Extract from Thomas Jefferson to John Taylor
|Monticello Dec. 29. 1794.|
I have imagined and executed a mould-board which may be mathematically demonstrated to be perfect, as far as perfection depends on mathematical principles ... it is on the principle of two wedges combined at right angles, the first in the direct line of the furrow to raise the turf gradually, the other across the furrow to turn it over gradually. for both these purposes the wedge is the instrument of the least resistance.