ESSENTIALS OF SUCCESS 207 



But my supporting parties had another duty to per- 

 form, only a little less important than the one already 

 noted; that was to keep the trail open for the rapid 

 return of the main party. 



The magnitude of this duty is clear. The ice of 

 the polar sea is not an immovable surface. Twenty- 

 four hours — or even twelve hours — of strong wind, 

 even in the depth of the coldest winter, will set the big 

 floes grinding and twisting among themselves, crushing 

 up into pressure ridges in one place, breaking into 

 leads in another place. 



Under normal conditions, however, this movement 

 of the ice is not very great in a period of eight or ten 

 days, so that a party starting back over an outward 

 trail at the end of several days is able to knit together 

 all faults and breaks in the trail that have occurred dur- 

 ing that period by reason of the movement of the ice. 



The second supporting party, starting back several 

 days later from a point still farther on, knits together 

 the broken ends of the trail of its own division; and 

 when it comes upon the trail of the first supporting 

 party, reunites such other breaks as have occurred 

 since the first supporting party went over it on its way 

 back to land. So with the third and fourth supporting 

 parties. 



When I speak of knitting together breaks in the 

 trail, I mean simply that the passage of the supporting 

 party from that point where the trail was broken by the 

 movement of the ice to the point where the trail went 

 on again, some distance either to the east or west, 

 would itself renew the broken trail, the passage of the 

 men and dog teams packing down the ice and snow. 



