METEOEOLOGICAL OBSERVATIOXS AND GLACIER CHANGES. 339 



exhibit two very dry years, four dry years, and four very wet years. There 

 is no appearance of periodicity in the results of the observations, and nothing 

 which can be brought into harmony with the facts of glacier recession. 



M. Gruner, a French geologist, has endeavored to prove that there has 

 been a decrease of the temperature corresponding with that of the glaciers, 

 and to which he considers that this recession may be referred.* This he 

 does by taking quite ai'bitrarily a certain number of years out of the long 

 period during which this shrinkage has been going on, and showing that for 

 that period the temperature was below the mean. It would be easy to arrive 

 at precisely the opposite result by selecting another series of years, equally 

 with those taken by M. Gruner years of recession of the glaciers, and making 

 similar comparisons. In short his method is not a scientific one, and his 

 conclusions have no basis of fact on which to rest. 



The eminent meteorologist, Dr. J. Hann, has recently addressed a note 

 to the chief of the Meteorological Office at London, Mr. R. H. Scott, in refer- 

 ence to the subject with which we have been occupied in the preceding 

 pages. In this communication the following statement is made : " It is very 

 difficult to account satisfactorily for the retreat of the glaciers, and in fact 



ilm has not yd been done It is much to be desired that meteorologists 



should pay greater attention to this subject than they have hitherto done, as 

 it seems to me that the periodical variations in the volume of glaciers may 

 indicate more precisely {or — are a more sensitive indicator of) changes of 

 climate than the observations (? of quantity of rain-fall) made at our meteoro- 

 logical stations."! 



M. C. Dufour, who has been much engaged of late years in observations 

 of the Alpine glaciers, thus expresses himself in reference to this subject : 

 " It would, therefore, be a mistake to seek in the last few years alone the 

 cause of that retreat of the glaciers which we can now demonstrate. This 

 would, no doubt, be the right course if the retreat were caused solely by a 

 more rapid melthig, but it is quite otherwise if this cause ascends to the very 

 origin of the glacier. Now the latter is probably the case, for meteorological 

 observations do not reveal to us any notable difference between the last 

 quarter of a century and a preceding period. This is why the investigation 

 of the great retreat of the glaciers that we now witness must not be neg- 

 lected ; it is right to watch and trace it to the end in all those countries 



* Comptes Rendus, Vol. LXX.XIl. p. 632. 

 t Alpine .Tournal, Vol. IX. 1879, p. 297. 



