THE " GREAT ICE AGE." 165 



breaking." Mr. Geikic illustrates this by a diagram showing 

 the ** calving" of an iceberg. 



In spite of my respect for Mr. Geikie as a geological 

 authority, I have no hesitation in contradicting some of the 

 physical assumptions included in the above. 



Ice has no such rigidity as here stated. It does possess in a 

 high degree " the property of yielding to mechanical strain 

 without rupturing." We need not go far for evidence of 

 this. Everybody who has skated or seen others skating on ice 

 that is but just thick enough to " bear" must have felt or seen 

 it yield to the mechanical strain of the skater's weight. 

 Under these conditions it not only bends under him, but it 

 afterward yields to the reaction of the water below, rising and 

 falling in visible undulations, demonstrating most unequivocally 

 a considerable degree of flexibility. It may be said that in this 

 case the flexibility is due to the thinness of the ice ; but this 

 argument is unsound, inasmuch as the manifestation of such 

 flexibility does not depend upon absolute thickness or thinness, 

 but upon the relation of thickness to superficial extension. If 

 a thin sheet of ice can be bent to a given arc, a thick sheet 

 may be bent in the same degree, but the thicker ice demands a 

 greater radius and proportionate extension of circumference. 

 But we have direct evidence that ice of great thickness actual 

 glaciers may bend to a considerable curvature before breaking. 

 This is seen very strikingly when the uncrevassed ice-sheet of a 

 slightly inclined neve suddenly reaches a precipice and is thrust 

 over it. If Mr. Geikie were right, the projecting cornice thus 

 formed should stand straight out, and then, when the trans- 

 verse strain due to the weight of this rigid overhang exceeded 

 the resistance of tenacity, it should break off short, exposing a 

 face at right angles to the general surface of the supported 

 body of ice. Had Mr. Geikie ever seen and carefully observed 

 such an overhang or cornice of ice, I suspect that the above 

 quoted passage would not have been written. 



Some very fine examples of such ice-cornices are well seen 

 from the ridge separating the Handspikjen Fjelde from the 

 head of the Jostedal, where a view of the great neve or snee- 

 fond is obtained. This side of the neve terminates in precipi- 

 tous rock-walls ; at the foot of one of these is a dreary lake, 

 the Styggevand. The overflow of the neve here forms great 

 bending sheets that reach a short way down, and then break off 

 and drop as small icebergs into the lake.* 



* See "Through Norway with a Knapsack,'' chapters xi. and xii., 

 for further descriptions of these. 



