isades give
some shelter from fire and the openings should be made as large as
possible without letting men through. If defended from the flank, they
may be closer, say 3 to 4 inches apart. The top should be pointed. A
strand or two of barbed wire run along the top and stapled to each
post is a valuable addition.

Palisading is best made up in panels of 6 or 8 feet length, connected
by a waling piece, preferably of plank, otherwise of split stuff. If
the tops are free, two wales should be used, both underground. If the
tops are connected by wires, one will do.

Palisades should be planted to incline slightly to the front. As
little earth should be disturbed in digging as possible, and one side
of the trench should be kept in the desired plane of the palisade. If
stones can be had to fit between the posts and the top of the trench,
they will increase the stiffness of the structure and save time in
ramming, or a small log may be laid in the trench along the outside of
the posts. Figs. 3 and 4 show the construction and placing of
palisades.

[Illustration: Fig. 3]

[Illustration: Fig. 4]

=1178. A fraise= is a palisade horizontal, or nearly so, projecting
from the scarp or counterscarp. A modern and better form consists of
supports at 3 or 4 feet interval, connected by barbed wire, forming a
horizontal wire fence. Fig. 5.

[Illustration: Fig. 5]

=1179. Cheveaux de frise= are obstacles of the form shown in Fig. 6.
They are usually made in sections of manageable length chained
together at the ends. They are most useful in closing roads or other
narrow passages, as they can be quickly opened for friendly troops.
The lances may be of iron instead of wood and rectangular instead of
round; the axial beam may be solid or composite. Figs. 8 and 9 show
methods of constructing cheveaux de frise with dimension stuff.

[Illustration: Fig. 6]

[Illustration: Fig. 7]

[Illustration: Fig. 8]

[Illustration: Fig. 9]

=1180. A formidable obstacle against cavalry= consists of railroad
ties planted at intervals of 10 feet with the tops 4-1/2 feet above
the ground, and connected by a line of rails spiked securely to each,
Fig. 7. The rail ends should be connected by fish plates and bolted,
with the ends of the bolts riveted down on the ends.

Figs. 10 and 11 show forms of heavy obstacles employed in Manchuria by
the Russians and Japanese, respectively. The former is composed of
timber trestles, made in rear and carried out