

 the control of the deeper northern currents. On June 13. 1924, 

 however, large quantities of ice were calved, the main body greatly 

 changing form and reducing the draft. The drift froui that date 

 until the berg entirely melted on June 23 was irregular, not in con- 

 formity either with its former track or with the generally accepted 

 direction of the main current. Such an erratic course can be best 

 explained as due to control by the wind. 



This view is corroborated by measurements taken of the berg's 

 height, length, and draft on June 18 when its exposed body had a 

 pinnacle at one end 106 feet high which sloped to a mound 30 feet 

 above the sea at the other. Below water there were two large peaks 

 extending downward 160 feet and 200 feet, respectively.'^' 



While the foregoing measurements were being taken the salinity 

 and temperature of the water in Avhich the berg floated Avere also 

 observed. 



Salinity 



32.80 



32. 82 

 33. 09 



33. 52 



o Bottom. 



""The moasuremeiits uiulor water were carried out by two small boats loworins a heavy 

 weight to a desiKuated dcptli, the weights beinj; connected by a fine wire about 4.50 feet 

 long. I'assing on either side of tlie lierg the wire span was"pullcd taut and tin 

 lowered until the wire passed undci tlio ice. 



;hts 



