ATMOSPHEROLOGY. — FOG. 441 



tion goes briskly on during the densest fogs. In 

 Newfoundland, I understand, on occasions when the 

 sun's rays penetrate the mist, and heat the surface 

 of the rocks, fish is frequently dried during the 

 thickest fogs. In July 1817, latitude 74°, when 

 the temperature of the air was 45°, Leslie's hygro- 

 meter indicated 6° of dryness, during a most intense 

 fog ; and on another foggy day, in the same month, 

 when a temperature of 40° prevailed, from 5 to 6 

 degrees of dryness was indicated, in a situation on 

 which the sun had not shone during the day. Fre- 

 quently I have observed the fog to be wetting at the 

 height of 40 or 50 feet above the surface of the sea, 

 when, on the level of the ship's deck, about 14 feet 

 high, there was no appearance of dampness. 



Fogs are more frequent and more dense at the 

 borders of the ice, than near the coast of Spitzbergen. 

 They occur principally when the mercury in the ther- 

 mometer is near the freezing point ; but they are by 

 no means uncommon with a temperature of 40 or 45 

 degrees. They are most general with south-westerly, 

 southerly, and south-easterly winds. With norther- 

 ly or north-westerly winds, they generally disperse ; 

 though, after a considerable continuance of southerly 

 winds, they sometimes prevail for a good many hours 

 after the wind changes to the northward. Fogs sel- 

 dom occur with high winds ; yet in one or two in- 

 stances, I have observed them very thick even in 

 storms. Rain generally disperses the fog ; but after 



