Page:The New International Encyclopædia 1st ed. v. 18.djvu/193

* SIGNALING AND TELEGRAPHING. 155 SIGNALING AND TELEGRAPHING. The accompanying diagram shows the method of signaling with the flag, which is virtually the same -with torch, hanj-luntcrn. or beam of the search light with such moiUhcalions 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 Hag as shown in Fig. 1, facing squarely toward the station with winch he desires to eonununieatc. 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 tile 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-perninnent stations uses 8-inch mirrors with provision for attach- A B NIGHT SIGNALING. A, with torch ; B, with lantern. 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 flash 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 occulta by shutting off the gas with a key similar to the ordinary telegraph key is another device for this purpose. The Heliogeaph (svn-u^iter) is an instru- ment designed for signaling by reflected sun flashes. The United States Army 'field kit' contains two 4-inch mirrors, two tripods, a Vol, xviii.— u HELlOGBAPn OP THE UNITED STATES ARMY SIGNAL COKP8. 1. Heliograph with two mirrors, sun in rear. 2. Helio- graph with one mirror and sighting rod. sun in front. 3. Screen mounted on tripod. A, tripod ; li, tripod bead ; (7, sun mirror ; D, station mirror ; E, mirror supports ; F, tan- gent screw for revolving mirror about horizontal axis: G, mirror bar; //.tangent screw witii ball-bearings for re- volving mirror about vertical axis: /. clamp screw lor attaching mirror bar to tripod ; A", spring for clamping mirrors and sighting rod; L, sighting rod with movable disit ; M, screen ; N, key for screen ; O, screen spring. ment to a post, stump, or other firm base instead of tripods. In setting up and adjusting the posi- tion of the sun is the guide for determining whether one or two mirrors should be used. When the sun is in front of the operator, that is, in front of a plane through his position, at right angles to the line joining the stations, the sun mirror only is required; with the sun in rear of this plane both mirrors should be used, although a single mirror may be used to advantage with the sun well back of the operator. In the former case the rays of the sun are reflected from the sun mirror di- rect to the distant station ; in the latter they are reflected from the sim mirror to the station mirror, thence to the distant observer. Under fa- vorable atmospheric conditions the range of the lieliograph is great. The greatest ranges (100 to 125 miles) ever attained with this instrument are credited to the United States Army during the course of experi- ments in April and May, 1*90, in Arizona and New Mexico, during which, by using intermediate stations, communication was maintained con- nectedly for about two weeks between points 2000 miles apart. Other signaling devices are used in addition to the standard apparatus above described as occasion justifies, among which are disks {single