=172.= When calling for any purpose, challenging, or holding communication with any person a dismounted sentinel armed with a rifle or saber will take the position of port arms or saber. At night a dismounted sentinel armed with a pistol takes the position of raised pistol in challenging or holding communication. A mounted sentinel does not ordinarily draw his weapon in the daytime when challenging or holding conversation; but if drawn he holds it at advance rifle, raise pistol, or port saber, according as he is armed with a rifle, pistol, or saber. At night in challenging and holding conversation his weapon is drawn and held as just prescribed, depending on whether he is armed with a rifle, pistol, or saber. No. 8: =In case of fire or disorder to give the alarm.= =173.= In case of fire, a sentinel will call, "=Fire, No. (----)=," adding the number of his post; if possible, he will extinguish the fire himself. In case of disorder he will call, "=The Guard, No. (----)=," adding the number of his post. If the danger be great, he will in either case discharge his piece before calling. No. 11: =To salute all officers and all colors and standards not cased.= =174.= When not engaged in the performance of a specific duty, the proper execution of which would prevent it, a member of the guard will salute all officers who pass him. This rule applies at all hours of the day or night, except in the case of mounted sentinels armed with a rifle or pistol, or dismounted sentinels armed with a pistol, after challenging. (See par. 181.) =175.= Sentinels will salute as follows: A dismounted sentinel armed with a rifle or saber salutes by presenting arms; if otherwise armed, he salutes with the right hand. A mounted sentinel, if armed with a saber and the saber be drawn, salutes by presenting saber; otherwise he salutes in all cases with the right hand. =176.= To salute, a dismounted sentinel, with piece at a right shoulder or saber at a carry, halts and faces toward the person to be saluted when the latter arrives within 30 paces. The limit within which individuals and insignia of rank can be readily recognized is assumed to be about 30 paces, and therefore at this distance cognizance is taken of the person or party to be saluted. =177.= The salute is rendered at six paces; if the person to be saluted does not arrive within that distance, then when he is nearest. =178.= A sentinel in a sentry box, armed with a rifle, stands at attention in the doorway on the approach of a person or party entitled to salute, and salutes by presenting arms according to the foregoing rules. If armed with a saber, he stands at a carry and salutes as before. =179.= A mounted sentinel on a regular post, halts, faces, and salutes in accordance with the foregoing rules. If doing patrol duty, he salutes, but does not halt unless spoken to.