MOIHTCKE AITRACTED BT XOrLD. hO 



imderdraiiied at ilie d^th of 1^ .i.'0, in the montfis cX Julv, Aogast, 

 Sep-^niMr, XoTcmber and December, and but a veiy trifling qaantity 

 in June and October ; in L ^ ! r . xerj little in May and September and 

 none in Jane, Jnlf and August. In 1 S^37 the total precipitatioa vas 

 1066.S4r millimetres ; the evaporation, as measmed by the difTerenee 

 betweei rain-£all and drainage, 733.44 millimetres : in 1868, tliese 

 qcantiries were 1032.36 ani 75-5.74 millimebes reqwctiTely. 



M. Gesanne rranazks in regard zo all the obserrataoni cited by him, 

 — " In condodon, and iriQi ereiy allowance fisr tlie smaO quantity d 

 vater vliidi is retained by the lesres, the foregoing ofaserrations 

 stzio^tlien the oaodaalrMi xhaz, nnder the same measoie of isait&D, 

 the sofl of the forest zeceiYes and retains notably more water than 

 does nnooTered groond. 



Sbct. it. — Oh, MoUtwe hang AttrcKted jVam t\e AtmotjAere, or other- 

 mse reUumd im Ike Ground hy YegOatiU Mould. 



The meteoiDlogical effects of forests are, as his been intimated, 

 someirhat complicated, and the 5t::ient of these availing himself <^ 

 mj gnid^ice may be b^innii^ t j peiceire something of tbe compli- 

 cate n in which they are icTcilved ■ t:it thas &r the nnraTeDing jf 

 differetit strands has been found to be practicable, and this operation 

 may be cazned i little finther ■* :tho" difiSeolty. 



A distinction has been drsrs-a between the effects prodnoed on the 

 groond by the shade hcgn. sanshine, and by the shelter frim drying 

 wimis afforded by trees and forests. It is nece^ary, fintiier, to 

 disriz-gn'-h betweai the eafects imidooed by ^lade and by v^etable 

 mould, which exists always, in greater or less qoantity, in forest sjH, 

 in consequence (K the decay and decomposition of Mien leaves and 

 and &nen twigs, and broken or decaying rx^tlets. 



In the soQ of a for^t there generally exists more moistare than 

 can be attributed to shade, or to shade and ihelter combined ; and 

 mni of this is attributable to the attraction of m jistore manifested 

 by this vegetaiie moold. 



By a series of iitnple experinients this fact may be demonstrated, 

 the quantity ;f mtisture ietentined, and the propcrtioc attribatable 

 to each of the ere-;ts mentioned approximately -ascertained. 



Take the --eight rfa handred grains or of a handled drams, or the 

 wd^it of a hmidred shot of nniform size, of the apparently dry soil 



