easure multiplied by 1000; the result will be the
length of line in inches necessary to show 1000 units.

For example, let us suppose that we desire a graphic scale showing
1000 yards, the scale of the map being 3 inches equal 1 mile:

Multiply 1/21120 (R. F.) by 36 (36 inches in 1 yard, the unit of
measure) by 1000,--that is,

(1/21120) x 36 x 1000 = 36000/21120 = 1.7046 inches.

Therefore, a line or graphic scale 1.7 inches in length will represent
1000 yards.

If we desire a working scale of paces at 3 inches to the mile, and we
have determined that our pace is 31 inches long, we would have
(1/21120) x 31 x 1000 = 31000/21120 = 1.467 inches.

We can now lay off this distance and divide it into ten equal parts,
and each will give us a 100-pace division.

_2nd method._ Lay off 100 yards; ascertain how many of your paces are
necessary to cover this distance; multiply R. F. by 7,200,000, and
divide by the number of paces you take in going 100 yards. The result
will be the length of line in inches which will show 2000 of your
paces.

_3rd method._ Construct a scale of convenient length, about 6 inches,
as described in Par. 1863, to read in the units you intend to measure
your distance with (your stride, pace, stride of a horse, etc.), to
the scale on which you intend to make your sketch.

For example, suppose your stride is 66 inches long (33 inch pace) and
you wish to make a sketch on a scale of 3 inches = 1 mile. The R. F.
of this scale is 3 inches/1 mile = 3 inches/63360 inches = 1/21120.
That is 1 inch on your sketch is to represent 21120 inches on the
ground. As you intend to measure your ground distances by counting
your strides of 66 inches length, 1 inch on the sketch will represent
as many of your strides on the ground as 66 is contained into 21120 =
320 strides. For convenience in sketching you wish to make your scale
about 6 inches long. Since 1 inch represents 320 strides, 6 inches
will represent 6 x 320 = 1,920 strides. As this is an odd number,
difficult to divide into convenient subdivisions of hundreds, fifties,
etc., construct your scale to represent 2,000 strides, which will give
it a length slightly in excess of 6 inches--6.25. Lay off this length
and divide it into ten main divisions of 200 strides each, and
subdivide these into 50 stride divisions as explained in Par. 1862.

=1889. Position sketching.= The following are the instruments used in
position sketching:

1. Drawing board with a