16 Dr Davy's Meteorological Observations. 



owing to the great stillness of the air, after its temperature 

 had been reduced below the point of congelation, much after 

 the manner of water confined in small tubes at rest, on 

 which, without freezing, the temperature has been brought 

 as low as 20° and 17°. 



6. Fog, though most generally produced under the circum- 

 stances above mentioned, sometimes appears under the con- 

 trary circumstances ; that is, when the air is warmer than 

 the surface over which it is incumbent, or comes in contact 

 with, whether of water or rock. In the instance of mountain 

 tops, the observation is of the oldest. Homer speaks of the 

 moist south wind wrapping the mountains in mist. The 

 approach of the same wind at Constantinople is known by 

 the appearance of a low bank of mist on the sea of Marmora, 

 the waters of which are considerably colder than the Medi- 

 terranean. Instances of the same kind have been observed 

 over some of the great rivers of America. I may notice a 

 particular instance which I witnessed here on the 6th of last 

 January. It was about ten o'clock in the moi-ning. after 

 heavy rain, when the air was 47° and very moist, and the 

 temperature of Grasmere and Rydal lakes at or near the 

 freezing point, the latter having been almost entirely frozen 

 during the preceding month, and the former in part. Whilst 

 the mid-air was pretty clear, the mountains and many of the 

 higher hills were hid in mist, and a distinct low mist was 

 seen spread over a good part of the two lakes, variously 

 figured. Over Rydal Lake, nearly in its middle, it had 

 assumed the figure of the cross, from the intersection of two 

 streaks. It was almost a perfect calm ; the mi.st, indeed, 

 here and there, was in slight motion, whilst the water was 

 unruffled, and it continued no longer than it was calm ; 

 shortly a gentle breeze sprang up, and the mist from the 

 surface of the lakes was immediately dissipated. 



7. In conclusion, I shall notice briefly a few other peculiari- 

 ties of climate of the lake district. Though a larger quantity 

 of rain falls here than in most parts of England, yet the num- 

 ber of rainy days is not proportionably great ; the showers 

 are heavy, and occur about as often by night as by day. 

 The following numbers shew this, being a statement of the 



