The Ardois system of signaling 42 Sound signals 44 Improvised signal methods 44 CHAPTER III.--_Alphabets or systems of signals._ Signal alphabets: American Morse 45 Continental Morse 45 Army and navy 45 Abbreviations 46 Code calls 47 Execution of signal alphabets 47 The army and navy alphabet 47 The Morse alphabets 49 International code of signals: Description 51 Two-arm semaphore 51 The Ardois system 52 Coston signals 54 Very's night signals 54 Rocket signaling 55 Two-arm semaphore alphabet, U. S. Navy 57 Summary of signals, army and navy alphabet 60 CHAPTER IV.--_The field message._ Definition 64 The blank form 64 Writing the message 66 Instructions to operators: Use of message blank 66 Duties of sending operators 66 Order of transmission 66 Duties of receiving operators 67 Communications confidential 67 Checking the message 67