AGRICULTURE AND THE INDUSTRIAL ARTS. 9 



these constituents are removed from the soil in the removal of 

 the plant of which they form a part. These indispensable sub- 

 stances of the soil compose but a very small portion of its bulk, 

 and they are not replaced by any process of nature, certainly 

 not by any process rapid enough to keep pace with the succes- 

 sion of crops. To restore the conditions of vegetation, they 

 must be replaced by man. Every crop diminishes the capacity 

 of the land for the production of another crop. This diminu- 

 tion may not be perceptible in its immediate influence upon a 

 virgin soil, rich in the necessary elements of vegetation. 

 Years, even generations, may elapse before these mineral 

 deposits shall geem to fail. Rotation in the crops will equalize 

 the drain upon the different portions of the soil. The yearly 

 agitations of the plough will bring to the roots of the plant 

 other particles of earth whose virtues have not been extracted, 

 and the steady action of the sun upon the changing surfaces 

 exposed to its rays, will develop new resources of vegetative 

 power. These and other causes will postpone the day of 

 exhaustion. That day, when it comes, is one of wrath, of ruin 

 and desolation for the work of civilized man. The imposing 

 fabric moulders, crumbles and falls. The fertile plain, once 

 waving with bountiful harvests and sustaining populous and 

 well-built cities, becomes a barren waste. The blasted fields of 

 ancient agriculture are to-day monuments of the vengeance 

 which nature wreaks upon a culture that does not compensate 

 the soil. The Roman Campagna was once the garden of Italy 

 from which the millions of the imperial metropolis drew daily 

 supplies of food. Here was the site of the luxurious country- 

 seat, the splendid villa, the estate of the Roman senator. Here 

 were purple vineyards, and rolling landscapes covered with 

 golden grain. Here, too, were temples of the gods. Now, a 

 noisome desert exhales a poisonous miasma and affords the 

 prowling robber a lurking place in its tangled growths. Only 

 here and there, where a squalid peasant has fixed his hovel, can 

 a sign of human habitation be seen. Not the Campagna alone 

 in Italy, and not Italy alone of the ancient states, exhibits the 

 ravages of the despoiling husbandman. The Etrurian coast, 

 Calabria, Asia Minor, the islands and continent of Greece, bear 

 constant testimony to the desolating power that exists in a 

 vicious agriculture. With the extension of Roman sway and 



