Ascending galleries, 148 Armament, 100 Army of observation, 69 Artillery, first position, 75, 104 Artillery, first position opening fire, 67 Artillery, second position, 81 Artillery, second position opening fire, 83 Artillery-fire, opening, by defence, 104 Assault, 4 Assault, defence against, 7 Assault, dispositions for, 5 Assault of breach, 89 Attaching a miner, 177 Attack by mines, 169-171 Attack by sap, 91 Attack, close, 107 Attack, journal of, 97 Attack, plan of, 78 Attack, point of, 73 Attack, successive steps of, 64 Auger, earth, 138 Auxiliary frame, 144 B Battery, alternative construction, 50 Battery behind crest of hill, 53 Battery, breaching, 83 Battery, construction of, 48 Battery, constructing centre passage of, 48 Battery, counter, 82 Battery, definitions, 42 Battery, electric, 163-6 Battery, enfilading, 82 Battery, exposed sunken, 46 Battery for field-guns, construction of, 43 Battery for siege-guns and howitzers, 44 Battery for siege-guns, ammunition required, 44 Battery, general requirements of siege, 42 Battery, location of, 9, 75 Battery, mortar, 55 Battery of rifled mortars and howitzers, 83 Battery on sloping ground, 53 Battery, sunken, in a parallel, 51