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METEOROLOGICAL OBSERVATIONS, 



BAROMETER. 



NOVEMBER 22, 1768. A remarkable fall of the barometer all 

 over the kingdom. At Selborne we had no wind, and not much 

 rain ; only vast., swagging, rock-like clouds, appeared at a distance. 



PARTIAL FROST. 



THE country people, who are abroad in winter mornings long 

 before sun-rise, talk much of hard frost in some spots, and none 

 in others. The reason of these partial frosts is obvious, for there 

 are at such times partial fogs about ; where the fog obtains, little 

 or no frost appears : but where the air is clear, there it freezes 

 hard. So the frost takes place either on hill or in dale, where- 

 ever the air happens to be clearest and freest from vapour. 



THAW. 



THAWS are sometimes surprisingly quick, considering the small 

 quantity of rain. Does not the warmth at such times come from 

 below ? The cold in still, severe seasons seems to come down 

 from above : for the coming over of a cloud in severe nights 

 raises the thermometer abroad at once full ten degrees.* The 

 first notices of thaws often seem to appear in vaults, cellars, &c. 

 If a frost happens, even when the ground is considerably dry, 

 as soon as a thaw takes place, the paths and fields are all in a 

 batter. Country people say that the frost draws moisture. But 

 the true philosophy is, that the steam and vapours continually 

 ascending from the earth, are bound in by the frost, and not suf- 

 fered to escape till released by the thaw. No wonder then that 

 the surface is all in a float ; since the quantity of moisture 

 by evaporation that arises daily from every acre of ground is 

 astonishing. 



* hi such cases, the heat radiating from the surface of the earth is of course confined by the 

 covering of cloud, and prevented from dissipating. ED. 



