(v) Detached parties of men moving within a mile of the front line will strictly observe the precautions laid down in (ii), (iii), and (iv). Commanding officers will be held responsible that this is done.
(vi) The duties of sentries are:
(a) To give warning;
(b) To adjust immediately the curtains of gas-proof dugouts.
(vii) All working parties east of the line Poperinghe—Bailleul—Estaires will have a sentry posted to give instant warning of a gas attack.
(viii) A sentry will be posted at each Strombos horn or similar alarm and instructed in its use.
(ix) A sentry will be posted at every tunnel dugout or other dugout holding more than 10 men.
(x) A sentry will be posted to each group of two or three small dugouts.
(xi) A sentry will be posted on each headquarters, signal office, and independent body of men east of the line Poperinghe—Bailleul—Estaires.
(xii) Men sleeping in rearward lines, works, or rest billets where they are allowed to take off their equipment will sleep with their small box respirators round their necks, and must know exactly where their P. H. helmet is to be found.