The navy semaphore consists of four arms pivoted at the ends, three on one side of the upright, or pole, and one on the other side. These arms have three positions: Horizontal; upward at an angle of 45° to the horizontal; downward at an angle of 45° to the horizontal.
Full instructions for the operation of the semaphore, and also for the use of balls, cones, drums, pennants, and whefts as distant signals, are given in the International Code of Signals.
THE SEARCHLIGHT.
The electric searchlight, when available, can often be successfully employed for night signaling, frequently affording efficient means of communication between ships and shore stations, when wireless working is impracticable. This system of visual signaling is practicable and especially valuable where the stations are, on account of the terrain, not intervisible.
Methods of employment.—In signaling with the searchlight the usual method of handling the shaft or beam is identical with that employed with the flag. In the first position the beam is shown vertically, while motions to the right, the left, and directly serve to indicate the elements of the alphabet. Chronosemic signals may also be used in searchlight signaling, the shaft of light being directed intermittently on some conspicuous object, such as a cloud, balloon, or high mountain top.
COSTON SIGNALS.
These signals are pyrotechnic compositions which burn with great intensity of light and color. The colors red, white, and green are found best suited for signaling. The signals are prepared in the form of cartridges and are burned from a holder. The colors burned may indicate the elements of any alphabet, or such other special signals as may be desired.