84 BOARD OF AGRICULTURE. 



manner for long periods of time. The "Tooth of Time," is 

 an expression belonging indeed to figurative literature, but one 

 also fully justified by fact. It is a tooth whose action never 

 ceases and wliose sharpness is never blunted. The grand 

 rock-ridges and peaks which make the mountains of the globe, 

 although they have held their crests aloft in flinty defiance 

 through all the periods of human history or tradition, are 

 slowly wasting under its incessant bite, and the explorer in 

 the high Alps hears from hour to hour the thunder-like noise 

 with which huge blocks of granite, loosened from the moutain- 

 tops, crash downwards. At the base of any high cliff you may 

 see a lalus of sharp-angled stones reaching half up the breast 

 of rock, unless some rapid stream of water or slow-pushing 

 glacier is there to carry them away. Our level fields are or 

 have been covered with lumps of rock, and our soil is full of 

 them, but these are not sharp edged as if just struck off by 

 a hammer-blow, but they are rounded in all their outlines ; 

 the " Tooth of Time" has not ceased to eat away at every 

 angle and corner of these tempting morsels as the teeth of 

 children gnaw at sugar plums. Nor does the work stop here. 

 As they lie out on the pasture or buried in the plow-land, the 

 same invisible tooth nibbles at every point of their surface, 

 roughening and corroding them until they are reduced to 

 dust. Even the sand-grains are ever cut smaller and finer 

 until they dissolve away from our sense of sight or feel, and 

 the long imprisoned potash and lime, the phosphates and the 

 sulphates, are released. 



It is the " Tooth of Time" which thus levels mountains and 

 crushes boulders into soil, and it is the same tooth whose in- 

 cisive workings in the soil reduce the elements of the rocks 

 to the impalpable state of food for the plant. Where circum- 

 ■stances remain the same, these changes prepare the nutriment 

 for plants at a certain regular rate, and the natural strength 

 of the soil is simply the expression of this steady development 

 of plant-food and the corresponding production of vegetable 

 matter. 



To turn now to what Mr. Lawes calls the "condition" of 

 ithe soil. Farmers are in the habit of saying, " This land is 



