M pendant, divided horizontally red, yellow, red
N pendant, divided horizontally yellow, blue, yellow
O flag, divided diagonally red & yellow = O " " "
S pendant, divided vertically blue & yellow
T pendant, blue with white ball = D " " "
U burgee, divided vertically white & blue = A " " "
X pendant, striped vertically black & yellow
Affirmative } Preparative } as in 1790 (see Plate XIII) Negative flag, white with 5 black crosses
1 as No. 5 in 1790 2 " 2 " 3 flag, chequered yellow & blue 4 as No. 9 in 1790 5 flag, divided horizontally red & white 6 as No. 8 in 1790 7 " " 8 flag divided vertically red, white, blue 9 as "Dissent" in 1790 0 as No. 0 in 1790
(3) A series of numbered and special pendants:--
1 divided vertically red, white, blue 2 " horizontally " " 3 white with red cross 4 striped vertically white & red (16 stripes)
6 white with 2 black crosses 7 divided quarterly white, black, yellow, red 8 red 9 white with red ball 0 divided vertically yellow & blue Interrogative divided quarterly red & white Answering " vertically " " Guard, red with white cross Numeral, chequered blue & yellow Church, as No. 2 but with St. George's Cross in chief.
These pendants are all of a different shape from those employed in the alphabetical series, being more narrow and elongated, and cut off square at the end, whereas the former are almost equilateral and might perhaps be more correctly designated as "triangular flags."
1st. (repeating the 1st. flag or pendant of a "series") the Affirmative flag 2nd. ( " 2nd. " " " ) Answering pendant 3rd. ( " 3rd. " " " ) No. 2 pendant 4th. ( " 4th. " " " ) No. 0 " 1st. (when using the numbered pendants) Interrogative pendant 2nd. ( " " " ) Answering "
With these we have probably reached the final development of form so far as flag signals are concerned, for wireless has taken the place of visual signalling to such an extent that it is not likely that circumstances can now arise that will necessitate any radical recasting of the flag signal system.
Some elementary flag signals, notably that for a pilot, were in use among merchantmen at least as early as the fifteenth century, but the first attempt to supply a code of signals suitable for merchant ships appears to have been that made by Sir Home Popham in 1804, when, at the request of the East India Company, he compiled a book of "Commercial and Military Signals" for the use of the ships in their service. In this book the "military" element preponderates, as might be expected from the circumstances of the time at which it was drawn up. The signals relate almost exclusively to the fighting and manoeuvring of ships sailing in convoy. After the peace, in 1817, Captain Frederick Marryat drew up what may be regarded as the precurser of modern commercial codes. It was in six parts, each in the simple numerary system, with a distinguishing flag to indicate the part to which the signal related. The parts were as follows: 1. Names of men-of-war. 2. Names of merchantmen. 3. Ports, headlands, etc. 4. Sentences on various subjects. 5 and 6. A vocabulary adapted from Popham. This signal book went through ten editions before the author's death in 1848.