erent strata these should be each removed
separately, and the depth and positions of objects noted.

4. Methods of Planning.

Though we cannot here give full technical details of all the methods
for plans and surveys, it will be useful to state the scope of each
method, so that they may be kept in mind, and whichever is best
suited to the individual and his work may be provided for.

1. Plain pacing.
After pacing lengths of a few hundred feet, up and down hill and
flat, tape the distances, and learn true value of pace. Careful
pacing can be done to one or two per cent. of the whole; and properly
used, in triangles, may give a useful plan.

2. Pacing and compass.
This covers large spaces quickly, but the compass is less accurate
than the pace.

3. Tape.
Lines of taping must be well planned, with triangle ties to secure
the angles. Pulling up straight is difficult in a wind, especially on
broken ground, and one per cent. error is quite possible then. When
working alone peg the tape down by the ring, or round a stone.

4. Tapes and cross lines.
Stretch two strings crossing squarely on the ground: fix the square
by laying a squared drawing block below and looking at strings over
it. Two helpers each hold a tape, zero on a string, and the two tapes
are held together by the observer and read off, giving the distance
to each string; this is to be plotted at once on squared paper, and
the plan is completed in detail as it progresses, without any note-
book or later plotting. The helpers must be capable of holding the
tape square to the string. Good for sites up to two hundred or three
hundred feet.

5. Plane table.
Excellent for some ground, where objects are visible from a distance:
otherwise it requires a marker put up at every point to be fixed.
Cumbrous to carry, much slower than 4.

6. Box sextant, used as giving angular accuracy to any of the
foregoing; most useful with taping, and in following.

7. Sextant and three points.
The most rapid accurate method is to adopt three points visible all
over the ground (as trees or chimneys) or set up three markers. Find
shape and size of this triangle. Then at any point take two angles
visible between the points, and this fixes position of observer. A
large site may have forty points fixed in two hours thus to about 1
in 1000. For detail and plotting see Petrie, _Methods and Aims in
Archaeology_.

8. Theodolite.
For the most accurate work a theodolite is u