TESTIMONY OF M. d'aRBOIS. 215 



" In the reserved quarter, in Maxey-sur-Vaise, the summer flow of 

 the spring of Moymout was much diminished when its basin was 

 exposed by the exploitations. The impermeable bed on which the 

 water is collected lies at no great depth, for during the season of 

 making charcoal the taste of the spring is affected by the smoke. 



" The inhabitants of the small town of Void have also noticed a 

 diminution in the summer discharge of water, on the destruction of 

 the woods subject to a right of felling which surmount the springs. 



" M. Clavery — who, for a long time, and with such enlightened 

 care, has administered Commercy, — has also made similar observa- 

 tions on the water system which supplies that town. He writes thus 

 on the subject : — 



" ' Since the exploitation of the woods situated in the basin of the 

 source called Fontaine Royale, which supplies the town, for two or 

 three months every year the inhabitants are deprived of water. 

 Almost all the springs dry up about the month of July. Even 

 before these woods were cut down this scarcity had begun to appear, 

 but only slightly, very few springs being entirely dried up during 

 great heat ; but since the exploitations near the Fontaine Royale the 

 greater number are exhausted every year.' 



" Cutting doft^n woods has a still greater influence on ponds. Thus 

 the ponds situated in the reserved quarter at Taillaucourt was full of 

 water during the growth of the neighbouring woods, but ever since 

 they were cut down it becomes dry during the summer. 



" In the same way roads which were muddy and impassable have 

 been rendered dry and good in summer by cutting down the adjoin- 

 ing woods. 



" In fine," he remarks in conclusion, " forests increase the summer 

 out-flow of the springs by preventing the ground being dried up, and 

 this influence is all the greater when the water collects on an 

 impermeable bed at no great depth." 



From these facts, and the many others which have been adduced, 

 there seems to be no room for doubt, notwithstanding the authority 

 to be attached to anything proceeding from the pen of a man like 

 M. le Marshal Vaillant, that forests exercise a great influence on 

 the water system of a district. 



But we can carry our investigations much further, and trace the 

 operation whereby trees arrest and so regulate the flow of and escape 

 of the rainfall in many of its details, and so make manifest what the 

 eftect of trees in this operation is. 



