VARIATIONS OF GLACIERS/ 11.^ 



The first annual report of the International Committee on 

 Glaciers has been published,^ and gives the state of glaciers in 

 various regions of the world so far as reports have been received, 

 with references to some of the original sources of information. 

 This committee was appointed to stimulate and record observa- 

 tions on glaciers. The following is a summary of the report. 



No glaciers, except those of the Alps, have been under 

 observations long enough to yield very definite results ; but these 

 have shown a decided periodicity of about thirty-five years in 

 their size ; it is not improbable that glaciers in other regions may 

 have a similar periodicity. 



A period is the time during which a glacier goes through all 

 its changes ; it begins at a minimum, continues through the phase 

 of increase, the maximum., and the phase of decrease, and ends at 

 the following minimum. 



The Alps. — The glaciers of this chain were for the most part 

 in the phase of decrease from 1855 to 1875; since then a number 

 of glaciers have entered the phase of increase, namely : all those 

 of the Mont Blanc group, about a half of those of the Valais, 

 not more than a quarter of those of the Bernese Oberland, a few 

 in the eastern Alps, and none east of the Brenner pass ; so that 

 the phase of increase at the end of the nineteenth century has 

 been limited and not general ; and observations from 1893 to 

 1895 show that many of the glaciers which have recently been 

 advancing are again in retreat. 



Of the glaciers observed in the Eastern Alps in 1895 there 

 were about fourteen increasing, twenty decreasing, and five 

 stationary. 



' Read before the Geological Society of America at the Washington meeting, 1896. 

 ^ See this Journal, Vol. Ill, pp. 278-288. 

 3 Archives des Sciences, Vol. II, pp. 129-147, Geneva, 1896. 



378 



