VISUAL SIGNAL APPARATUS. The Signal Corps of the United States Army employe, two standard signal flags, 4 and 2 feet square respectively, with white ground and red centre, or the re verse. They are attached to light jointed rods and swung to the right, left, and centre when signaling. Any other flag, a piece of cloth, hand kerchief, or other object attached to a stick may he used in the same way.
The accompanying diagram shows the method of signaling with the flag, which is virtually the same with torch, hand-lantern, or beam of the search light with such modifications as are neces sary with these particular instruments. There is one position and three motions. The signal man stands in the first position holding his flag as shown in Fig. 1, facing squarely toward the station with which lie desires to communicate. The first motion, corresponding to signal 'one' or 1, is to the right of the centre, the flag describing the motion as shown in Fig. 2. The second mo tion, corresponding to 'two' or 2, is to the left and is shown in Fig. 3. The third motion is down ward directly in front of the signalman and then returned upward to the first position, and is `three' or 3. A combination of movements is shown in Fig. 4 and Fig. 5, Fig. 4 showing the signals corresponding to 12, while Fig. 5 shows
the signals corresponding to 2121. If 12 is sent repeatedly it means that it is desired to stop the signals from the sending station.
For night signaling the signal torch is em ployed. It consists of a cylinder of copper closed at one end, filled with a combustible material and lighted. Cotton strands saturated with turpen tine or' kerosene are generally used. The flying shutter or screen, and a mirror bar. The 'station kit' for permanent or semi-permanent stations uses 8-inch mirrors with provision for attach torch is attached to a staff and used like the flag. The foot torch is placed on the ground in front of the operator and used as a point of reference. In their place may be used ordinary hand lanterns, the usual arrangement being one strapped on the waist and one in each hand for homographic signals.
Signal flush lanterns using oil are also em ployed, and are attached to a tripod, the occult ing shutters being placed on another as with the heliograph (see illustration below), while an acetylene flash lamp which occults by shutting off the gas with a key similar to the ordinary telegraph key is another device for this purpose.