_Resp._ Every jot as easily as with one Coulter: For, before the Furrow
is raised by the Share, it lies fast, and makes a sufficient Resistance
equally against the Edges of all the Coulters; tho’, after it be raised
and loose, it yields and recedes every way, except downwards; so that
it cannot be cut by any Edge, but such as attacks it perpendicularly
from above, as that of the Spade does.
Farm. _This seems to me reasonable; and, having very lately heard talk
of this Plough, I would gladly know more of it._
_Resp._ The Furrow, being cut into Four Parts, has not only Four times
the Superficies on the Eight Sides which it would have had on Two
Sides; but it is also more divided cross-ways; _viz._ The Ground-wrest
presses and breaks the lower (or Right-hand) Quarter; the other
Three Quarters, in rising and coming over the Earth-board, must make
a crooked Line about a Fourth longer than the strait one they made
before moved; therefore their Thinness not being able to hold them
together, they are broken into many more Pieces, for want of Tenacity
to extend to a longer Line, contrary to a whole Furrow, whose great
Breadth enables it to stretch and extend from a shorter to a longer
Line, without breaking; and, as it is turned off, the Parts are drawn
together again by the Spring of the Turf or Swerd[258], and so remain
whole after Plowing. Thus the Four-coultered Plow can divide the
Soil into above Twenty times more Parts than the common Plough; and
sometimes, when the Earth is of a right Temper betwixt wet and dry, the
Earth-board, in turning the Furrows off, will break them into Dust,
having more Superficies than is made by Four common Plowings; and it is
impossible there should be any large Pieces amongst it.
[258] A swerdy Furrow cut off by only one Coulter, being whole, is
apt to stand up on its Edge, or lie hollow; and then, being open to
the Air, it does not rot; but when it is cut by several Coulters,
it has not Strength to support itself, it falls down, lies close to
the Earth under it, and, excluding the free Air from the Turf, it
soon becomes rotten. And for killing the Turf of swerdy Land is the
chief Use of the Four-coultered Plough: For doing of which there is
this Advantage, that as in a whole Furrow there are often Strings of
Couch-grass, Three or Four Feet long; but, when cut by this Plough,
there is scarce a String left of one Foot long: And these Strings
being apt to send out Roots from every Knot or Joint, the shorter
they are cut, the more they will be exposed to the Air and Sun, which
will kill them the sooner.
Now, what a prodigious Advantage must the Influences of the Atmosphere
have upon these small Parts, for making a further Division of them!
Frost, Water, Drought, and nitrous Air, easily penetrate to their very
Centers, which cannot in the largest of them be more than one Inch and
a Quarter distant from their Superficies. This Advantage, with a few
subsequent common Plowings, performed in proper Seasons, resolves the
Earth almost all to a Powder. The Swerd, some being immersed or buried
and mixed among so great a Proportion of Mould, is soon rotten and
lost; some of the Swerd lying loose a-top, the Earth presently drops
out of it; and then the Roots are dried up, and die. Thus is the whole
Staple of the Ground brought into perfect Tilth in a very short time
beyond what the Spade ever does in such swerdy Land.