The Earth as Modified by Human Action

George P. Marsh is the author of The Earth as Modified by Human Action, a new edition of Man and Nature. The preface says the object of the volume is to indicate the character and, approximately, the extent of the changes produced by human action in the physical conditions of the globe we inhabit. The preface lists a further aim, to point out the dangers of imprudence and the necessity of caution in all operations which, on a large scale, interfere with the spontaneous arrangements of the organic or the inorganic world.

Under the heading Measurement of Man's Influence, the text says the exact measurement of the geographical and climatic changes hitherto effected by man is impracticable, and that we possess the means of only qualitative, not quantitative analysis. A note in the text says the late Imperial Government sold about 170,000 acres of woodland between 1852 and 1866, both inclusive. The text names Bremontier as experimenting, without any knowledge of what was doing in Denmark, upon the cultivation of forest trees on the dunes of Gascony.