M. Boussingault on the Efftct of clearing Land. 85 

 the grand furnace of the earth ? And here we may call to mind 

 the sentiment of Seneca, which those who engage in o-eolocrical 

 researches should bear continually in remembrance : " ]\Iao-na 

 ista, quia parvi sumus credimus. Multis rebus non ex natura 

 sua, sed ex humilitate nostra, magnitude est."" 



Mevioh- concerning the Effect to/iich the clearing of Land has 

 in diminishing the Quantity of Water in the Streams of the 

 District. By M. Boussingault. 



Whether the labours of the agriculturist are effecting any 

 modification in the climates of the countries subjected to their 

 agency, is an interesting question which is now very generally 

 canvassed. It is moreover inquired, whether the immense 

 clearing away of woods in some districts, together with the 

 draining of morasses, which exert so much sway over the dis- 

 tribution of heat during the various seasons of the year, exert 

 likewise an influence upon the streams and rivers which water 

 the district, either by diminishing the quantity of water which 

 falls, or by inducing a more rapid evaporation from the sur- 

 face, when the wide spreading forest has been laid low, and its 

 place been suppHed by well cultivated fields. 



A variety of observations would indicate that such a change 

 has been, and is being, effected. In many localities it has been 

 thought manifest, that, for a certain number of years, the 

 streams which were employed in propelling water-wheels have 

 very sensibly diminished. In other places, many have been led 

 to conclude that the rivers have become more shallow ; and the 

 increasing extent of their beds, covered with pebbles on either 

 side, appear to attest the disappearance of a portion of their 

 waters. Finally, many abundant springs are now almost dry. 

 These observations have principally been made in valleys which 

 are surrounded by mountains ; and it has been thought appa- 

 rent, that this diminution in the quantity of the waters, has been 

 nearly coincident with the epoch when the hatchet was employ- 

 ed, without mercy or judgment, against 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 



