VI 
PREFACE. 
try as exerted upon Animal and Vegetable Life, upon the 
Woods, upon the Waters, and upon the Sands; and to these 
I have added a concluding chapter upon Probable and Possi¬ 
ble Geographical Revolutions yet to be effected by the art of 
man. 
I have only to add what, indeed, sufficiently appears upon 
every page of the volume, that I address myself not to professed 
physicists, but to the general intelligence of educated, observ¬ 
ing, and thinking men ; and that my purpose is rather to make 
practical suggestions than to indulge in theoretical specula¬ 
tions properly suited to a different class from that to which 
those for whom I write belong. 
GEORGE P. MARSH. 
Deceniber 1, 1863. 
