METEOROLOGY. 449 



that others should make similar studies as to tho preservation and 

 destruction of such stones. {Nature^ xxii, p. 104). 



Prof. F. Forel has published in the "Archives" of Geneva several 

 memoirs on the variations in the dimensions of the glacier of the Ehone- 

 and shows that very lai ge changes may be due not to any great varia, 

 tions of temperature but to small changes in the local distribution of 

 snow and rain. Again, any change in the latter affects first the thick- 

 ness of the glacier and eventually its length, but the latter effect is 

 specially felt only when the immense snow-slides that feed the upper 

 end of the glacier have after a long time worked their way down to the 

 lower end, so that the location of the end of a glacier and its thickness 

 depend largely upon the snowfall of fifty or one hundred years ago. 

 {Nature, xxy, p. 184.) 



Forel has published investigations on the phenomena of glaciers. He 

 concludes that molecular affinity is constantly operating to increase the 

 growth of the so-called crystalline grains of the glacier, at the expense 

 of the water which permeates the capillary fissures ; such grains increase 

 from the size of a small nut at the upper end of the glacier to the size 

 of a hen's eg^ at the lower end, the increase of volume being 4^ per 

 cent, annually. {Nature, xxvi, p. 89.) 



Naturen, for February, 1882, contains an account of the movements of 

 the Norwegian glaciers during the past two centuries. It would appear 

 that the vast system of Justedal glaciers have generally been retreating 

 since 1750, whereas up to that time they had been advancing rapidly. 

 In fact, in general the winters were milder during the latter half of the 

 last century. At the present time the glaciers are generally advancing 

 again. {Nature, xxv, p. 449.) 



Woeikoff" has published an interesting paper on the glacial period 

 in the last issue of the Zeitschrift of the Berlin Geographical Society 

 (Vol. XVI, fasc. 3). It is well established now that for the formation of 

 glaciers not only a sufficiently low temperature is necessary, but also a 

 sufficient supply of moisture in the atmosphere. Thus, at the Woznesen- 

 sky gold mine, which lies at a height of 920 meters and has a mean tem- 

 perature of —9'^ C., but a rather dry climate, we have no glaciers, 

 nor in the Verkhoyansk Mountains, where the mean temperature is as 

 low as — lo<^.G, and the temperature of January is — 48^.0. To show 

 these differences Dr. Woeikofif prepares a table of the temperatures at 

 the lowest ends of glaciers, and we see from his figures that in Western 

 Norway, at the end of the Justedal glacier (400 meters high), the mean 

 temperature is 4^.8 C; it is 5°.8 at the end of the Mont Blanc gla- 

 ciers (1,099 meters); 6^.8 at the end of the Karakorum glacier, in Tibet 

 (3,012 meters high), and even 10° on the western slope (212 meters) of 

 the New Zealand highlands, and 7° on the eastern slope (235 meters). 

 In other countries — as, for instance, on the Mounkau Sardyk Mountains, 

 in Eastern Siberia (3,270 meters) — the mean temperature at the end of 

 the glaciers is as low as — 10o.2, and — 2o.4 in the Daghestan Mountains 

 H. Mis. 2G 29 



