f gabions of other material than brush have been used.
Sheet iron and iron and paper hoops are some of them. The iron
splinters badly, is heavy, and has not given satisfaction. If any
special materials are supplied the method of using them will, in view
of the foregoing explanation, be obvious.

=1124. Timber or pole revetment.=--Poles too large for use in any
other way may be cut to length and stood on end to form a revetment.
The lower ends should be in a small trench and have a waling piece in
front of them. There must also be a waling piece or cap at or near the
top, anchored back. Fig. 21 shows this form.

=1125. Miscellaneous revetments.=--Any receptacles for earth which
will make a stable, compact pile, as =boxes=, =baskets=, =oil or other
cans=, may be used for a revetment. =Barrels= may be used for gabions.
=Canvas= stretched behind pickets is well thought of in a foreign
service. If the soil will make =adobe=, or sun-dried bricks, an
excellent revetment may be made of them, but it will not stand wet
weather.

Knots

=1126.= =Square= or =reef knot=, Fig. 22, commonly used for joining
two ropes of the same size. The standing and running parts of each
rope must pass through the loop of the other in the same direction, i.
e., from above down ward or vice versa; otherwise a _granny_, is made,
which is a useless knot that will not hold. The reef knot can be upset
by taking one end of the rope and its standing part and pulling them
in opposite directions. With dry rope a reef knot is as strong as the
rope; with wet rope it slips before the rope breaks, while a double
sheet bend is found to hold.

[Illustration: Fig. 22

_Square or Reef_]

=1127. Two half hitches=, Fig. 23, especially useful for belaying, or
making fast the end of a rope round its own standing part. The end may
be lashed down or seized to the standing part with a piece of spun
yarn; this adds to its security and prevents slipping.

This knot should never be used for hoisting a spar.

[Illustration: Fig. 23

_Two half hitches_]

=1128. Clove hitch=, Fig. 24, generally used for fastening a rope at
right angles to a spar or at the commencement of a lashing. If the end
of the spar is free, the hitch is made by first forming two loops, as
in Fig. 26, placing the right-hand loop over the other one and
slipping the double loop (Fig. 27) over the end of the spar. If this
can not be done, pass the end of the rope round the spar, bring it up
t