TITLE XXIII.

SEA SIGNALS.

ARTICLE 525. A signal code to be devised by an international committee. 526. The use of the international signal code to be enjoined upon all ships, for all communications by signal, except such as may be of a confidential nature.

527. Apparatus and printed instructions required for the use of the international signal code, to be provided.

A signal code to be devised by an international committee.

525. Within one year after the adoption of this Code, there shall be appointed a joint commission of competent persons, to fix upon a common system of signals to be used for purposes of communication between vessels at sea; such commission to consist of three members from each nation.

The use of the international signal code to be enjoined upon all ships, for all communications by signal, except such as may be of a confidential nature.

526. The signal system, fixed upon as provided in the last article, shall be used in all sea-going ships, public or private, bearing the national character of any of the nations parties to this Code, for all signal communications, except those which it may be necessary, in the public interest, to transmit confidentially.

Apparatus and printed instructions required for the use of the international signal code, to be provided.

527. Every sea-going ship, public or private, bearing the national character of any of the nations parties to this Code, must, before going to sea, be furnished with

all the apparatus necessary to be used, in the employment of the international signal code, for communications at sea; and also with full and complete printed instructions for the use of the same.

All signal codes, whether for sea service or for land service, rest upon the same fundamental principles. A signal is a demonstration of some kind, having a conventional significancy, and designed to assist in conveying ideas from one person to another. Where distance intervenes between the persons communicating, the signals must be addressed to the eye or to the ear. In either case, a distinction may be made between signals which are momentary or evanescent, and such as may be made permanent for any length of time, at will.

To the class of evanescent signals belong most of those which depend on motion. Some such may be seen in common life, in universal use; as, for instance, beckoning with the hand, nodding or shaking the head, &c.: and, in systematic signal codes, the waving of flags, the flight of rockets, and the report of fire-arms, possess the same character. Permanent, or more properly, lasting signals are such as remain unchanged to perception during a sensible period of time, which may be protracted at the pleasure of the exhibitor. Examples of these are hoists of flags, or prolonged blasts of steam-whistles or fog-trumpets, or attitudes assumed by the person himself who gives the signal.

The simple motions, sounds or displays employed in signal codes, are called elementary signals. The number of these is, in the nature of things, limited. No code of any comprehensiveness could be formed consisting of uncombined elementary signals only. A few elements will, however, form a very large variety, when they are associated together in groups. Groups of this kind are called combination signals. Such groups may be constructed in several modes; as, first, by combination proper, where, from a given number of elements, say six, there are formed assemblages of a smaller number, as of threes, of which no two shall be alike in all their elements; secondly, by permutation, where the same combination is made to furnish as many signals as there are different orders of succession in which its elements can be disposed; and thirdly, by arrangement, in which a very small number of elements may be made to furnish a very large number of signals, by repeating one or more of the elements several times in the same signal, and differently disposing the elements among themselves. (Myer's Manual of Signals.)

It may be said, generally, that it is not desirable to employ a large number of elementary signals in a signal code; also, that the principle of arrangement applied to a few elements will furnish more satisfactory results than permutation and combination only, applied to a larger number.

Codes of signals may be formed to signify letters, in which case communications may be made in any form of words, as by telegraph; or to signify numbers, which may then be employed to designate messages previously prepared, and inserted in their order in a dictionary. The ad

vantage of the first system is, that it leaves communication entirely free; and that of the second, that it economizes time, by conveying many words through a single number. A complete system should embrace both methods; the second, for that numerous class of communications the necessity of which is of frequent recurrence; and the first, for communications the nature of which cannot be anticipated.

The dot and line telegraphic alphabet illustrates the advantages of limiting the number of elementary signals employed in any system. By the principle of arrangement, two characters, or, at most, three, (a long line, a short one, and a dot,) suffice, in that instance, for the construction of an entire alphabet of signals, perfectly distinct from each other, and easily fixed in the memory. This alphabet, in itself, would form an amply sufficient signal code to enable two vessels at sea to communicate with each other, by means of steam-whistles, or by the more or less prolonged exposure and concealment of any visible object.

