gas or between
gas clouds; it may also be used alone to distract attention from a
real discharge of gas, to cover the advance of infantry, or merely as
a false gas attack.

(4) MINE AND EXPLOSION GASES:

The poisonous gases which occur in mines, and which are formed in
large quantities when high explosive goes off in an enclosed space,
_e.g._, from a direct hit in a shelter, or on the explosion of a
charge in a mine, are not protected against by the ordinary anti-gas
appliances. The chief of these gases is carbon monoxide. Protection
against such gases will not be considered in these notes.

Officers are held responsible that all the anti-gas appliances for
protecting their men are maintained in perfect condition, and that all
ranks under their command are thoroughly trained in the use of these
appliances and in all other measures which may affect their safety
against gas.

Summary of Protective Measures:

(a) Provision to each man of individual protective devices.
(b) Arrangement for the inspection of those appliances and training
in their use and instruction in all other measures of gas
defense.
(c) Provision of protected and gas-proof shelters.
(d) Weather observations to determine periods when the conditions
are favorable to a hostile gas attack.
(e) Arrangement of signals and messages; for immediate warning of a
gas attack.
(f) Provision of appliances for clearing gas from trenches and
shelters.

C. Protection of Shelters:

(1) METHODS OF PROTECTION:

Protection of dugouts, cellars, buildings, etc., is given if all
entrances are closed by well-fitting doors or by blankets sprayed with
hypo. solution. Practically no gas passes through a wet blanket, and
the protection depends on getting a good joint at the sides and bottom
of a doorway, so as to stop all draughts. This can be effected by
letting the blanket rest on battens, fixed with a slight slope,
against the door frame. The blanket should overlap the outer sides and
a fold should lie on the ground at the bottom. A pole is fastened to
the blanket, which allows the latter to be rolled up on the frame and
causes it to fall evenly.

Wherever possible, particularly where there is likely to be movement
in and out of the shelter, two blankets fitted in this way but sloping
in opposite directions should be provided. There should be an interval
of at least three feet between the two frames, and the la