1790. The straight edge, for a garden, may also serve for a plumb-rule. It is merely a slip of board with straight parallel edges and sides, of any length from four to ten feet, with the addition of a plummet for occasional use as a plumb-rule. It is used to form and prove smaller levels, between points settled, by the borning-pieces; or to prove beds or borders of even or plane surfaces. As a plumb-rule, this implement is also used to place espalier rails, temporary walls of boards, and even standard trees, upright.