(xiii) Company gas N. C. O.'s will report to company headquarters in readiness to assist the company commander should a gas attack occur.
(xiv) Medical officers will be responsible that a proper proportion of the ammonia capsules issued to them are with stretcher bearers in the front line in readiness for their immediate use after a gas attack.
(xv) Company gas N. C. O.'s will inspect daily all antigas apparatus—Strombos horns, flapper fans, vacuum bulbs, and stores of combustibles for clearing dugouts. They will see that gas-proof dugouts are kept in good order and the curtains sprayed.
(xvi) An officer on duty will be detailed from each company in reserve, except resting battalions.
(xvii) Commanders of units in billets east of the line Poperinghe—Bailleul—Estaires will organize a system of giving the alarm and rousing the men in cellars or houses.
20. ACTION DURING ENEMY GAS ATTACK.—In the event of an enemy gas attack the following action will be taken:
(i) The alarm will at once be given by all means available; by telephone, gongs, Strombos horns, and, if necessary, by orderly, and in accordance with paras. (iv) and (v).
(ii) There should be as Little Movement and Talking as Possible. All ranks will at once adjust their small box respirators. In front lines, and wherever the tactical situation demands, they will stand to arms. In rear lines, where there are large gas-proof dugouts, there is no objection, provided the tactical situation allows it, to men, with the exception of sentries and officers and N. C. O.'s on duty, remaining in the gas-proof dugouts. In any case small box respirators will be adjusted immediately the alarm is given and before the men leave the dugout.
(iii) On the alarm being given, all bodies of troops or transport on the move will halt, and all working parties cease work until the gas cloud has passed.
(iv) Should the gas cloud be unaccompanied by an infantry attack, the message "Gas attack, trench ________________," but not the S. O. S. signal, will be sent.