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why a great piece of ice riding on the swell of the open ocean should 

 turn over when struck by the almost imperceptible waves of a vessel 

 passing 100 yards or more away at a speed of 10 knots, but that is 

 what seemed to take place. Many bergs, even among the number of 

 those that project like rounded cones and hills from the sea, are so 

 finely balanced that they require but little to make them roll over. 

 One small rounded berg that was boarded in 1927 from a small boat 

 ofl the eastern edge of the Banks turned over half an hour after the 

 boarding party had departed. One smoothly rounded 1929 berg that 

 was watched for about a week southeast of the Tail was seen to roll 

 over at least once a day without any noticeable calving or breaking up. 



Assuming, however, that the situation appears to be favorable, and 

 that it is decided to attempt to mine a berg, the first problem is to get 

 upon it. Bergs too steep to be boarded without the aid of ropes can 

 doubtless in some cases be solved by shooting lines over them, hauling 

 stronger lines over their summits, and fastening floating weights such 

 as log fenders to the end of the line opposite to the boarding party. 



Spiked shoes are needed to keep from slipping, and axes for cutting 

 footholds in the hard ice are essential if any steep slopes are to be 

 ascended. The officer in charge of the boarding party must bear in 

 mind that, to the ordinary small boat risks attendant on landing 

 upon and getting picked up from a large uninhabited object in the 

 open sea must be added the danger of immersion in cold water. 



The actual cold water and boarding risks approach the vanish- 

 ing point about bergs in smooth water over 50° F. at the surface. 

 But whether a berg will calve or turn over while being approached or 

 worked upon is hard to predict. The observations of the patrol show 

 that calving south of the forty-fourth parallel is not generall}^ con- 

 fined to any particular time of the day but is liable to occur at am^ 

 time. Turning over of a berg usually occupies a number of seconds, 

 but it is liable to occur without warning, or only after the sudden 

 warning of a heavy crackling and calving. Probably in most cases 

 where a berg turns rapidly through 60° or more the boats attending 

 the working party will have the duty of pulling their charges out of 

 the water. 



Even if all parts of the berg that have towering pinnacles are 

 avoided, there is danger that a subsequent rolling movement will 

 cause ice to slide down upon persons on a berg. A movement in the 

 other direction would elevate the working party and put them in 

 danger of dropping down over cliffs to ice shelves or down into the 

 sea upon or among closely spaced growlers. 



The most stable bergs on the whole are the tabular ones. A squad 

 of infantry could be placed upon the tops of the largest of these bergs 

 and drilled at both close and extended order with comparative safety. 

 In 1929 the tabular bergs south of the forty-fourth parallel were 



