=The Officer and N. C. O. of the Watch.= During this time, the officer and the N. C. O. of the watch constantly make their rounds to see if the watchers are performing their duty efficiently. Instantly the alarm is given, the first duty of the officer of the watch is to set off the rockets calling for the barrage. At the same time, the orderly that accompanies him runs to the command post of the captain where the barrage call is confirmed by telephone and by rocket. Rocket signals are repeated and relayed from the same area until the barrage is obtained. =Defenders of the First Line.= Immediately the call to arms is given, the troops of the first line spring out of their shelters and take their places at the parapet of the firing trench. If these parapets and fire trenches have been destroyed, the troops are not in immediate grave danger, because at this moment the enemy’s barrage on your first line has lifted and is progressing toward the second line. Besides this, the assaulting troops can not subject the defenders to fire during the advance. Also, the assaulting column is subjected to the defensive barrage and is more or less in confusion, due to this fire and having to cross the shell-torn area of “No Man’s Land.” Then, too, what is left of your barbed wire entanglements will hold up the enemy’s troops. In short, the advantage at this particular point lies entirely with the defenders if they can occupy the first line in time. Among all the weapons of defense, the most powerful is the machine gun. The successful repulse of the hostile attack depends to the greatest extent upon the ability to use machine guns after the attack is under way. The opportune fire of one machine gun on the flank of an assaulting column may disorganize it and drive back its troops. =The Captain.= As soon as the alarm is given or it is known that the enemy’s attack has started, the captain throws his reinforcing platoons into the first line. These troops, in going forward, employ the boyaux laid down in the plan of defense. The hand grenades that they carry are stored in their dugouts. The chiefs of the reinforcing platoons do not necessarily wait for this order of the captain, but act upon their own initiative in sending forward their units. If, however, the first line has already been taken, the reinforcing platoons automatically carry out the functions of a counterattack by leaving their boyaux and going over the top to retake the captured trench. This last movement of over the top by the counterattacking troops is facilitated by the fact that the hostile artillery barrage has by this time passed to the rear of the first line. The next duty of the captain is to report to his chief of battalion the alarm, which is done by means of a chain of runners, by signaling, or by use of carrier pigeons, because usually by this time the telephone system has broken down under the artillery bombardment. III. Fighting in the Interior of the Position