PLANT COVERING OF THE EARTH. 163 



lie will often notice flat pieces of stone or potsherds 

 resting on top of little columns of soil. From this 

 he may draw the conclusion that during the rain 

 the soil has washed away to a depth equal to the 

 height of the column on which the flat fragments 

 rest. In fact, they have protected the earth imme- 

 diately beneath them from the destruction which 

 the rain brings about. It is a well-known fact 

 that in all countries where the soil has long been 

 tilled, it constantly diminishes in depth and, unless 

 great care is taken, in a few centuries it passes 

 away into the streams, only remaining where the 

 surface is very level. Thus in Italy and in many 

 of the countries which have long been tilled, the 

 soils on the steeper slopes which once were fertile 

 have now so far disappeared that many extensive 

 districts are given over to sterility. 1 



1 In May, 1888, a new forest law went into effect in Italy, by which 

 the government pledged itself to pay three-fifths of the cost of reforesta- 

 tion of the mountain districts, the rest of the expense to be met by the 

 owners. In case the owners do not consent to the plan prepared by 

 the Department of Agriculture, the government is to be at liberty to 

 take the land with proper compensation and perform the work alone. 

 The estimated cost of the plan proposed is $12,000,000. Such enormous 

 expense in the near future can be spared to America at a very small 

 cost of present money and labor. If we do not soon take some more 

 effective means than at present to preserve our forests our descendants 

 will have to follow the example of Italy and spend millions, where 

 we might have accomplished better results with thousands. 



