Largo bergs literally were reduced to fragments by a series of explosions 

 and reactions. 



Thermite has been used successfully in clearing ice jams and opening 

 leads but its use in ice has proven dangerous with at least one known 

 fatality. The theory of its use involves the high temperature of its com- 

 bustion when the thermite, an intimate mixture of powdered aluminum 

 and iron oxide, reacts to produce molten iron. The high temperature 

 gradient, though from a relatively small heat source, may set up a shock 

 wave within the berg and fracture it along its planes of internal stress. 



Barnes' methods were not attempted by the International Ice Patrol 

 due to the hazards of boarding an iceberg in the open sea. Only those 

 who have witnessed the awesome spectacle of a berg close-up can ap- 

 preciate fully that hazard. It was decided that any experiments for the 

 artificial disintegration of bergs should lay along the theories of Barnes' 

 work but, moreover, should be such as could be accomplished by an 

 aircraft, i.e., bombing. Toward this end, Headquarters, U.S. ('oast Guard 

 obtained through the courtesy of the U.S. Department of Defense 20 

 aircraft incendiary bomb clusters having high temperature character- 

 istics. Ten of these bombs weie Mk.35 Type, each weighing 700 lbs and 

 consisting of a cluster of 57 bomblets of 10 lbs. apiece with a filling of 

 2.75 lbs of PT1 mixture in a magnesium alloy body. PTl is an incendiary 

 mixture of powdered magnesium and thickened gasoline. 



The remaining 10 bombs were Type Mk.36 of similar appearance as 

 the Mk.35. These bombs weighed 975 lbs. and had a cluster of 182, 4-lb., 



Figure Hi. U.S. Coasl Guard IT •_'( 1 amphibian aircraft being armed with 1.000 

 pound incendiary bomb cluster in preparation for iceberg demolition 

 experiment. 



24 



