The addition of a loophole of sandbags on the top for concealment
(called _head-cover_), gives increased protection, but at the cost of
greater prominence for the parapet (fig. 85). Overhead cover can only
be provided in fire trenches by giving the parapet still greater
height and it is not usually done. Portions of the trench not used for
firing can, however, be given splinter-proof protection by putting
over them branches or bundles, covered with a few inches of earth: or
by boards, or sheets of corrugated iron if they can be had. A better
plan when time permits is to provide cover trenches immediately behind
and communicating with the fire trench.
[Illustration: From _Mil. Engineering: Field Defences_, by permission
of the Controller H. M. Stationery Office.