130 



MARIOX EXPEDITIOX TO DAVIS STRAIT AXD BAFFIN BAY 



maps, which includes gradient currents only (hgs. 103, 104, 105, and 

 106) is a<lditional proof of the relative inefficiency of the wind. 



This conclusion mu.st be modified somewhat, however, when ice- 

 bergs nearino; tlie 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, iy24a, p. 80) by a berg east 

 of Newfoundland that we followed ^Vlay 20 to June 12, a period of 28 

 days, over a total distance of 220 miles. (See figs. 86 and 87.) Dur- 

 ing the first two weeks while it was large and 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 by the salinity and the tem]H'rature of the water in 

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



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 Avas toAvard the south. During the 

 }>eriod May 26 to June 13 the berg drcAv at least 120 meters (396 

 feet), proof that its underAvater body must then haA^e been under 

 the control of the dee})er northern currents. On June 13, 1924, 

 hoAvcA^er, large quantities of ice Avere calved, the main body greatly 

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

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

 formity either Avith 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 Avind. 



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

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

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

 above the sea at the other. Below Avater there Avere two large peaks 

 extending doAvnAvard 160 feet and 200 feet, respectiA^ely.*^' 



While the foivgoing measurements Avere being taken the salinity 

 and temperature of the Avater in Avhich the berg floated AAere also 

 observed. 



Salinity 



32.80 

 32.82 

 33.09 

 33.52 



Bottom. 



*' The moasurements nnder water were carried out by two small boat.*! lowering a heavy 

 weight to a designated depth, the weights being connected by a fine wire about 450 feet 

 long. Passing on either side of the berg the wire span was" pulled taut and the weights 

 lowered until the wire passed under the ice. 



