objection. With a good map of the farm,
showing the comparative levels of outlet, hill, dale, and plain, and the
sizes and boundaries of the different in closures, a profitable winter may
be passed,--with pencil and rubber,--in deciding on a plan which will do the
required work with the least possible length of drain, and which will
require the least possible extra deep cutting; and in so arranging the
main drains as to require the smallest possible amount of the larger and
more costly pipes; or, if only a part of the farm is to be drained during
the coming season, in so arranging the work that it will dovetail nicely
with future operations. A mistake in actual work is costly, and, (being
buried under the ground,) is not easily detected, while errors in drawing
upon paper are always obvious, and are remedied without cost.

For the purpose of illustrating the various processes connected with the
laying out of a system of drainage, the mode of operating on a field of
ten acres will be detailed, in connection with a series of diagrams
showing the progress of the work.

*A Map of the Land* is first made, from a careful survey. This should be
plotted to a scale of 50 or 100 feet to the inch,(3) and should exhibit
the location of obstacles which may interfere with the regularity of the
drains,--such as large trees, rocks, etc., and the existing swamps, water
courses, springs, and open drains. (Fig. 4.)

The next step is to locate the contour lines of the land, or the lines of
equal elevation,--also called the _horizontal lines_,--which serve to show
the shape of the surface. To do this, stake off the field into squares of
50 feet, by first running a base line through the center of the greatest
length of the field, marking it with stakes at intervals of 50 feet, then
stake other lines, also at intervals of 50 feet, perpendicular to the base
line, and then note the position of the stakes on the maps; next, by the
aid of an engineer's level and staff, ascertain the height, (above an
imaginary plain below the lowest part of the field,) of the surface of the
ground at each stake, and note this elevation at its proper point on the
map. This gives a plot like Fig. 5. The best instrument with which to take
these levels, is the ordinary telescope-level used by railroad engineers,
shown in Fig. 6, which has a telescope with cross hairs intersecting each
other in the center of the line of sight, and a "bubble" placed exactly
parallel