PHYSICAL COl^^SERVATION AND EESTOEATION. 49 



fabric whicli the negligence or the wantonness of former lodgers 

 has rendered untenantable. He must aid her in reclothing: the 

 mountain slopes with forests and vegetable mould, thereby re- 

 storing the foimtains which she provided to water them; in 

 checking the devastating fury of torrents, and bringing back the 

 surface drainage to its primitive narrow channels ; and in drying 

 deadly morasses by opening the natural sluices which have been 

 choked up, and cutting new canals for drawing o£E their stagnant 

 waters. He must thus, on the one hand, create new reservoirs, 

 and, on the other, remove mischievous accumulations of moist- 

 ure, thereby equalizing and regulating the sources of atmospheric 

 humidity and of flowing water, both which are so essential to all 

 vegetable growth, and, of course, to human and lower animal 

 Hfe. 



I have remarked that the effects of human action on the forms 

 of the earth's surface could not always be distinguished from 

 those resulting from geological causes, and there is also much un- 

 certainty in respect to the precise influence of the clearing and 

 cultivating of the ground, and of other rural operations, upon 

 chmate.* It is disputed whether either the mean or the extremes 

 of temperature, the periods of the seasons, or the amount of dis- 

 tribution of precipitation and of evaporation, in any country 

 whose annals V are known, have imdergone any change during the 

 historical period. It is, indeed, as has been already observed,] 

 impossible to doubt that many of the operations of the pioneer 

 settler tend to produce great modifications in atmospheric humid- 

 ity, temperature and electricity ; but we are at present unable to 



* The indestructibility of some fonns of human construction is well exem- 

 plified by the ancient maize-fields of the American Indians, where the little 

 hillocks in which the seeds were deposited remain plainly distinguishable after 

 the lapse of centuries. The most remarkable case of this sort known to me, 

 however, is the persistence of the ancient ditches and ridges of loose earth, 

 which served as boundaries for the allotments of land to discharged veterans 

 of the Roman soldiery under the emperors. These are particularly noticed by 

 Reclus, and they are as enduring as are the verses in which Virgil complains 

 of being thus ejected from his possessions near !Mantua, by foreign legionaries 

 to whom his lands had been assigned as a military bounty. The same remark 

 may be applied to the small ancient channels of irrigation in Armenia and 

 other Eastern provinces, in fields probably abandoned even before the founda- 

 tion of Rome. 

 3 



