Tillage, too, has its own particular rules[356]—Never touch the ground while it is wet and cloggy; plough with all your might; loosen the ground before you begin to plough. This method has its advantages, for by turning up the clods the roots of the weeds are killed. Some persons recommend that in every case the ground should be turned up immediately after the vernal equinox. Land that has been ploughed once in spring, from that circumstance has the name of “vervactum.”[357] This, too, is equally necessary in the case of fallow land, by which term is meant land that is sown only in alternate years. The oxen employed in ploughing should be harnessed as tightly as possible, to make them plough with their heads up; attention paid to this point will prevent them from galling the neck. If it is among trees and vines that you are ploughing, the oxen should be muzzled, to prevent them from eating off the tender buds. There should be a small bill-hook, too, projecting from the plough-tail, for the purpose of cutting up the roots; this plan being preferable to that of turning them up with the share, and so straining the oxen. When ploughing, finish the furrow at one spell, and never stop to take breath in the middle. It is a fair day’s work to plough one jugerum, for the first time, nine inches in depth; and the second time, one jugerum and a half—that is to say, if it is an easy soil. If this, however, is not the case, it will take a day to turn up half a jugerum for the first time, and a whole jugerum the second; for Nature has set limits to the powers of animals even. The furrows should be made, in every case, first in a straight line, and then others should be drawn, crossing them obliquely.[358] Upon a hill-side the furrows are drawn transversely[359] only, the point of the share inclining upwards at one moment and downwards[360] at another. Man, too, is so well fitted for labour, that he is able to supply the place of the ox even; at all events, it is without the aid of that animal that the mountain tribes plough, having only the hoe to help them.[361] The ploughman, unless he stoops to his work, is sure to prevaricate,[362] a word which has been transferred to the Forum, as a censure upon those who transgress—at any rate, let those be on their guard against it, where it was first employed. The share should be cleaned every now and then with a stick pointed with a scraper. The ridges that are left between every two furrows, should not be left in a rough state, nor should large clods be left protruding from the ground. A field is badly ploughed that stands in need of harrowing after the seed is in; but the work has been properly done, when it is impossible to say in which direction the share has gone. It is a good plan, too, to leave a channel every now and then, if the nature of the spot requires it, by making furrows of a larger size, to draw off the water into the drains.