SPITZBEllGEN. — EXCURSION ON SHORE. l25 



to disperse the winter's coat of snow, where the 

 mean temperature of the hottest month in the year 

 mustj on a mountain of 1500 feet elevation or up- 

 ward, probably be below the freezing point *. Per- 

 haps the difficulty is to be thus resolved : The 

 weather in the months of June> July and August, 

 is much clearer at Spitzbergen than it is near the 

 neighbouring ice, where most of my observations on 

 temperature were made ; and, as such, the tempe- 

 rature of these months on shore must be warmer 

 than at sea, and so much higher indeed, as is re- 

 quisite for occasioning the dissolution of the snow 

 even on the tops of the mountains. And this is no 

 doubt the fact ; for, besides the increase of tempera- 

 ture produced by the prevalent clearness of the at- 

 mosphere, we may bring into the account the cir- 

 cumstance that, from the steepness of the hills, the 

 sun is always actually vertical, to one surface or other 



* The mean temperature of July in the Greenland sea, 

 latitude 78*^, as determined from a considerable series of ob- 

 servations (Appendix, No. II.), is no higher than 37°; and of 

 August about 2 degrees less ; as such, the mean temperature 

 of July on a hill 600 yards high, must be below the freezing 

 point : For 500 yards divided by 90 yards, the elevation re- 

 quisite for producing 1 degree depression of temperature, give 

 a product of 5^°, which, subtracted from 37*, the tempera- 

 ture at the level of the sea, leaves 31 ^ ", as the mean tem- 

 perature at the top of the hill, 



