602 SELECTIONS FROM ADDRESSES. 



maintains its proper position and its proper depth, simply by 

 causing it to hold its upright position, and therefore the labor 

 of the ploughman is materially lessened. The improved Mich- 

 igan plough, as offered by Mr. Knox, establishes a new fact in 

 the art of ploughing, namely, that a plough may be so construct- 

 ed that the upper portion of the soil, by being turned over by 

 a separate share, leaving the separate portion to be elevated 

 by another, consumes less power than the removal of the 

 whole mass by a single share. It gives us all the advantages 

 of trench ploughing, if performed to an equal depth. The por- 

 tion of soil which has received the combined influences of sun 

 and air, is placed nearest the roots of plants, while another por- 

 tion requiring such influences is alternated each year, so as to 

 benefit by these actions. 



The removal of a less portion of soil at a time, subjects all 

 the particles to less pressure than if the whole mass had to be 

 removed by an amount of power passed through the lower 

 particles alone ; and this will prove particularly serviceable in 

 soils charged with clay at a few inches below the immediate 

 surface, for where so much force is applied to this clay, as is 

 consequent upon the removal of the whole mass by power 

 necessarily applied to the lower side, it will cause a compact- 

 ing of the clay, which, if ploughed when slightly too moist, 

 will require years of cultivation to again restore it to its pul- 

 verized state. Many a field has been destroyed by being 

 ploughed when too wet, thereby compacting its clayey portions. 



All the rationale I have offered in relation to atmospheric 

 influences as connected with surface ploughing, is equally 

 applicable to subsoil ploughing, and underdraining. The 

 subsoil plough is not intended to elevate the subsoil to the 

 surface, but simply to follow the surface plough propelled by 

 a separate team passing its beam along the bottom of the 

 surface plough-furrow, and disintegrating the subsoil. This 

 it does without elevating it, as it has no mould-board and 

 simply acts like a knife with a lower shoe, raising its load a 

 single inch, and suffering it to fall back in the subsoil cut, 

 loosened and opened. , Such treatment, it is true, is of no ser- 

 vice in soils surcharged with moisture. Such soils cannot be 

 benefited by subsoil ploughing until after thorough under- 

 draining ; for the stagnant condition of water in these cuts 