There are already in use certain signal codes, which have obtained something approaching to an international character. One of these is "The Universal Code," of the late Capt. Marryatt, of the British Royal Navy; another, "The Code International," of Capt. Reynold, of Paris; and a third, "The Commercial Code," of the British Board of Trade. The first and second of these use signal numbers, as ciphers of signal communication; while the third, or Commercial Code, uses signal letters, permuted in sets of two, three, and four each for the same purpose (Myer's Manual of Signals, p. 51). The code itself consists of words and sentences, classified according to subjects. Signals are shown by the required hoist of flags, each flag being the recognized symbol of a particular letter. This method originated in 1856, and (as above stated) under the auspices of the British Board of Trade; since which time, it has been gradually introduced into the war and merchant marine of the principal maritime nations of Europe. As yet, however, it is but partially used in the naval or commercial marine of the United States, although, by a general order of the Navy Department, the code has been issued to all the vessels of the United States Navy, together with the necessary signal flags.

The system of signals which seems to possess the largest capabilities of usefulness is that which is known by the name of the "Chronosemic Method" of signalling, invented by Benjamin Franklin Greene, Chief Clerk of the Bureau of Navigation, of the Navy Department of the United States. This system consists in employing measured intervals of time as the significant symbols, and using audible or visible signals for the purpose only of marking the beginnings and endings of these intervals. Any convenient small interval of time-say one, or three, or five seconds -may be taken as the unit interval; then this interval doubled, tripled, quadrupled, and so on, will give the successive additional symbols necessary to form the code.

This system possesses several advantages. It permits the use of the largest variety of signal apparatus; since it is a matter of entire indifference by what means the beginning and ending of each interval is marked,

so that the indication is distinct. Thus, for visible signals, by day, the exhibition and concealment, or the simple waving, of a flag; or the substitution for the flag of any brilliant or conspicuous object; or even, at small distances, a gesture of the arm of the signal officer; or, by night, the flashing of gunpowder, the ascent of a rocket, or the display and eclipse of a signal lantern; and in time of fog, the firing of ship's guns, the blowing of a steam whistle, or the sounding of a trumpet or bugle, may be resorted to equally and interchangeably, as convenience may suggest. It admits, in the second place, of a very large extension of the circle of available signal distance beyond the practical limit which at present exists; making it possible, for instance, by means of rockets or guns, to convey messages between vessels separated by ten, fifteen, or even twenty or more miles. To these advantages it may be added, that the chronosemic method, from the simplicity of sign-making apparatus which it allows, involves a smaller necessary expenditure than any other; while, for fog-signals especially, it has been found greatly more effective than any plan heretofore devised.

For these reasons, it should seem to be desirable that, in any system of sea-signals designed for international use, the chronosemic method, if not adopted to the exclusion of every other, should have an important place. It is better, nevertheless, that the details of the system should be arranged by men of experience, whose practical acquaintance with the merits of different methods entitles them to speak upon the subject with authority, rather than that they should be fixed by arbitrary legislation. This consideration has suggested the provisions of the text above, which leave the precise form of the international signal code to be settled by a committee of experts.

The foregoing remarks apply to signal-systems designed for general or extended communication. Alarm-signals, of which the object is to prevent collisions, or to give warning of danger, may be much more simple; but in order that they may be in the highest degree effectual in securing the safety of vessels at sea, it is important that they should be everywhere the same. In the United States, the Board of Supervising Inspectors of Steamboats have adopted the following rules for fog-horn signals:

"Whenever there is a fog, whether by day or night, the fog signals described below shall be carried and used, and shall be sounded at least every two minutes, viz.: steamships, and all other steamers, coasting and river, under way, shall use a steam-whistle; sailing and all other craft propelled by sails, under way, shall use a fog-horn, or equivalent signal; sailing ships, and every other craft propelled by sails, upon the ocean or lakes, shall, when on her starboard tack, blow one blast of her fog-horn, and when on her port tack, she shall blow two blasts of her fog-horn, at all times, at intervals of not more than two minutes; when hove to, she shall blow a general alarm; when at anchor, she shall blow her fog-horn, as at other times, at intervals of not more than two minutes. It shall at all times be the duty of steamers to give to the sailing vessel, or other craft propelled by sails, every advantage, and keep out of her way.

Steamships and sailing vessels, when not under way, or which shall be anchored or moored in or near the channel or fairway, as aforesaid, and not in any port, shall sound the fog-horn, at intervals of not more than two minutes; and all steamers navigating in a fog or thick weather shall sound their steam whistle at intervals of not more than one minute. Sailing vessels shall at all times, on the approach of any steamer during the night time, show a lighted torch upon that point or quarter to which such steamer shall be approaching; and upon any craft navigating rivers without being in tow of a steamer, such as rafts, flat boats, wood boats, and other like craft, shall sound a fog-horn, at intervals of not more than two minutes; and all steamers navigating rivers in fog or thick weather, shall sound their steam-whistles, at intervals of not more than one minute."