STATEMENT BY MARSHAL VAILLANT. 213 



Usually there is no ground harder or less permeable than that 

 formed close to the trunks of trees ; if required we can bring forward, 

 as a proof, the long and deep trenches which have lately been opened 

 on some of the Boulevards of the capital, the substitution of rich 

 vegetable mould for the exhausted and, as it were, petrified soil, and 

 finally, the drainage works intended to convey air and moisture to the 

 trees on the Boulevards. All these sufficiently prove that these roots 

 would suffer in the soil in which they are condemned to grow, and they 

 are powerless as regards the penetration of water or rain, as well as in 

 imparting theleastmeasureof permeability to the soil which stifles them. 



" Monsieur Becquerel, in support of the opinion that forests are 

 favourable to the maintenance of springs, cites two facts the impor- 

 tance of which we do not deny, but which would require a more 

 careful study before being considered incontestable. We allude to 

 the Scamander, which M. de Chouseul-Gouffier found to have dis- 

 appeared, and the invasion by the lake of Tacariqua of a large tract 

 of land formerly under cultivation. Is it quite certain that the 

 source of the Scamander has dried up, simply in consequence of the 

 destruction of the cedars on Mount Ida 1 May not the reservoir 

 which supplies this spring have been disturbed by some subterranean 

 convulsion ? Have any observations been made regarding the other 

 springs on Mount Ida 1 And as to the lake of Tacariqua may not the 

 loose soil of such localities so often disturbed by volcanic eruptions 

 have first sunk and then risen, so as to cause in the first place the 

 water to retreat from, and in the second to invade, the shores of the 

 lake f Does not the entire globe, even in its most stable portions, 

 continually present such phenomena? On the western shore of 

 Schleswig and Holstein, in the strata of the ground there are found 

 alternate layers of peat, formed by fresh water, and marine deposits, 

 which sufficiently indicate alternate rises and falls of the land. 



" To resume I agree with my honourable friend, M. Becquerel, in 

 saying that forests exercise a complex action. I add that this action 

 has never been studied, specially with regard to the desiccation of 

 the soil which they cover, and the exhaustion of the springs which 

 may be the result. On this point there is work to be done, prejudices 

 to be destroyed, and truth to be revealed." 



All that is thus advanced by Marshal Vaillant is entitled to re- 

 spectful consideration. But along with these theoretic objections may 

 be taken into consideration facts which have been cited above in 

 numbers, and at the same time the following : — 



