CHAI'TER VI. 



GREAT PEOJECTS OF PHYSIC AX CHANGE ACCOMPLISHED OK 

 PROPOSED BY MAN. 



Ontting of Isthmuses— Canal of Suez— Maritime Canals in Greece — Canals to 

 Dead Sea — Canals to Libyan Desert — Maritime Canals in Europe — Cape 

 Cod Canal — Changes in Caspian — Diversion of the Nile — Diversion of 

 the Rhine— Improvements in North American Hydrography — Soil below 

 Rock — Covering Rock with Earth — Desert Valleys — Effects of Mining — 

 Duponchel's Plans of Improvement — Action of Man on the Weather — 

 Resistance to Great Natural Forces — Incidental Effects of Human Action 

 — Nothing small in Nature. 



In a former chapter I spoke of tlie influence of hnman action 

 on tlie surface of the globe as immensely superior in degree to 

 that exerted by brute animals, if not essentially different from it 

 in kind. The eminent Italian geologist, Stoppani, goes further 

 than I had ventured to do, and treats the action of man as a new 

 physical element altogether sui generis. According to him, the 

 existence of man constitutes a geological period which he desig- 

 nates as the cmthropozoic era. " The creation of man," says he, 

 " was the introduction of a new element into nature, of a force 

 wholly unknown to earlier periods." " It is a new telluric force 

 which in power and universality may be compared to the greater 

 forces of the earth."* It has already been abundantly shown 

 that, though the undesigned and unforeseen results of man's ac- 

 tion on the geographical conditions of che earth have perhaps 

 been hitherto greater and more revolutionary than the effects 

 specially aimed at by him, yet there is scarcely any assignable 

 limit to his present and prospective voluntary controlling power 

 over terrestrial nature. 



• Corso di Oeologia, Milano, 1873, vol. ii., cap. xxxi., § 1837 

 (584) 



