. When the flag is being lowered at retreat, a sentinel on
post and in view of the flag will face the flag, and, at the
first note of the Star Spangled Banner or to the color will come
to a present arms. At the sounding of the last note he will resume
walking his post.

No. 12: To be especially watchful at night and during the time
for challenging, to challenge all persons on or near my post,
and to allow no one to pass without proper authority.

186. During challenging hours, it a sentinel sees any person
or party on or near his post, he will advance rapidly along his
post toward such person or party and when within about 30 yards
will challenge sharply, "Halt, Who is there!" He will place himself
in the best possible position to receive or, if necessary, to
arrest the person or party.

187. In case a mounted party be challenged, the sentinel will
call, "Halt, Dismount. Who is there?"

188. The sentinel will permit only one of any party to approach
him for the purpose of giving the countersign (pars. 209 to 217),
or, if no countersign be used, of being duly recognized. When
this is done the whole party is advanced, i. e., allowed to pass.

189. In all cases the sentinel must satisfy himself beyond a
reasonable doubt that the parties are what they represent themselves
to be and have a right to pass. If he is not satisfied, he must cause
them to stand and call the corporal of the guard. So, likewise, if
he have no authority to pass persons with the countersign, or
when the party has not the countersign, or gives all incorrect
one.

190. A sentinel will not permit any person to approach so close
as to prevent the proper use of his own weapon before recognizing
the person or receiving the countersign.

191. When two or more persons approach in one party, the sentinel,
on receiving an answer that indicates that some one in the party
has the countersign, will say, "Advance one with the countersign,"
and, if the countersign is given correctly, will then say, "Advance
(so-and-so)," repeating the answer to his challenge. Thus it the
answer be "Relief (friend with the countersign, patrol, etc.),"
the sentinel will say, "Advance one with the countersign"; then
"Advance, relief (friends, patrol, etc.)."

192. If a person having the countersign approach alone, he advanced
to give the countersign. Thus if the answer be "Friend with the
countersign (or officer of the day, or etc.)." the sentinel will
say, "Advance, frie