For whilst People liv’d on Acorns, there was no need of the Smith; such Food required no Knives for eating it, nor was it worth while to make Swords to fight for it; and without Iron the Spade could not be well hewn, or shap’d; but if it had been such as it is at present, there never was any thing comparable to it, for the true Use of Tillage. Yet the Spade could not make that Expedition, which was necessary when Tillage became general in the Fields; and therefore in time the Spade came wholly to be appropriate to the most perfect Sort of Tillage in the Garden. Then the Plough supply’d the Place of the Spade in the Field; and tho’ it could not (such as it was) till the Land near so well, yet it could till ten times more of it, and with less human Labour. Why they did not improve the Plough, so that it might also till as well as the Spade, seems owing to their Primitive Theory, which gave no Mathematical Reason to shew wherein the true Method of Tillage did consist; _viz._ in dividing the Earth into many Parts, to increase its internal Superficies, which is the Pasture of Plants. The Difference betwixt the Operation of the Spade, and that of the common Plough, is only this; that the former commonly divides the Soil into smaller Pieces, and goes deeper. How easy and natural it is to contrive a Plough that may equal the Spade, if not exceed it, in going deeper, and cutting the Soil into smaller Pieces, than the Spade commonly does, I leave to the Judgment of those who have seen the Four-coulter’d Plough. The Plough describ’d by _Virgil_ had no Coulter; neither do I remember to have seen any Coulter in _Italy_, or the South of _France_; and, as I have been informed, the Ploughs in _Greece_, and all the _East_, are of much the same Fashion: Neither is it practicable to use a Coulter in such a Plough; because the Share does not cut the Bottom of the Furrow horizontally, but obliquely; in going one way, it turns off the Furrow to the right Hand; but in coming back, it turns it to the Left[256]. Therefore, if it had a Coulter, it must have been on the wrong Side every other Furrow: And besides, as the Handle (for it has but one) always holds the Plough towards one Side, with the Bottom of the Share towards the unplow’d Land, it would cause the Coulter to go much too low when it went on the Furrow-side, and it would not touch the Ground, when it went on the Land-side. [256] _Note_, This _Eastern_ Plough always goes forward, and returns back in the same Furrow, making only one Land of a whole Field: Though it turns its one Furrow towards the Right, and the other towards the Left of the Holder; yet every Furrow is turned towards the same Point of the Compass, as when we plow with a Turn-wrist Plough.