246 OF TEMPERATURE CHAP. 9. 



gradual descent from the Jura into Switzerland, 

 on Monday, July 29, 1822. Aeronauts have 

 frequently become deaf for a time after rapidly 

 descending in Air Balloons, and this effect 

 seems, according to accounts, to be in some 

 measure proportionate in a degree to the height 

 to which they have ascended. 



Some writers have ascribed the above phaeno- 

 menon to the relaxation of the tympanum, but 

 to me it seems clearly referable to determination 

 of blood to the internal parts of the ear, and to 

 be a similar impulse of blood to those which 

 we find often to follow nervous irritation in 

 any part or organ. 



Rain, as is known, sometimes falls with a 

 rising Barometer ; and, when this happens, it is 

 usually followed by fine healthy weather. Some 

 philosophers have called it Rain of the recom- 

 position of the air.* And I have noticed Rain, 

 with a rising of the mercury, to be attended 

 with circumstances which seem to indicate a 

 strong positive electricity .f 



* Van Mons. Nicholson's Jour. Sept. 1809. 

 t The strong and refreshing smell, which sometimes results 

 when Showers first fall, after a long drought, is not an in- 

 variable attendant on them, even under these circumstances. 

 The highly electrified water of summer's Thundershowers 



