METEOROLOGICAL OBSERVATIONS. 433 



METEOROLOGICAL OBSERVATIONS. 



BAROMETER. 



NOVEMBER 22nd, 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. 

 WHITE. 



PARTIAL FROST. 



The country people, who are abroad in winter mornings long 

 before sunrise, talk much of hard frosts 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, wherever the air 

 happens to be clearest and freest from vapour. WHITE. 



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, etc. 



If a frost happens, even when the ground is considerablyMry, 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 suffered 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. WHITE. 



