infantry while it rallies. This obstacle was formerly a wet or dry
ditch, with escarp, counterscarp and flanking galleries; but with the
new design of parapet a simpler form of obstacle was adopted. This was
obtained by carrying down and forward the slope of the parapet to a
point well below the level of the surrounding ground, and then placing a
stout fence at the foot of the parapet and concealed from view. It is in
fact the old principle of the sunk fence, and has this further
advantage, that the fence, being visible from the parapet, can be kept
under fire by men posted between the guns without any special flanking
galleries.

Occasionally two or more batteries are placed inside one line of
obstacles, but usually each 2-gun battery is complete in itself.

Cases arise, e.g. with sites on the top of a cliff, where no obstacle is
required; in such places the parapet merges into the surrounding ground.

In old days the parapet was shaped with well-defined edges and slopes.
Now the parapet slopes gently down to the front and is rounded at the
sides, so as to present no definite edge or angle to the enemy, and
concealment is furthered by allowing grass or small scrub to grow over
the parapet and round the guns. In order to obtain complete concealment
from view the background behind the guns must be carefully studied from
the point of view of the attack. Sites on the sky-line, and marked
contrasts of colour or shape, should be avoided. In some cases extensive
planting, amounting to landscape gardening, is justified. This is most
easily arranged in the tropics, where plant growth is rapid. In all
cases the guns and their mountings should be coloured to blend with the
background and thus avoid hard lines and shadows.

Any change of principle such as that of 1885 involves improvements both
in guns and their adjuncts. Of these latter the most important was the
position-finder designed by Colonel Watkin. This instrument in its
simplest form, when the observer is following a ship through the
telescope of the instrument, draws on a chart the track of the ship, so
that the exact bearing and distance of the latter can be ascertained at
any time and communicated to the guns by electrical and other dials, &c.
The position-finder may be some distance from the guns it serves, and
connected with them by electric cable. The guns can then be placed well
under cover and in many cases out of sight of the target, giving a
measure of prote