THE NATIONAL GEOGRAPHIC MAGAZINE 



What Childs Glacier is do- 

 ing this vear is of the greatest 



£ interest, it may continue to ad- 



■£ vance, or the diminishing rate 

 of advance on the north margin 



^ after August n may suggest 



oo that the strongest advance is 



m over. If advance continues, 



^ will the glacier move up to and 



•J destroy the railway bridge, 



£ which is only 1,575 feet distant 



g" from the north margin, or will 



& it stop before getting there? 



J The bridge cost $1,400,000 and 

 is the key to the $20,000,000 



> railway to the copper mines. 



.5 It is absolutely certain that 



~ no corps of engineers living 

 could save the bridge and rail- 



Q way if the glacier is destined 



<u to advance that far. We have 



+j seen Hidden Glacier, in Yaku- 



•§ tat Bay, advance two miles, 



^ or over 10,000 feet, and bury 



Jcj a bench mark near the former 



•3 terminus beneath 1,100 feet of 



^ ice, and Haenke Glacier ad- 



• a vance over 5,000 feet in less 



|> than 10 months. 



^ On August 1 1 the railway 



% was about 4,500 feet from the 



o middle of the glacier, which 



0 would easily have advanced 



01 this distance between May and 

 I October, if it is moving at the 

 £ rate of 30 feet a day. If its 

 3 front had not been swept by 

 § Copper River the rapidly mov- 



> ing middle of the glacier would 

 7d pretty surely have advanced 

 % this distance, while the more 

 j*h slowly moving margin was ad- 

 73 vancing the observed 1,700- 

 £ 1,800 feet, at the rate which 

 £ increased from practically zero 

 0 in 1909 till it reached two to 

 0 eight feet a day in 1910. 



"C If the river had not had its 



& normal summer rise of six feet 



o or more the middle of the 



ojo glacier would surely have ad- 



■| vanced a good part of this dis- 



j2 tance, as it did advance 1,225 



o feet before the rise came, and 

 as it may do this fall and win- 



