Notes on the Influence [No. 36, 



with the epoch wlicn the liatchet was employed, witliout mercy or 

 judgment, agaiust the woods which were widely distributed over 

 the surface of the country. 



These facts seem to indicate that in those regions where the 

 process of clearing has been extensively carried forward, less rain 

 falls than formerly. This in truth is the opinion which most 

 generally prevails upon the point, and if admitted without further 

 examination we must necessarily yield to the conclusion that the 

 clearing away of the forests diminishes the annual quantity of the 

 rain which falls upon the district. But on the other hand, even 

 allowing that all the circumstances alluded to have been satisftic- 

 torily ascertained, still it has also been observed, that since the 

 clearing of the mountains the different torrents and rivers which 

 seem to have lost a portion of their waters occasionally manifest 

 such sudden and extraordinary rises, that extensive devastations 

 are the frequent consequence. It has likewise been observed, that 

 after great falls of rain the springs which had almost entirely dis- 

 appeared, suddenly rise with unusual impetuosity, only to subside 

 with corresponding rapidity. The natural inference from these 

 latter observations, as will be at once perceived, is that we are not 

 too readily to adopt the common opinion and to admit that the 

 cutting down of the woods diminishes the annual fall of rain, for it 

 may not be at all impossible not only that the actual quantity of 

 rain has not varied, but that the quantity of water passing off in 

 the running streams may be really the same, in spite of the appa- 

 rent drought at certain periods of the year both in the rivers and the 

 springs ; and possibly the only difference will turn out to be that 

 the flowing of the same mass of water has, owing to the clearing, 

 become much more irregular. In illustration, we may remark that 

 if the small quantity of water which is found in the Rhone during a 

 certain part of the year, was precisely compensated by a sufficient 

 number of great floods, the necessary consequence would be that 

 it still conveys to the Mediterranean the same volume of water 

 which it did at the epoch anterior to the extensive clearings which 

 have been effected near its principal sources, and when, probably, 

 its mean depth was not, as it now is, subject to great variations. 

 If these were actually the case the existence of the forests would 

 be attended with this advantage that they would in some degree 



