ING TRENCHES BY LINES.]

Suppose the drain to be ten rods long, and that it is intended to cut it
four feet deep, the natural fall being, from end to end, sufficient. We
drive a stake at each end of the drain, high enough to attach to it a
line three feet above the surface, which will be seven feet above the
bottom of the finished drain--high enough to be above the heads of the
cutters, when standing near the bottom.

Before drawing the line, the drain may be nearly completed. Then drive
the intermediate stakes, with the projecting arms, which we will call
squares, on one side of the drain, carefully sighting from one end of
the stake to the other, at the point fixed for the line, and driving the
squares till they are exactly even. Then attach a strong small cord, not
larger than a chalk line, to one of the stakes, and draw it as tight as
it will bear, and secure it at the other stake. The line is now
directly over the middle of the drain, seven feet from the bottom. Give
the cutters, then, a rod seven feet long, and let them cut just deep
enough for the rod to stand on the bottom and touch the line.
Practically, this has been found by the author, the most accurate and
satisfactory method of bringing drains to a regular grade.

Instead of a line, after the end stakes have been placed, a _boning
rod_, as it is called, may be used thus: A staff is used, with a
cross-piece at the top, and long enough, when resting on the proper
bottom of the drain, to reach to the level of the marks on the stakes,
three feet above the surface. Cross-pieces nailed to the stakes are the
most conspicuous marks. A person stands at one stake sighting along to
the other; a second person then holds the rod upright in the ditch, just
touching the bottom, and carries it thus along. If, while it is moved
along, its top is always in a line with the cross-bars on the end
stakes, the fall is uniform; if it rise above, the bottom of the drain
must be lowered; if it fall below, the bottom of the drain must be
raised. This may be convenient enough for mere inspection of works, but
it requires two persons besides the cutters, to finish the drain by this
mode; whereas, with the lines and squares, any laborer can complete the
work with exactness.

Another mode of levelling, by means of a mammoth mason's level, with an
improvement, was invented by Colonel Challoner, and published in the
Journal of the Royal Agricultural Society. It may appear to some perso