Agricultural and Forest Meteorology. 
57 
least on the character of the vegetable covering of the soil, where 
such exists. 
This latter branch of the inquiry is far more complicated than 
the former, and opinions differ widely as to the effect on the 
climate of a country which is produced by the presence, or the 
contrary, of woods. 
The greatest difficulty we meet with is that, as the cutting of 
an extensive forest is not a rapid operation, the full result of the 
process on climate will only be manifest after a long lapse of 
years, when the clearing is complete. Now, the variations in 
meteorological values, especially in rainfall, from year to year, 
are not insignificant, and before we reason with confidence on 
the effect of woods on climate, we must satisfy ourselves and our 
readers that we really know what are the true features of the 
climate of the district in its wooded and its cleared conditions 
respectively. 
Meteorologists and physical geographers are far too ready to 
make random assertions about the climate of foreign countries, 
and these are then quoted as if they possessed real value. 
Thus, for instance, in a very useful work on this subject of the 
influence of forests on climate,* the author says (p. 225) : " In 
Ireland and Scotland, where the great woods, from which whole 
districts received their names, have disappeared, neverthe- 
less the supply of water has not diminished : " we may fairly 
ask Prof. Ebermayer for any figures he may possess to show 
what was the rainfall of the British Isles three or four centuries 
ago! 
Nay, in a work issued last year, which shall be nameless, 
although published under high foreign authority, we meet with 
the following astounding statement : " It is at least admitted that 
in the city of Manchester, since the multiplication of factories, 
hardly a day passes without rain." Taking one year as a speci- 
men, the actual number of days with rain, with even as little 
as a hundredth of an inch, at Manchester, in 1878, was only 
193, the average number for 33 stations situated over the United 
Kingdom, but mainly in England, being 199 in the same year, 
so that the mere presence of factories had not much influence ! 
To resume. The determination of the features of the climate 
of each district is a work demanding years upon years of careful 
observation, and for this reason, when the question is put to 
meteorologists — What will be the effect of planting on the water 
* Ebermayer, ' Bie pliysikalischen Einwirhungen des Waldes auf Luft und 
Boden und seine klimatologische und hygienische Bedeutung.' (The physical 
action of forest on air and soil, and its climatological and hygienic importance.) 
Aschaffenberg : Krebs, 1873. 8vo. 
