Definition.—The term "field message" is applied to all messages sent over field lines of information. All field messages for transmission over field lines of information by electrical or visual means should be plainly written by the sender on the blank forms in the United States Army Field Message Book. The practice of verbally delivering telegrams to enlisted men for transmission should invariably be discouraged.

"In framing telegrams, all words not important to the sense will be omitted. The last name of the officer addressed, or his title, and the last name of the sender are generally sufficient." (Paragraph 1198, Army Regulations.)

The blank form.—The United States Army Field Message Book issued by the Signal Corps is 4⁵/₈ inches wide by 6¾ inches long, and contains 40 message blanks with duplicate tissue sheets and two sheets of carbon paper.

The message is written on the yellow sheet, which can be torn out for delivery. The carbon sheet is attached to the book, and contrary to the custom in most carbon duplicating books, is placed under the tissue sheet when a message is being written. When not being used, the carbon sheet should invariably be kept in the back of the book. When the upper carbon sheet has become worn out, it should be torn out and the second carbon sheet used instead. The blank form is shown in figure 16. The back of the blank is ruled in squares and provided with scales for use in making sketches.

Writing the message.—In writing the message the name of the sending detachment should appear after the heading "from" on the upper line, as "from Headquarters 1st Brigade," while the location of the sender should appear on the second line after the heading "at." The heading "hour" on the third line should show the hour the message was written and not the hour the message was transmitted. The heading "received" at the bottom of the page is filled in by the addressee and shows the time of the receipt of the message by him.

INSTRUCTIONS TO OPERATORS.

Use of message blank.—The field message blank will be used for field messages both sent and received.

Duties of sending operators.—The sending operator will enter the time when the message is handed him for transmission in the left-hand corner at the bottom of the blank opposite the word "Received." He will enter in the proper places, at the head of the blank, the number of the message, the call letter of his station, with his personal signal, the check (number of words or groups of cipher contained in message, counting address and signature), and, after "OK" has been received, he will enter the time the message was sent, and the call letter of the receiving station, with the personal signal of the receiving operator.

Order of transmission.—To transmit a message, the operator will send: (1) The number of message and call letter of his station; (2) his personal signal; (3) the check; (4) "fm" followed by name of sending detachment; (5) "at" followed by location of sending detachment and date; (6) "Ho" followed by hour (a. m. or p. m.) message was written; (7) address in full; (8) period, (--——--); (9) body of message; (10) "sig" (signature follows); (11) signature.

Duties of receiving operators.—The receiving operator will add to the message received, the month, date, and year, and omit the "sig," "fm," and "at," and, after satisfying himself that the check and number of words correspond will give "OK" followed by the call letter of his station and his own personal signal. He will then enter in the proper places, at the head of the blank, the call letter of his own station, with his personal signal and the time the message was received.

Communications confidential.—Communications transmitted by telegraph or signals are always confidential and will only be revealed to those officially entitled to receive them.

Checking the message.—In preparing the "check" of the message, all words and figures written in the address, body of the message, and the signature will be counted.

In counting the check of a message, all words, whether in plain English, code, or cipher, pronounceable or unpronounceable, or initial letters, will be counted each as one word. The abbreviations for the names of places, cities, towns, villages, States, Territories, and Provinces, will be counted as if written in full. In the names of towns, counties, countries, or States, all of the words will be counted.

Abbreviations of weights and measures in common use, and cardinal points of the compass, will be counted each as one word.

To prevent liability to error, numbers and amounts should be written in words, and when not so written, the receiving operator will request that it be done. If the writer declines to write the amounts in words, the message will be accepted as written, and each figure will be counted as one word.

Figures, decimal points, and bars of division, and letters will be counted each separately as one word.

In ordinal numbers, the affixes, st, d, nd, rd, and th, will each be counted as one word.

In transmitting the telegram shown in figure 16, the following would be sent by the operator: