436 



REPORT OF THE COMMISSIONERS OF 



The percentages of moisture contained in the atmosphere, obtained by combinin| 

 the preceding tables for 1889, 1890, 189 1 and 1892, are as follows: 



7 A.M. 



7 P.M. 



Hygrometer No. 1, in open field, 

 Hygrometer No. 2, in open field, 

 Hygrometer No. 3, in forest, 

 Hygrometer No. 4, in forest, 



86 



64 



75 



75 



84 



62 



73 



73 



go 



78 



84 



84 



9 1 



76 



84. 



84 



Regarding the mean results from Nos. 1 and 2 as indicating percentages for the 

 pen field, we have the following: 



Percentages of moisture, open field, 



7 A.M. I P.M. 7 P.M. MEAN. 



85 63 74 74 



Regarding the mean results from Nos. 3 and 4 as indicating percentages of forests 

 only moderately dense, we have the following: 



Percentages of moisture, forest, 



7 A.M. I P.M. 7 P.M. MEAN. 



9 I 77 84 84 



Comparing results, open field and forest, we have excess of moisture in forest above 

 that in open field expressed in percentages: 



7 A.M. 



6 



I P.M. 

 14 



7 P.M. 

 IO 



MEAN. 

 IO 



In discussing these results in the Annual Report of the Maine State College for 

 1892, President Fernald, meteorologist to the agricultural experiment station, states 

 that it appears from the foregoing observations covering the growing period, April- 

 October, inclusive, that the excess of moisture in the forest above that of open fields 

 amounts in the morning to six per cent. ; in the middle of the day it rises to fourteen 

 per cent. ; at nightfall drops to ten per cent. ; and that the mean excess for the day is 

 about ten per cent. Hence, it is concluded that the presence of patches of forests in 

 any region exerts a marked influence on the hygroscopic conditions of the atmosphere, 

 which condition, in turn, is an important factor in the growth of vegetation. 



The foregoing conclusion by President Fernald is certainly justified, if such 

 differences exist between the percentage of moisture present in the air in the open and 

 in forest as is shown by the Orono observations. 



