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PHYSICAL AND MATHEMATICAL SECTION. 

 February 27th, 1862. 



Mr. Baxendell, F.R.A.S., read a Paper " On the Relations 

 between the Decrement of Temperature on Ascending in the 

 Atmosphere and other Meteorological Elements." 



According to the theory which attributes the production of 

 Avinds and storms to upward currents of air, caused by the 

 heat liberated during the condensation of aqueous vapour 

 into clouds and rain, the rate of decrease of temperature on 

 ascending in the atmosphere ought to be less in rainy than 

 in fair weather ; and the reasonings and calculations of Dr. 

 Wm. Thomson, in his valuable Paper '' On the Convective 

 Equilibrium of Temperature in the Atmosphere," lately read 

 to the Society, point to the same conclusion ; but in a Paper 

 entitled "Remarks on the Theory of Rain," read to the Section 

 on the 29th of March, 1860, the Author gave some results 

 derived from a discussion of the Greenwich and Oxford obser- 

 vations, which seemed to militate against this theory, and 

 reference was made to the fact stated by Ksemtz and others, 

 that the diminution of temperature on ascending in the 

 atmosphere is more rapid in rainy than in fine weather. It 

 appears, however, that this fact is not generally admitted by 

 meteorologists, as the observations from which it is derived 

 were mostly of a desultory nature, and continued for only 

 short periods of time. The Author, therefore, thought that 

 a discussion of the monthly results of the observations made 

 during the years 1848-58, at Geneva and on the Great St. 

 Bernard, given by Mr. Vernon in his valuable Paper " On 

 the Irregular Barometric Oscillations " at those places, 

 might throw some light on the subject, and, at the same 

 time, serve to indicate the relations which exist between the 

 decrement of temperature and other meteorological elements, 

 a branch of meteorology which has hitherto been almost 

 entirely neglected. 



Tables are given, containing the comparisons of the 



