THE FOREST AS A CONDITION. 65 



fall within and without the forest. The difficulty 

 of finding stations within and without the forest 

 which differ in no other respects than the forest 

 cover, excluding all topographic and other influ- 

 ences upon meteorological phenomena, is well-nigh 

 insurmountable. 



Finally, whatever we may be able to do in ascer- 

 taining the single meteorological data that give us 

 an insight into the differences regarding these single 

 elements under varying conditions, the difference 

 in their combined effect, which we know as climate, 

 still requires the application of a philosophical mind 

 to the interpretation of the data. Hence we find 

 that not only are the collected data often discord- 

 ant, but the same data have been used by students 

 of the question both to assert and to deny proof of 

 the existence of forest influences. In other words, 

 the problem is too complicated for our present 

 means and methods to be settled by the mathe- 

 matical method. 



We are, therefore, for the present, thrown back 

 upon the method of general observations in the field 

 and the application of reasoning from well-known 

 physical laws, for this is one of those problems 

 which withdraw themselves from exact mathemati- 

 cal treatment now, and we must rely upon empiri- 

 cism until we have further advanced in developing 

 the means and methods of meteorological inquiry. 



The immaterial influence of the forest is claimed 

 to extend in at least four or five more or less sepa- 



