CORRUGATED IRON. Generally, when lengths of corrugated iron and plenty of floor boards and stakes are available, this material is used for revetting the lower half of a trench wall, as it removes a great many difficulties, such as looking over substantial foundations for sandbag revetments. It makes it unnecessary to fill sandbags, etc., thus saving a great amount of time and labor. In revetting with corrugated iron and stakes or hurdles, cut the slope or wall from 10 to 15 degrees from the perpendicular, putting the soil in the sandbags and leaving it in some handy place for any future use. Then, drive 6´ to 8´ stakes well into the trench foundation and approximately 4´ apart, thus giving adequate protection to each piece of corrugated, having the stakes at an angle of 15 degrees at least, from the perpendicular, and 6″ or 8″ away from the trench wall. Then, slide the corrugated, hurdles, or boards on their sides down behind the stakes, overlapping slightly the ends and ramming them well down into the mud or soil in the bottom, and filling in the space behind with soil. The bottom third or half of the front wall is thus substantially, easily and quickly revetted, and the upper half or remainder is generally revetted with the sandbags, a bed being dug so that the first layer of headers is about half its depth below the top of the corrugated. If stakes shorter than 6´ or 8´ have been used in the revetting, half should be cut off to where the sandbag revetting commences and wired to anchor stakes, driven into the parapet end of the bed, and not wired over the top of the parapet, as it tends to gradually pull them upwards. Then cover this wiring with your first layer of headers. When hurdles or floorboards are used instead of corrugated iron, empty sandbags or similar material must be hung behind them to prevent the soil crumbling through and thus weakening the foundation of the sandbag revetments. Corrugated should not be used for revetting the front wall higher than 2´, which is the width of one sheet, as the supply is generally limited and can be put to more valuable use as dealt with later. Corrugated iron comes in bundles of about 24 sheets to the bundle, averaging 6´ by 3´. Two sheets is the average load for any one man in a carrying party. A front wall constructed in the manner shown, if prompt and immediate attention always be given to repair if damage is done, will give very little bother. It is the usual custom to construct your fire platform after this revetting work has been done.