EVILS FOLLOWING DESTRUCTION OP FORESTS, 75 



the secondary effects of trees in arresting the flow and 

 escape of the rainfall, and thus equalising to some extent 

 the flow of rivers, is embodied in a volume entitled 

 Forests and Moisture; or Effects of Forests on Humidity 

 of Climate, pp. 212-254. 



Besides citing this, let me add that in a paper in the 

 Revue des Eaux et Forets, for April 1866, there are given 

 the following striking illustration of the effect of woods on 

 torrents : — ' The State possesses, in the department of Van- 

 cluse (writes the forest conservator, Labuissifere), a forest 

 of more than 3000 hectares, situated on the portion of the 

 mountain Luberon, nearest to the valley of the Durance. 

 This region is very much cut up, and traversed in all 

 directions by very narrow and deeply embanked ravines 

 in the midst of masses more or less dense of Aleppo pines 

 and green oaks. 



' These ravines are almost the only outlets for the trans- 

 port of wood, in consequence of the difficulties which would 

 be encountered, and the expense which would be incurred, 

 in making more practicable ones on the rapid declivities, 

 strewn with enormous masses of rock. There exists one 

 so situated, called the Ravine de Saint-Phalez. The 

 direction is from north to south, in the midst of a mass 

 of Aleppo pines in a state of growth more or less compact. 



' Its length, and for four kilometres, or from the road 

 from Cavaillon to Pertuis, to the domain of Saint-Phalez, 

 of an area of about 50 hectares, forms the bassin de ricep- 

 tion of the torrent. 



' This land is well cultivated ; there are no declivities 

 too steep for cultivation ; it comprises vineyards, meadows, 

 and arable land ; the soil is argillaceous. 



'The ravine of Saint-Phalez receives many affluents, 

 the most important of which is that of the Combe d'Yeuse, 

 which joins it near the summit, where are some hundred 

 metres of the cultivated grounds of which I have spoken. 



' The ravine de la Combe d'Yeuse is of much less con- 

 siderable length than that of Saint-Phalez ; it is scarcely 



