METEOROLOGICAL OBSERVATIONS IN GLACIER REGIONS. 337 



twenty years. Back of 1826 Plantamour did not think it best to go, on 

 account of possible errors in the observation.* 



If, then, the shrinking of the gLaciers of the Alps which has been going 

 on during the past fifty years is a phenomenon resulting from a marked 

 disturbance of the climatic conditions of that region, it could hardly have 

 escaped the close investigation of this eminent physicist and meteorologist. 

 On examining; his work, however, we find nothiui;: which will throw any 

 light on the question of this diminution, neither does the author himself 

 suggest anything of the kind. The mean temperature of the fitly years, 

 1826-75, was found to be 9°.345(C.). The greatest variations from this 

 were in 1834 and 1801 ; the former year was the hottest, the latter the 

 coldest of the fifty years, the average temperature for those years respec- 

 tively being 10°. 99 and 7°. 85, a difference of a little more than three degrees. 

 The results, on the whole, show no perceptible increase or decrease of mean 

 temperature during the five decades. The mean of the years 1871-75 only 

 varied about two-tenths of a degree from the grand mean for the fifty years. 

 There has been more than once a series of warmer followed by one of colder 

 years, but no regular recurrence or law of periodicity has been detected, 

 neither can any connection be discovered between these oscillations of tem- 

 perature and the receding of the glaciers. From 1826 to 1834 there was an 

 exceptionally warm period, or seven years above the average with only two 

 cold ones ; this was succeeded by a cold cycle, extending from 1835 to 1860, 

 with twenty-two cold years and only four warm ones. Then again came a 

 ■warm period, with thirteen warm years to two cool ones. In all this we see 

 nothing to justify a constant diminution of the glaciers during the whole of 

 the fifty years, at least so far as temperature is concerned. 



If, again, we turn to the statistics of precipitation, or of the fall of rain 

 and snow, we find no more satisfactory grounds for expecting any diminution 

 of the glaciers than are afforded by the temperature figures. The mean 



mm 



annual precipitation, at Geneva, for the yeai's 1826-75 was 815.93, and the 

 means of the last two pentads, 1866-70 and 1871-75, were almost exactly 



mm mm 



the same as the grand mean, namely, 815.62 and 814.40. The means of the 

 two pentads, 1856-60 and 1861-65, were decidedly lower than this, being 



* " Je n'avais pas utilise dans cette recherche toiites les observations meteorologiques faites, soit i Geneve, soit 

 dans les environs, mais seulement celles qui, par la nature de I'exposition des instruments, et par les soins apportes 

 dans le controle et la verification des indications fournies par eux, pouvaient donner des resultats comparaUes 

 entre eux et d'uue exactitude suflisante." Nouvelles Etudes, etc. : Introduction. 



