THE SIDE-HILL PLOAV. 



133 



tured by F. F. Ilolbrook & Co., Boston, one of tlie best 

 in use, and particu- Fig. 139. 



larly valuable for its 

 thorough pulveriza- 

 tion of the soil. One- 

 half of the double 

 mould-board shown 

 in the cut is used for 

 throwing the furrow IIom-ooTCs Sivitd or Side-Ml Plow. 



to the right, and the other half to the left the change 

 being eifected by passing it under the plow with a single 

 movement and hooking it in place. 



THE SUBSOIL PLOA^'. 



When the common two-horse plow alone is used by 

 farmers, it pulverizes the soil only a few inches in depth, 



Fiff. 140. 



Subsoil plowing in the furrow of a common plow. 



and its own weight and the tread of the horses on the 

 bottom of the farrow gradually form a hard crust at that 

 depth, through which the roots of plants and the moisture 

 of rains do not easily penetrate. Hence the roots have 

 only a few inches of good soil on the surface of the earth 

 for their support and nourishment ; and when heavy rains 

 fall, the shallow bed of mellow earth is soaked and injured 

 by surplus water. Again, in time of drought, this shal- 

 low bed of moisture is soon evaporated, and the plants 

 suffer in consequence. 



But, on the other hand, when the soil is made deep, it 

 absorbs, like a sponge, all the rains that fall, and gradually 

 gives off the moisture as it is wanted during hot and dry 

 seasons. For this reason, deep soils are not so easily in- 



