122 MARIOX EXPEDITION^ TO DAVIS STRAIT AND BAFFIN BAY 



This theory was first sug<;ested by Barnes as a result of his observa- 

 tions on ice formations on rivers. Anchor ice, for example, in the 

 St. Lawrence River is known to rise to the surface at the first early 

 rays of dawn. If such relatively feeble liixht waves are cai)able of 

 loosening great masses of anchor ice from its moorings, they might 

 easily play an important part in breaking up icebergs. 



Barnes (1927, p. 162) impressed with the belief that a small 

 amount of penetrating energy from the sun sets up disruptive strains 



THELASTSTAGESOF AN ICEBERG N EAR TH E SXEA MSH I P LANES 



Figure 81. — This berg, on June 1'2. 1!)2:2, in latitude 41 32' X., 

 longitude 4l»° 45' W., south of the Grand Banli in tlie northern 

 edge of the Gulf Stream, broke up conipletel.v within a few hours' 

 time. The disintegrated part, now in the form of growlers, 

 entirely melted within 12 hours, and the menace was removed 

 from the ice patrol ttroadcast. (Official photograph, interna- 

 tional ice patrol. I 



in icebergs, carried out a num})er of experiments to test the effects of 

 large (juantities of heat. During the summer of 192G (see Barnes, 

 1927a) several icebergs were boarded along the east coast of New- 

 foundland near Twillingate, and a slow-burning explosive called 

 thermit was buried to a depth of 3 feet and more in the ice. Parts 

 of a large plateau forming a major portion of one of the icebergs 

 disintegrated when a charge of 100 pounds of thermit w^as ignited. 

 Loud cracks and roars continued throughout that ni^ht and by the 



