It remained for Jethro Tull of the _Horseshoeing Husbandry_ to unloose in England the long spell of the magic of Virgil's poetry upon practical agriculture.] [Footnote 84: The Julian calendar, which took effect on January 1, B.C. 45, had been in use only eight years when Varro was writing.] [Footnote 85: Schneider and others have attempted to emend the enumeration of the days in this succession of seasons, but Keil justly observes: "As we do not know what principle Varro followed in establishing these divisions of the year, it is safer to set them down as they are written in the codex than to be tempted by uncertain emendation." I have accordingly followed Keil here.] [Footnote 86: The practice of ridging land seeded to grain was necessary before the invention of the modern drill. Dickson, in his _Husbandry of the Ancients_, XXIV, argues that, while wasteful of land, it had the advantage of preventing the grain from lodging. Walter of Henley, who followed the Roman methods by tradition without knowing it, advises with them that to be successful in this kind of seeding the furrow at the last ploughing of the fallow should be so narrow as to be indistinguishable. "At sowing do not plough large furrows," he says, "but little and well laid together that the seed may fall evenly: if you plough a large furrow to be quick you will do harm. How? I will tell you. When, the ground is sown then the harrow will come and pull the corn into the hollow which is between the two ridges and the large ridge shall be uncovered, then no corn shall grow there. And will you see this? When the corn is above ground go to the end of the ridge and you will see that I tell you truly. And if the land must be sown below the ridge see that it is ploughed with small furrows and the earth raised as much as you are able. And see that the ridge which is between the two furrows is narrow. And let the earth, which lies like a crest in the furrow under the left foot after the plough, be over-turned, and then shall the furrow be narrow enough."] [Footnote 87: Farrago was a mixture of refuse _far_, or spelt, with vetch, sown thick and cut green to be fed to cattle in the process now called soiling. The English word "forage" comes from this Latin original.]