High Entanglements are strung on metal or wood posts about four feet high, both wire and posts being painted for camouflage. The driving of posts must be muffled, and metal screw posts are used when near the enemy's line. Posts are placed in two parallel lines, two yards apart, spaced alternately so that the posts in one line are opposite the middle of the interval in the other. Tracing Entanglements is done by a sergeant followed by two stake placers, two holders and two drivers, who in turn are followed by men attaching wire. Two men carry each roll of wire, and each pair (there are twelve pairs in all) strings one wire. A panel between stakes is composed of four strands. Each wire should be wrapped around each post. The same arrangement of panels should run between the two lines of posts. The entanglements are in three lines about 20 yards apart, the nearest being 20 yards from the front line trench. The entanglement nearest the enemy should be constructed first, so that men always work nearest their own trenches. All wire entanglements should be at all points commanded by the flanking fire of machine guns. High entanglements (known as abatis) may be made by felling trees toward the enemy, and similar entanglements made of brushwood are useful in emergency. Low Entanglements are formed of pickets two feet high, 2-1/2 inches in diameter, wired in all directions. Vegetation renders the entanglement invisible from the enemy and from aerial observation. This type may also be placed in shallow excavations which are concealed from the enemy and partly protected from artillery fire. Sharpened stakes, with their points hardened by fire, driven obliquely into the ground, may also be used. Loose Wire in the form of loops of small diameter fastened to stakes, or wire laid along the ground and attached at the ends, or spirals of barbed wire in racks, is used for entanglements. It is reported that this form is coming into considerable use, but the details have not been published. Such entanglements are much harder to locate by aerial observation. * * * * * The following are a number of criticisms made by Lieut. Henri Poire of the French army, detailed as instructor at Plattsburg, upon the system of field works constructed by the 17th and 18th Provisional Training Regiments. The ground was of loose sand, with some gravel at a depth of about six feet. 1. Dimensions of trenches as laid out were not followed. (a) Bottom of trenches behind firing steps too narrow. (b) Firing step too deep. It should never be more than 3 feet 4 inches below berm of parapet. (c) Parapet much too thin in most cases. It should be at least three feet thick. (d) Communication trenches (boyaux) generally too narrow. (e) Islands in communication trenches should never be less than 10 x 12 yards--otherwise one shell will demolish the entire passageway.