Hearing masks, 43 Howitzers, 83 Hydroplanes, 48 Incendiary projectiles, 37 Infantry, 18, 112 Inspections, 24 Instruction, 122, 157 Italian airplanes, 37 Liquid fire, 11, 17, 153 Listening posts, 63, 70 Loopholes, 62 Machine-gun rifle, 117 Machine-gun shelters, 62, 86 Machine-guns, 35, 113, 115, 117 Map (directing), 42 Masks, 89, 151 Medical department, 20 “Minenwerfers,” 11, 68 Mines and counter-mines, 69 Monoplanes, 34 Morale of the French, 58 Motor cars, 73, 104 Motors, 39 Munition parks, 20, 100, 101 Munition supply, 105 Neutralization fire, 89, 91 Observation planes, 40 Observation posts, 62, 66 Offensive engagements and their preparation, 136 Officers (duties of), 123 Office staff, 25 Pack transport, 116 _Pare-éclats_, 60, 66 Periscopes, 66 Pershing, General, 58, 120 Photographs, aërial, 41 Planes for directing fire of artillery and movements of infantry, 20, 43 Planes for reconnoitring, 20, 40, 43 Plants of the Germans, 38, 39 Post of command, 23, 144 Powder, 102 Prolonged engagements, 143 Protecting line of the artillery, 65, 68 Railway troops, 70 Rear organization, 18 Re-entrants, 59 Regiment, 19 Relief maps, 42 Replacing guns, 107 Rest hospitals, 21 Retubing of guns, 108 Rifle, 112, 122 _Rigoles_, 61 Rockets, 43, 44, 146 Salients, 59 Shells, 150 mm., 54, 102 Shelters, 54, 65 Shock-troops, 129 Signalling, 146 Squadrillas, 35, 36 Staffs, 24 _Stations têtes d’étapes_, 101 Strategy, 11, 14, 15 Supply shelters, 104 Support trenches, 64, 84 Tactics, 10, 14, 15 Tanks, 84, 117 Tear-producing gas, 17, 152 Transportation by road, 73 Transportation of munitions by railroad, 100 Trench artillery, 83 Trench knives, 121 Trench of attack, 67 Trench organization, 51, 52, 58 Trucks, 105 Verdun, 12, 144 Winged torpedoes, 37 Wire entanglements, 63, 68, 86 Wireless, 43 Withdrawal of artillery, 97 Wounded, transportation of, 21 Yser front, 11 Zeppelins, 48, 93 _Zone d’étapes_, 101 Tactics and Duties for Trench Fighting By Georges Bertrand Capitaine, Chasseurs, de l’Armée de France and Oscar N. Solbert Major, Corps of Engineers, U.S.A. _16°. 35 Diagrams. $1.50 net. By mail, $1.65_ 000.7 (OD) 1st Ind. War Department, A. G. O., December 21, 1917--To Major O. N. Solbert, Corp of Engineers, Office of the Chief of Engineers. 1. The manuscript forwarded with this letter has been examined in the War College Division and the opinion given that it has exceptional merit, presenting the principles governing trench warfare in such a clear and logical manner that the publication, with some changes and additions,* will be of considerable value to our Officers.