152 CLIMATE. 



sea. As we ascend above that level, the mean temperatures di- 

 minish in exposed situations ; but we have no sufficient observa- 

 tions to determine the rate of diminution. At Huggate on the 

 Wolds, which is about 500 feet above the sea, the annual mean 

 temperature is reduced from 48 0> 2 to 46 0> 5. At Harrogate, 

 which is about 300 feet above the sea, it is about the same. 



The temperature of the earth and of springs issuing from it 

 has not been sufficiently studied in Yorkshire. In my many 

 wanderings through the county I have been usually intent on 

 other matters, and have in consequence seldom been able to 

 make observations on this subject. On Mickle Fell, at a height 

 of 2000 feet, a spring was found to have the temperature of 46, 

 on the 3rd of Sept. 1851. On Ingleborough, at a height of 1900 

 feet, a spring gave 46 on the 2nd Oct. 1851. 



The temperature of the sea is another of the desiderata, in 

 treating of the climate of Yorkshire, on which scarcely any data 

 exist. 



HUMIDITY OF THE AIR. 



There is no such thing in nature as an absolutely dry atmo- 

 sphere, though in some countries rain may be entirely unknown ; 

 there is also no part of the earth's surface constantly loaded with 

 mist, though in the dreary regions of Tierra del Fuego this 

 latter condition is almost reached ; while Africa and Arabia yield 

 types of remarkable dryness. 



Rain, hail, and snow afford by their frequency, and the vertical 

 depth of water which they yield in a year or month, not so much 

 an accurate measure of the humidity of the air over the place of 

 the observation, as of fluctuations and displacements in the mass 

 of the atmosphere to the height of a few thousand feet these 

 changes being sometimes the result of causes put in action at 

 some far-distant part of the globe, and sometimes the effect of 

 local peculiarities, such as proximity to the sea, or to mountain- 

 ous lands running in given directions. 



