144 THE OLIVER PLOW BOOK 



of mould that will turn all the different soils equally well. 

 The fact that clay soils hold together means that a plow 

 to successfully turn and pulverize them must not have 

 so bluff a mouldboard as is required for turning loose, 

 sandy soils. The tendency of clay particles for holding 

 together removes the necessity for as much bluff ness and 

 curvature in the mouldboard. As soils vary from one 

 extreme to the other, so must builders make plow bottoms 

 to meet these variations. 



As a matter of fact, plow manufacturers have a large 

 variety of plow bottom combinations in order to prop- 

 erly plow soils of different textures. 



It is a peculiar fact that in the waxy soils of Texas, 

 plow mouldboards have been made of steel, iron, glass, 

 brass, aluminum, plaster of Paris, and hog hides. The 

 peculiar part is that the plaster of Paris and hog hide 

 mouldboards worked more successfully in these soils 

 than any other type of mouldboard that has been 

 invented. 



Whether the shape of a mouldboard has everything to 

 do with its scouring, assuming that it has the proper 

 degree of hardness, is a question open to debate. The 

 experiences gleaned from trying to develop a mould- 

 board that would work successfully in the waxy soils 

 of Texas developed so many sizes, styles and shapes of 

 plow bottoms that the plow bottom graveyard is full to 

 overflowing. These experiences must be regarded as 

 very strong evidence that something is required other 

 than the shape of the mouldboard and the material from 

 which it is made. 





