32, 



discussed in detail in the section dealing v/ith 



station #4. The experiments were carried on this 



tree from July 4th to July 8th, 1921 at a height of 



12«2meters;from July 8th to July 14th, 1921, at 7.6 



meters; and from July 14th to July 22nd, 1921, at 



1*2 meters from the ground, At each of these altitudes 



the instruments were placed on the south, northeast 



and northwest sides, 



He 

 It is practically impossible at present time 



to measure some climatic conditions with absolute 

 prcision, However, methods adapted to experimentation 

 in the field were employed which enabled the writer 

 to obtain data of sufficient accuracy for our purpose 

 to make the results significant, To measure the intensity 

 of the light the writer employed tie Wynne ITiotographic 

 Exposure Meter which was read at each station on the 

 tree, The readings were compared with those obtained 

 in the open, When the instrument was exposed in the 

 open field at noon for five successive days in July 

 under the same conditions, it took about 1,5 seconds 

 to change the paper to the standard col or, It was 

 then decided to use 1,5 as the standard or maximum 

 light intensity, All the other readings were obtained 

 by placing the instrtunent against the tree and 

 recording the time it took the light to change the 

 col r of the photographic paper, These readings were 

 computed as percentages of the intensity of the light 

 in the ppeni^ 



