MKTKOIlUl.OiMCAI. onSKHVATlOMB 41 «'.\11N\VATII. 26] 



of tlir trees penetrate, the degree at considerable depths to which 

 the temperature is lowered being equal to the mean «iiwi differ- 

 ence Iki wcrii the anderground thermometen in exposed sad 

 shaded soils. 



\ regards the sir, the mean temperatore deduced from the 

 maximum and minimum thermometers at the exposed station was 

 45 0- 3, and at the shaded station 1 1 '.' ; and the mean temperature, 

 as deduced from the dry bulb thermometers at U a.m. and 9 P.M. at 

 the exposed station was r> '2, and at the shaded station 44°*9. The 

 results, as determined by these two methods, closely agree, and they 

 ghre a mean temperature of the air about half a degree lower 

 under the shade of the trees than outside that shade. It is pro- 

 bable that further in the wood, at places to which the wind has 

 little aei ess, the lowering of the temperature of the air would 

 have exceeded half a degree, but additional observations would 

 be required to show this point, which has important bearings on 

 the question of the influence of forests on climate. 



