_Walking Plow._--The draft of a walking plow may be increased or diminished by the manner of hitch. It is necessary to find the direct line of draft between the work performed and the propelling force. The clevis in the two-horse doubletree, or the three-horse evener and the adjusting clevis in the end of the plow-beam with the connecting link will permit a limited adjustment. The exact direction that this line takes will prove out in question. The walking plow should not have a tendency to run either in or out, neither too deep nor too shallow. For the proper adjustment as to width and depth of furrow, the plow should follow the line of draft in strict obedience to the pull so that it will keep to the furrow on level ground a distance of several feet without guidance from the handles. In making the adjustment it is first necessary to see that the plow itself is in good working order. All cutting edges such as share, coulter or jointer must be reasonably sharp and the land slip in condition as the makers intended. [Illustration: Figure 134.--Disk Plow. Less power is required to plow with a disk, but it is a sort of cut and cover process. The disk digs trenches narrow at the bottom. There are ridges between the little trenches that are not worked.] [Illustration: Figure 135.--Three-Horse and Four-Horse Eveners. This kind of evener hitches the horses closer to the load than some others and they are easier to handle than the spread out kinds. The four-horse rig requires the best horses in the middle.] All plows should have a leather pocket on the side of the beam to carry a file. A 12-inch bastard file with a good handle is the most satisfactory implement for sharpening the cutting edges of a plow in the fields. A good deal depends on the character of the soil and its condition of dryness, but generally speaking, it pays to do a little filing after plowing a half mile of furrow. If the horses are doing their duty, a little rest at the end of the half mile is well earned. The plowman can put in the time to advantage with the file and the next half mile will go along merrily in consequence. No farmer would continue to chop wood all day without whetting his axe, but, unfortunately, plowmen often work from morning till night without any attempt to keep the cutting edges of their plows in good working order.