The durability of these t
The durability of these tools were greatly improved thanks to Robert Randsome's work in the 18th century.  William Seward claimed that "no man has been as inadequately rewarded" as Jethro Wood, who introduced  a relatively modern design of this tool. In the Middle Ages, the Mediterranean scratch example of these tools  was replaced by a "heavy" one in Germany, thus decreasing the need for the cross usage of these. Thomas  Jefferson designed a mouldboard "of least resistance" for use in one of these tools. Common components of these  include the coulter and the share. Steel was introduced into the construction of these by John Deere. For 10 points,  name these devices that are used to breakup and turn the soil.
The durability of these tools were greatly improved thanks to Robert Randsome's work in the 18th century.  
plow