296 On the Phi/ steal Geography of the Alps, 



these fan- shaped, wide-spread masses of rubbish, are subject 

 to frequent and considerable variations in their course. 



Section III. — Meteorology of the Alps. 



The third section of the work, which we cannot afford space 

 to notice particularly, treats elaborately of the meteorology 

 of the Alps. It consists of numerous observations and experi- 

 ments on the temperature of the atmosphere, also its pres- 

 sure, moisture, prevailing winds, and composition. They found 

 the proportions of oxygen and azote the same at all heights ; 

 and that the quantity of carbonic acid increases in quantity 

 up to the height of 10,300 feet above the level of the sea. 



The following " Observations on the distribution of tempe- 

 rature in the Alps' "* will interest our readers : — 



1. The greatest irregularities, and most considerable local 

 inflexions of isothermals, are observed at the lower heights. 



2. Generally speaking, the depression of temperature is 

 also very sensible at stations in the Alps, when proceeding 

 from south to north ; and the eastern parts are colder than 

 the western. One degree of latitude produces in the plain 

 of Lombardy a difference of temperature amounting to 

 0°-7 Cent. In the interior parts of the Alps the difference 

 is 0°-5 to 0°-6 C. 



3. If we consider the isothermal lines on a longitudinal 

 profile of the Alps, we find that their forms show some con- 

 nection with the mean elevation of the different parts of the 

 Alps. The isothermals rise where the mean elevation is 

 greater ; they sink at the borders and on smaller groups. 

 This convexity of the isothermal lines in the centre of the 

 Alps is still more considerable if we represent by them the 

 temperature of the earth, since the latter is still more inti- 

 mately connected with the mass of the mountains, with the 

 insulation and radiation of the rocky substance : whilst for 

 the temperature of the air, differences of that kind are more 

 eliminated by its mobility. 



4. The vertical distances of two isothermals are the greatest 

 near the base of the Alps, attain afterwards a minimum, and 

 become in the higher parts, again a little greater. The posi- 

 tion of the minimum takes place in the northern Alps, and 

 the group of the St Gothand at nearly 6000 French feet ; in 



