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THE NATIONAL GEOGRAPHIC MAGAZINE 



THE ADVANCING TERMINUS OE CHILDS GLACIER, NEAR THE NORTH EDGE, IN AUGUST, 

 I9IO, WHEN THIS PORTION WAS ADVANCING ABOUT 3^ EEET A DAY 



ter when the water is low and the river 

 weak. It is evident, therefore, that the 

 preservation of the railway bridge is due 

 to the river, the very thing which necessi- 

 tates the bridge. 



It will be most interesting to see if the 

 advance continues during the low-water 

 stage from October, 1910, to May, 191 1, 

 with gradual forcing of the river east- 

 ward, the cutting back of the river bank 

 in the unconsolidated gravels, the inter- 

 ference with stream flow and icebergs 

 discharge from Miles Glacier, and many 

 accessory phenomena. 



Grinnell Glacier, a smaller ice tongue 

 north of Childs, also began to advance 

 between 1909 and 191 o. 



ADVANCING GLACIERS IN PRINCE WILLIAM 



SOUND 



An unusually large number of glaciers 

 in Prince William Sound were advancing 



in 1910. Of these the largest is Colum- 

 bia Glacier. This ice tongue, west of 

 Valdez, is three to four miles wide and 

 25 miles or more in length. It has two 

 tidal fronts, separated by Heather Isl- 

 and, upon which the middle of the gla- 

 cier terminates. It had its last important 

 advance about 1892, as determined by 

 G. K. Gilbert in 1899, an d began the 

 present advance during or just before 

 1908. This has progressed as follows, 

 as observed by Prof. U. S. Grant and 

 the National Geographic Society's 1909 

 expedition : 



After July, 1905, to July 15, 1908, ad- 

 vance, 100 feet. 



July 15, 1908, to June 24, 1909, ad- 

 vance, 310 feet. 



June 24, 1909, to August 23, 1909, 

 advance, 70 feet. 



These observations are on Heather 

 Island. 



