h it, the commander on the spot will substitute another
for it and report the case at once to headquarters.

217. In addition to the countersign, use may be made of pre-concerted
signals, such as striking the rifle with the hand or striking the
hands together a certain number of times as agreed upon. Such
signals may be used only by guards that occupy exposed points.

They are used before the countersign is given and must not be
communicated to anyone not entitled to know the countersign.
Their use is intended to prevent the surprise of a sentinel.

In the daytime signals such as raising a cap or a handkerchief
in a prearranged manner may be used by sentinels to communicate
with the guard or with each other.

SECTION 12. GUARD PATROLS.

218. A guard patrol consists of one or more men detailed for the
performance of some special service connected with guard duty.

219. If the patrol be required to go beyond the chain of sentinels,
the officer or noncommissioned officer in charge will be furnished
with the countersign and the outposts and sentinels warned.

220. If challenged by a sentinel, the patrol is halted by its
commander, and the noncommissioned officer accompanying it advances
alone and gives the countersign.

SECTION 13. WATCHMEN.

221. Enlisted men may be detailed as watchmen or as overseers
over prisoners, and as such will receive their orders and perform
their duties as the commanding officer may direct.

SECTION 14. COMPLIMENTS FROM GUARDS.

222. The compliment from a guard consists in the guard turning
out and presenting arms. (See par. 50.) No compliments will be paid
between retreat and reveille except as provided in paragraphs 361
and 362, nor will any person other than those named in paragraph
224 receive the compliment.

223. Though a guard does not turn out between retreat and reveille
as a matter of compliment it may be turned out for inspection
at any time by a person entitled to inspect it.

224. Between reveille and retreat, the following persons are
entitled to the compliment: The President; sovereign or chief
magistrate of a foreign country and members of a royal-family;
Vice President: President and President pro tempore of the Senate;
American and foreign ambassadors; members of the Cabinet; Chief
Justice; Speaker of the House of Representatives; committees of
Congress officially visiting a military post; governors within
their respective States and Territories; governors