Action cif the Atmosphere upon neicly-deepcned Soil. 413 



Temperature 

 I of Air 

 I in the Shade. 



Ellon, Aberdeenshire ; 20 feet 

 above sea-level, and 5 miles in- 

 land ; 17 Feb., 1S55 .. .. 



Glasgow ; 14 Jan., 1780, at 6 A.M. 



llothiemurcus, Inverness, Feb., I 

 1823 / 



Strachan, Kincardineshire; 200] 

 feet above sea-level, and 1.5> 

 miles inland ; 17 Feb., 1855 ..] 



Siberia, lat. 58° 



Melville Island 



Nova Zembla 



On the Kolyma, in Asia, lat.'i 



68= 32'; 8 Jan., 1821 .. ../ 

 Arctic regions of North America,) 



lat. 05= / 



Fort Reliance 



Head of Smith's Sound, Arctic! 

 regions of North America ; Feb.. ' 

 1851 



" Fahr. 

 -12- 



-14' 

 -15- 



-15- 



-40" 

 -55- 

 -38-7 



-53-3 

 — 57' 

 -70' 



-70* 



Authority. 



The writer. 



Dr. Wilson, Phil. Trans., 1780. 



Ed. Phil. Joum., viii. 39C. 



'Rev. A. M'Connochie in a letter 

 to the writer. Temperatnre was 

 three times below zero in this 

 same month. 

 Pallas. 



Sir W. E. Parry. 

 Encyc. Brit., 8th ed., iii. 737. 

 /Ditto, stated to be greatest cold 

 ( in Asia. 



Sir J. Franklin. 



JCapt. Back, Travels in Arctic 

 \ Regions, p. 631. 

 I Dr. Kane, of the U. S. Navy, 

 j Chloric ether froze, and 57 dogs 

 j perished under symptoms of 

 \ hydrophobia. 



Pouillet calculates that if the sun's action were not felt u})on 

 our globe, the temperature of the surface of the ground would 

 throughout be uniform at — 128° F. 



As the disintegrating effects of temperature are due principally 

 to frost and the variations or range of heat to which the earth is 

 exposed, it is necessary to look even [more closely at the degrees 

 of cold to which the soil may be subject than we have done to the 

 amount of heat. This we shall find is often many degrees lower 

 than the temperature of the air a few feet above it; knowing, 

 however, what that is likely to be, we shall be the better able to 

 judge how low the temperature of the soil may be liable to fall, 

 as few meteorological observations are recorded concerning the 

 latter. 



The following Table (p. 414) sliows the extreme heat and cold 

 and range of the thermometer in the shade at various places on 

 the earth's surface. 



From the effects of radiation and cvaporati(m, the surface-soil 

 is often many degrees colder than the atmosphere at the height 

 thermom'-ters are usually hung (4 to 5 feet), and this is the case 

 even in winter. Thus Dr. Patrick Wilson, of Glasgow, during 

 the severe frost of January, 17^0, found in the declivity of a 

 garden, during a clear starlight night, a thermometer laid on the 

 surface of the snow stood from 8^ to 10^ lower than when sus- 

 pended at the height of a few inches. 



VOL. XVII. 2 F 



