st half
mile west of the Mason farm; then, as it crosses the contour marked
20 and a second marked 40, it runs up hill, rising to forty feet
above the valley, 900 yards east of the Mason farm. Then, as it again
crosses a contour marked 40 and a second marked 20, it goes down hill
to the Welsh farm. That portion of the road between the points where
it crosses the two contours marked 40, is the highest part of the
road. It crosses this hill in a "saddle," for both north and south of
this summit on the road are contours marked 60 and even higher.

=Captain:= Corporal Wallace, you are in Salem with a patrol with
orders to go to Oxford. There is no one to tell you anything about
this section of the country and you have never been there before. You
have this map and a compass. What would you do?

=Corporal:= I would see from my map and by looking around me that
Salem is situated at the crossing of two main roads. From the map I
would see that one leads to Boling and the other was the one to take
for Oxford. Also, I would see that the one to Boling started due north
out of Salem and the other, the one I must follow, started due west
out of Salem. Taking out my compass, I would see in what direction the
north end of the needle pointed; the road running off in that
direction would be the one to Boling, so I would start off west on the
other.

=Captain:= Suppose you had no compass?

=Corporal:= I would look and see on which side of the base of the
trees the moss grew. That side would be north. Or, in this case, I
would probably not use a compass even if I had it; for, from the map,
I know that the road I wish to start off on crosses a railroad track
within sight of the crossroads and on the opposite side of the
crossroads from the church shown on the map; also, that the Boling
road is level as far as I could see on the ground, while the Chester
Pike crosses the spur of Sandy Ridge, about a half mile out of the
village.

=Captain:= Go ahead, corporal, and explain how you would follow the
proper route to Oxford.

=Corporal:= I would proceed west on the Chester Pike, knowing I would
cross a good sized stream, on a stone bridge, about a mile and a half
out of Salem; then I would pass a crossroad and find a swamp on my
right, between the road and the stream. About a mile and a half from
the crossroad I just mentioned, I would cross a railroad track and
then I would know that at the fork of the roads one-quarter of a mile
furt