PLOW BOTTOM METALS 



133 







This piece of chilled metal was buried eight years. The rusty surface 

 was scratched away with the back f a k n if e blade, revealing a perfectly 

 smooth and unfitted surface beneath. 



The peculiarity 

 of the way each 

 metal wears is 

 plainly discerni- 

 'ble. 



The points of 

 these shares are 

 illustrated on 

 page 136. 



