When the call of a station is acknowledged, both stations will adjust each on the flash of the other. When adjustments are satisfactory, the station called will acknowledge and cut off its flash, and the calling station will proceed with its message. INTERNATIONAL CODE OF SIGNALS. _Description._--By means of the International Code of Signals people of different nationalities may communicate with each other, although neither party has knowledge of any language save his own native language. The code is, as its name indicates, international, and every seagoing vessel of every nation is equipped with its flags. The Code of Signals contemplates the use of 26 flags (figs. 14 and 15); one for each letter of the alphabet and a code pennant. Complete instructions relative to the use of this code are contained in a book issued by the Hydrographic Office, Navy Department, and known as the "The International Code of Signals." In using this system the signals are displayed by hoisting combinations of two, three, or four flags. All possible combinations represent words, expressions, or phrases, which may be found in the "International Code of Signals," referred to above. _Two-arm semaphore._--This system is frequently used by the United States Navy, the following instructions covering the use of the system: 1. To communicate with a station: Face the station and wave the flags over the head to attract attention, making at frequent intervals the call letter of the station. When the station called is ready to receive the message, it answers by displaying its own call letter until the sender makes the "alphabetical" or "numeral," as the case may be. Then proceed with the message. At the end of each word bring the flags across the lower part of the body. 2. To call a ship: Hoist International Code letter J and make code letter of ship; then proceed as in article 1. 3. To make a general semaphore signal: Hoist cornet; all ships answer by answering pennant; then make signal. 4. At the end of the message extend the arms horizontally and wave the flags until the receiver answers in the same manner, showing that the message is understood. Should the receiver miss a word, he signifies the fact by waving the flag over his head. The sender will then cease signaling and wave his flags similarly to show that he understands. The receiver then makes "repeat last word," or whatever he wishes to say. Should the sender make a mistake, he will make the "error" signal until answered by the receiver with the same signal. He then proceeds with the message. THE ARDOIS SYSTEM.