!fe MODERN FOfcESTT ECONOMY. 



grosser pores ; and this evidently plays an additional and 

 important part, as it diminishes the flowing sheet of water 

 which is making for the river by the volume of water 

 infiltrating through the ground. And, furthermore, this 

 permeability is communicated by means of the roots to 

 the sub-soil that is to say, the layer upon which the 

 vegetable soil rests. Let one then imagine what an 

 immense quantity of water comes to be engulfed in 

 these canals, a veritable drainage by innumerable ramifi- 

 cations. 



'A very considerable diminution of the volume of a 

 flood is a consequence resulting from the diversified action 

 of the mode and power of the operations which have been 

 thus brought under consideration. This has been brought 

 prominently forward by the hydrologic experiments of 

 MM. Jeandel, Cantegril, and Belland, Gardes Generaux 

 des Forets, who made it the subject of a Memoir addressed 

 to the Academy of Sciences in 1861. Their observations 

 were made in two basins of the Meurthe, which were 

 absolutely different in regard to the superficial condition 

 of the ground. And they have proved that the co-efficient 

 of superficial flow and the co-efficient of inundating action 

 are at least twice as great in the basin devoid of wood as 

 they are in the wooded basin ; or, in terms more generally 

 intelligible, that forests reduce by at least one half the 

 chances of inundations. We cannot, without overstepping 

 the limits of the restricted outline which we have laid 

 down, enter here into an examination of the criticisms, 

 sometimes bitter and often unjust, which have been made 

 upon this remarkable and conscientious work, and of the 

 replies made in defence of it. 'Let us only say that the 

 authors of the Memoir have at least a right to claim that 

 they have formulated general laws which render an account 

 of the observations collected by them in the circumstances 

 in which they found themselves placed. That, if they had 

 been placed in circumstances different from these, they 

 might have obtained results and numbers somewhat dif- 

 ferent, is possible. But that the import of these results 



