Ammunition boxes must be kept closed. Vickers belts should be kept in their boxes until actually required for use. The wooden belt boxes are fairly gas-tight, but the metal belt boxes should be made gas-tight by inserting strips of flannelette in the joint between the lid and the box.
Lewis magazines should be kept in some form of box, the joints of which are made as gas-tight as possible with flannelette.
A recess should be made, high up in the parapet if possible, for storing ammunition and guns. A blanket curtain, moistened with water or sprayer solution, will greatly assist in keeping the gas out.
(2) Hand And Rifle Grenades:
Unboxed grenades should be kept covered as far as possible. All safety pins and working parts, especially those made of brass, should be kept oiled to prevent their setting from corrosion by the gas.
(3) Light Trench Mortars And Their Ammunition:
As far as the supply of oil permits, the bore and all bright parts of light trench mortars and their spare parts should be kept permanently oiled. When not in use, mortars should be covered with sacking or similar material.
Unboxed ammunition should be kept covered as far as possible and the bright parts oiled immediately after arrival. Ammunition which has been in store for some time should be used up first.
Sentries must be prepared to give the alarm on the first appearance of gas, as a few seconds delay may involve very serious consequences. Signals must be passed along by all sentries as soon as heard.
The earliest warning of a gas attack is given: