SCIENTIFIC EESULTS 



117 



wiiim Avater of 56° F., it l)e<ran to dwindle fast. calvin<r and rollin<Tj 

 continuously. The swell subsided somewhat in the afternoon, but 

 the tropical water combined with a moderate buffeting caused calv- 

 in<r to continue. The most rapid disinte2ration took place on April 

 10; loud crackings were then continually heard, and the retreat of 

 each wave exposed a surface appearing blistered, with the next wave 

 crashing away the loosened covering, to be followed by another 

 (haining and more blistering. During this stage the wind was light 

 southerly, a moderate southerly swell was running, and passing rain 

 -(| nails Avere experienced, typical of Gulf Stream weather. It was 

 api)arent by nightfall that the effects of warm air, the warm Avaters, 

 the rain shoAvers, and the constant pounding of the seas would shortly 

 (omplete the destruction of the berg, uoav rather small. It Avas not 

 surprising, therefore, next morning that we found no traces of it. 



Rapid Wastage of Icebergs in Oceanic Surroundings 



FiiiUiiE 7(!. — The lapUl rate of disintegration of this berg can be road in the excessive 

 rurliulencp of the surrounding " white water."' The seas in surging through the 

 nild section liave left the eartli vein remaining only in the two side walls. A berg 

 MS smaU as this one — 40 feet by 150 feet — reacts to the motion, riding the swells 

 like a slii]). (Photograph by Lieut. Commander X. <!. Uicketts.) 



The rate of Avastage of about 30 feet of height per day is one of the 

 most ra]:»id ones on record. 



From the foregoing and from other similar observations it is 

 clear that the rapidity Avith Avhich a berg that has drifted out of 

 jDavis Strait and reached North Atlantic Avaters around NeAvfound- 

 ■land disintegrates depends upon the temperature of the air and 

 water and on the state of the sea. A berg Avhich drifts southAvard 

 along the east side of the (Irand Bank, except late in season, is sur- 

 rounded by Avater of a temperature loAver than 35° F. (2° C.) until 

 after it passes the Tail of the Bank. Such cold surface layers are 

 primarily due to winter chilling further north, but they are partly 

 due to the presence of pack ice Avhich assists to keep the surrounding 

 water frigid and thereby alloAv the bergs to penetrate farther south. 

 Disintegration under such conditions is rather sIoav, but in the mixed 

 Avaters and in the Gulf Stream south of the Grand Bank it is accel- 

 erated. At 36° melting it quite noticeable: at 50° the changes can be 



