104 Summary of the Rain^ ^c. at Geneva. 



To this it may be answered, that the pass on St Bernard is 

 not the highest point of land in the vicinity, but rather the 

 lowest, at least of the ridge over which the road passes. Hence 

 the fall of rain, even in that elevated station, is still under the 

 influence of superior currents of air over the higher summits, 

 and may still exceed in quantity what falls on the distant plains. 

 The quantity of rain which falls at the Jbot of the mountain, 

 either on the Swiss or Italian side, I have little doubt, will be 

 found to be still greater than that which falls at the Hospital, 

 as related above. It would be very desirable, however, to ascer- 

 tain the fact ; and more especially on the side of Italy, where 

 the greatest quantity may be expected from the west winds. 



How far a ridge of hills extends its influence over a plain, in 

 regard to the weight of water precipitated, it is not easy to form 

 a decided opinion. It can scarcely be doubted, that the greatest 

 influence will be confined to two or three miles from the ridge ; 

 but some influence may be found, in all probability, at the dis- 

 tance of ten or even twenty miles or more, according to the 

 greater or less elevation of the mountains. 



It is a matter of curious observation, that the falls at St Ber- 

 nard for the four first months of the year, are all greater than 

 for any other months, and that the falls for the next four 

 months are all less than for any other, thus leaving the four last 

 months to yield about the average monthly quantity. A series 

 of twelve years can scarcely leave a doubt as to the general ac- 

 curacy of the fact. Possibly there may be some uncertainty as 

 to the quantity in regard to the snow ; the observers estimate 

 one foot in depth to be equa^ to one inch in depth of rain ; and 

 the weight of the falls for six or eight months in the year is 

 snow. 



Remark on the Barometrical Observations at St Bernard, 



The author of the summary in the Bibliotheque Universelle, 

 remarks, with surprise, that the barometer at St Bernard gives 

 the highest mean for August, and the hottest months, and the 

 lowest in the coldest months. This observation must have been 

 made without due reflection, as the cause is evident ; the stra- 

 tum of air from the height of St Bernard to the surface of the 

 earth must be lighter in summer than winter, on account of the 



