3. The use of visual signaling by means of lamps, fireworks and panels. Panels are pieces of cloth or other materials of various designs which are spread out on the ground in a manner to be easily seen by the airplane. They are for three purposes. 1. To signal to an airplane the identity and location of a unit’s headquarters by the use of its distinctive panel, called its “identification panel.” This is displayed either when the airplane requests it (by means of radio) or when the headquarters desires to attract the attention of the airplane. 2. To signal to the airplane other brief information by the use of rectangular panels known as “signaling panels” and arranged in various ways, either by themselves or in conjunction with the unit’s identification panel. 3. To signal to the airplane the position of the front line in a daylight advance by the use of special panels called “marking panels.” These are displayed only when called for by the airplane. All panels are removed as soon as an acknowledgment is received from the airplane. As the use of panels is always in conjunction with airplanes, all panel signallers should understand some of the uses of the various airplanes. Miscellaneous Methods of Visual Signaling. =Wig-Wag Flags.=—Flags for use in wig-wagging are now issued to divisions under the name of “kits, flag, combination, standard.” Each kit includes one wig-wag staff and two wig-wag flags, and also two semaphore staff and two semaphore flags. A division is supplied with 1,022 of these kits. The use of the wig-wag flags is already fairly well known in the American Army. Signals are transmitted by describing an arc of 90 degrees to the right and left to form dots and dashes, and spaces by a downward front motion. The general service can be transmitted by this means. Wig-wag flag signaling should be thoroughly understood and practiced by all signal men, as it forms an excellent method for becoming familiar with the code. Signals can be sent by this means merely by the use of the hand, and consequently the system forms an excellent way for troops to put in their time when traveling by train or on shipboard. Its use in the present war has been limited, but it will undoubtedly be used more and more, especially when open warfare is resumed. =Semaphore.=—Signals by semaphore are transmitted by the arms, either alone or with the semaphore flags that are issued in the standard combination flag kits. It is a standard means of communication in the American Navy and well known in the army. It is not used by the armies of Europe, but it might serve a useful purpose to linemen and others for intercommunication. Radio Equipment.