=Adjustments of Lamps.=—The reflecting apparatus of a lamp is carefully adjusted before it is issued. However, it is possible that a slightly different adjustment will give better results when a new bulb is inserted. To focus the lamp the light is flashed on some dark background, such as wall a few yards away, and the screws supporting the parabolic mirror carefully turned until the light becomes concentrated in the smallest possible circle. The adjustment screws are then tightened, but they should never be set tight. If the receiving operator is having trouble in receiving signals, he will inform the sending station by sending a series of dots. The sending operator will then examine his apparatus to see if the lamp is properly directed at the receiving station, if the reflector is out of focus, or if the battery has become weak. The receiving operator indicates the manner in which he is receiving the signals by the method in which he sends the dots. If the signals become worse, the dots are made more rapidly. As the adjustment becomes better, the dots are made more slowly. When a good readable adjustment has been obtained, he will signal BR, meaning “go ahead.” PRECAUTIONS IN LAMP SIGNALING. Don’t leave the lamp cover open when not in use. Don’t forget to open it when you start to transmit. Don’t touch the mirror. If necessary, it should be cleaned by wiping with gauze or cotton or wiped with clean water. Don’t pull the wire cable fastened to the bottom of the lamp when removing from the box. Don’t return broken or burned-out globes to the pouch, but throw them away unless ordered to turn them in. Don’t use the lamp for illuminating purposes. Don’t neglect to keep a constant watch on the stations with which you are supposed to communicate. SIGNALING RANGE OF LAMPS. Day. Night. 14 cm 1 to 3 kilometers 2 to 6 kilometers. 24 cm 1 to 6 kilometers 3 to 10 kilometers. 35 cm 5 to 10 kilometers 8 to 15 kilometers. Signals may be transmitted by using either white or red bulbs, but the range when using red bulbs is reduced approximately 50%. GENERAL SERVICE CODE AND CONVENTIONAL SIGNALS FOR USE WITH PROJECTORS, BUZZERS AND WIGWAG. A .- G --. M -- S ... Y -.-- 5 ..... B -... H .... N -. T - Z --.. 6 -.... C -.-. I .. O --- U ..- 1 .--- 7 --... D -.. J .--- P .--. V ...- 2 ..--- 8 ---.. E . K -.- Q —.- W .—. 3 ...— 9 ----. F ..-. L .-.. R .-. X -..- 4 ....- 10 ----- Manner of Sending Messages.