84 TALKS ABOUT THE SOIL. 



the ground many times, the soil might be readily 

 broken up, and made loose and soft for a few inches 

 deep. When and where this change began, we can 

 never know. We can only guess that this must be the 

 true history, because we find, even in modern times, 

 wooden ploughs that suggest this idea. Fig. II. is a 

 sketch of a Kooloo plough used in India in this 

 century ; and it is very like a forked stick sharpened 

 at the end of one branch, and fitted with a third piece 

 that serves as a handle. Pins are also added to hold 

 the harness of the horse or cow used to drag the 

 plough. Fig. II. also shows how the plough was 

 rudely shaped out of three pieces of wood, and how 

 it was fastened together with a wedge. Old Egyptian 

 monuments show ploughs used in that country before 

 the Christian era, that were very much like this Kooloo 

 plough. It was not till quite modern times, that the 

 plough was any thing more than a scratching-machine, 

 that merely made a shallow furrow by throwing out 

 the soil on both sides. 



In Fig. III. we have a modern American plough. 

 Let us look at it a moment. It consists of several 

 parts. First is the long beam (that corresponds to 

 the longer branch of the forked limb of the original 

 plough), the steel share, the mould-board, and handles. 

 There are also other details, as the coulter, that acts 

 as a knife to cut and separate that part of the soil 

 that is to be turned over, from the part left undis- 

 turbed ; the wheel on the beam, that causes the plough 

 to run at a certain depth in the soil ; and the clevis at 



