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monthly differences of temperature between the two stations, 
with the mean temperature, rain-fall, amount of barometric 
oscillation, and height of the barometer. 
The final results derived from these comparisons may be 
stated as follows : — 
1 . On the average of the year a decrement of temperature 
below the mean is accompanied by a rain-fall and amount of 
barometric oscillation below the mean, and by a mean tem- 
perature and barometric pressure above the mean. 
2. A decrement of temperature above the mean is accom- 
panied by a rain-fall and amount of barometric oscillation 
above the mean, and by a mean temperature and barometric 
pressure below the mean. 
3. A decrement of temperature above the mean for the 
season is due to a cooling of the higher strata of the atmo- 
sphere, and not to a heating of the lower strata. 
4. The production of rain is attended with a diminution of 
the general temperature of the atmosphere, the diminution 
being greater in the higher than in the lower strata. This 
result, therefore, agrees with that which the Author had 
previously derived from a discussion of the Greenwich and 
Oxford observations ; and it indicates clearly the influence of 
a cooling agency sufficiently powerful to neutralise completely 
the effects of the heat supposed to be liberated during the 
condensation of aqueous vapour into rain. 
The Author remarks that from the relations established by 
this investigation it may be concluded that in a mass of air 
moving from a higher to a lower latitude and acquiring an 
increase of temperature, the change of temperature is more 
rapid in the lower than in the higher strata ; while on the 
contrary, in a mass moving from a low to a high latitude and 
losing heat, the change is most rapid in the upper strata. It 
also seems probable that one of the essential conditions in the 
formation of a rotatory or cyclonic storm is a greater differ- 
ence of temperature than usual between the successive strata 
of the atmosphere at the point where the storm originates. 
