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that has fallen is the same on both sides, and yet the ditches by the roadside along the 

 edge of the forest will be still filled with water, proving the infiltration going on from the 

 wooded soil, while, already for some time, those on the other side, adjoining the cleared 

 fields, will have been dry, after having served their purpose by a sudden flow. The ditch 

 on the left will have emptied itself in a few hours of all the water, which the one on the 

 right will take some days to convey to the bottom of the valley. 



"Direct effect of Forests Illustrated: — To those examples we may add another which 

 appears to ua to be characteristic. It is due to the observations of Mr. Oantegril, sub- 

 inspector of forests, and was communicated by him to the Ami des Sciences. 



" Upon the territory of the commune of Labrugni^re there is a forest of 1,834 

 hectares, (4,524 acres), known as the forest of Montant, and owned by the commune. It 

 extends northward on the Montagne-Noire, and the soil is granitic with a maximum alti- 

 tude of 1,243 meters, and a slope of from fifteen to sixty in one hundred. A little water- 

 course, the Caunan brook, rises in this forest and drains the waters of two-thirds of its 

 surface. At the entrance of the forest, and along this brook, will be found several fulling 

 mills, each requiring eight horse-power, and moved by water-wheels which work the 

 beaters of the machines. 



" The commune of Labrugniere had long been noted for its opposition to the forest 

 regulations, and the cutting of wood, together with the abuse of pasturage, had converted 

 the forest into an immense waste, so that this great property would hardly pay the cost 

 of guarding it, and afltbrd a meagre supply of wood for its inhabitants. 



" While the forest was thus ruined and the soil denuded, the waters after each heavy 

 rain swept down through the valley, bringing with them great quantities of gravel, the 

 debris of which still encumbers the channel of this stream. The violence of these floods 

 was sometimes so great that they were compelled to stop the machines for some time. 

 But in the summer time another inconvenience made its appearance. Little by little the 

 drought extended, the flow of waters became insignificant, the mills stood idle, or could 

 be run only occasionally for a short time. 



" About 1840, the municipal authorities began to inform their population relative to 

 their true interests, and under the protection of a better supervision, the work of re- 

 planting has been well managed, and the forest is to-day in successful growth. 



"In proportion as the replanting progressed, the precarious use of the mills ceased, 

 and the regulation of the water-courses was totally modified. They now no longer swelled 

 into sudden and violent floods, compelling the machines to stop ; but the rise did not be- 

 gin until six or eight hours after the rains began. They rose steadily to their maximum, 

 and then subsided in the same manner. In short, they were no longer obliged to stop 

 work, and the waters were always enough to run two machines, and sometimes three. 



" This example is remarkable in this, that all the other circumstances had remained 

 the same, and therefore we could only attribute to the reforesting the changes thstt oc- 

 curred, namely, diminution of the flood at the time of rain, and an increase in its flow 

 during common times. 



"We may readily from the preceding account for the part which forests act in heavy 

 and long-continued rains as to the floods then produced. Before reaching the soil and 

 being completely absorbed, the rain must pass through the dome of verdure formed by 

 the leaved, which they wet, thus causing the first appropriation of the waters. Then we 

 must add the results of great permeability of wooded soil, and the great absorption of 

 which the humus of forests is capable, so that until these demands are supplied no water 

 can run from the surface. 



"The flow will be slower and with less destructive force than in cleared fields, on 

 account of the obstacles of every kind which the liquid mass meets in its course, so that 

 it will not reach the bottom of the valley until after the rain which fell in the lower parts 

 shall have been discharged." 



" Review of M. ValUs' Booh : — In a very remarkable work entitled, " Btude sur les 

 inondations, lev/rs causes et leurs effects," published in 1857, M. Valle an engineer oi pants 

 et chaussees contradicts the efficacy of reforesting as a means of preventing inundations. 



