ne guns must be cleaned after a gas attack and then
re-oiled. Oil cleaning will prevent corrosion for 12 hours or more,
but the first available opportunity must be taken to dismantle machine
guns and clean all parts in boiling water containing a little soda. If
this is not done, corrosion continues slowly even after oil cleaning
and may ultimately put the gun out of action.

After a gas attack, S.A.A. should be carefully examined. All rounds
affected by gas must be replaced by new cartridges immediately and the
old ones cleaned and expended as soon as possible.

All hand and rifle grenades exposed to the gas should have their
safety-pins and working parts cleaned and re-oiled.

All bright parts of light trench mortars, together with all
accessories and spare parts exposed to the gas, must be cleaned and
wiped dry as soon as possible after the attack and in any case within
24 hours, after which they should be thoroughly coated afresh with
oil. The same applies to ammunition which may have been exposed to the
gas.

Ammunition which, for any reason, had not been oiled, must be cleaned
and oiled and expended as soon as possible.

For details regarding the cleaning of guns and artillery ammunition
and signal equipment, see paragraphs 116 and 123.

6. TREATMENT OF SHELL HOLES:

In the neighborhood of shelters or battery positions where gas from
shell holes is causing annoyance, the holes and the ground round them
should be covered with at least a foot of fresh earth. Shell holes so
treated should not be disturbed, as the chemical is not thereby
destroyed and only disappears slowly.

Concealment From Aerial Observers.

A. 1. An aeroplane cannot conduct reconnaissance at a height of less
than 5,000 feet without being within easy range of
anti-aircraft artillery; nor of less than 2,000 feet without
coming into range of machine-gun and rifle fire.
2. To be observed from such heights, objects on the ground must be
distinguished by:
(a) Motion.
(b) Color contrast.
(c) Line contrast, or
(d) Shadows.

B. Concealment:
1. (a) On warning of hostile aircraft, troops on the march should
withdraw to the side of the road (if possible, into shade),
or lie down flat in the road and remain motionless.
(b) If it is necessary to continue the march, this should be
done in broken detachments, which are far less distinct