THE FIRE SIGNALS OF POLYBIUS.
TNmodern war the Signal Servic) is equipped with all that
Science can provide, so that, at first sight, it would appear unlikely that any lessons of value could be learned from the writings of Polybius by an up-to-date " flag-walloper." But a close study of the description which he gives of contemporary methods of signalling reveals much to instruct the reader; indeed, it brings out the most interesting fact that the proficiency, in fire-signalling which was within the reach of a good army in the days of Hannibal is equal to anything we find in the history of our Army and Navy down till the last generation. Polybiui wrote after the fall of Carthage in 146 B.e., and had visited the scenes of many a cam- paign. He went through France, and may, indeed, have got as far as Great Britain. One would like to think that in his tour of Gaul he saw the " Imperial Troops " use their torch signals in hills and valleys where to-day the fine electric lamp of the British soldier flashes back its messages of progress.
Polybius describes first a system of signalling which was previously recorded by Aeneas Tacitus, about 300 B.C. The stations between which signals were to be exchanged were furnished with earthenware vessels "equal in all respects." These were fitted. with corks of somewhat shorter diameter than the vessels, while the corks were pierced with rods divided into equal portions " each of three fingers' breadth." These portions were marked with the main items of war news likely to require the immediate attention given to urgent signals, such as the fact that the- enemy cavalry were coming, or his infantry were on the move. The messages assigned to the portions could, of course, vary with the tactical situation, or at the discretion of the Army commander, as the military manuals might say. The vessels were fitted with taps to give an equal outflow. When the taps were turned on, the cork platforms would sink. simultaneously, and these signal tubs were carefully tested to prove this equality. Let us suppose two signal stations duly equipped with their signal tubs. If one of these wished to com- municate with the other, it would raise a torch, an action which the Army signaller of to-day describes as the Preparative. The receiving-station raises a torch in answer, and this is the signal for both stations to turn on the tap. The sending-station would note when the necessary section of rod sinks opposite the rim of the vessel and would immediately raise its torch. The receiving- station acknowledges in- kind, turns off the tap, and records- the message.
With a -few alterations, this system would have many advantages- to justify its use in a big field day across the water. When a trench system is stormed, communication with the rear is most difficult. Wires are laid only to be blown to hits ; runners fall, while visual signalling with helio, flag, lamp, or disc is at a severe discount, although occasionally used with success. Now, if an attacking battalion had a carefully graduated tube on the aide of which were written the few messages that matter—" Held up by obstacles," " Held up by machine guns," " Enemy counter-attack- ing," "Lengthen fuses"—and if the Brigade had a similar tube, the signalling would be easy. A prearranged rocket signal goes up from the signal station at Battalion Headquarters. The Brigade sends up another, and, as its stars burst, high above the smoke of battle, the little tape are turned on. At the moment—for the message must take no more than a certain number of seconds—when the water is level with the message required, the Battalion sends up a quick flare. The Brigade immediately stops the flow of water and notes the message : " We have got through " The prosaic mind will suggest that one might as well note the time on a watch with a second-hand, but the graduated tube would ensure that no mistakes would be made in identifying the message sent. And thus the peculiar nature of trench warfare Justifies a system which Polybius is compelled to despise. Polybius perceived that where only particular messages could be sent, there was a sad lack of flexibility, as it is clearly imperative that signals should " indicate whatever is needed." " For," he asks, and the question will arouse our sympathy, " how can the party to be relieved feel confidence if it does not know how many ships or how much corn have been despatched by the allies ? " Polybius, having decided that a signal system must be able to transmit any message, invented the following device to secure this. Each letter can be signalled separately, as in Morse, but the system of Polybius. is much simpler. The alphabet is divided into five groups, all of which have five letters except the fifth, which has only four. The following table shows the division :- 1 2 3 4 5 Tablets-left.
1 a f X
2
3 7 8 v o 4 8 t r 4 .1 5 E K 0 The signal stations have five tablets on which the groups, written vertically, are inscribed. To signal a message, the Preparative is to raise two torches. The receiving-station does likewise, and the message begins. A torch raised on the left of the signal station indicates the tablet containing the letter ; a torch raised to the right indicates the letter in the tablet. To prevent confusion between right and left signals, the stations were provided with two- funnelled stcnoscopes. To signal K, for example, would require two signals to the left, as it is in No. 2 [vertical] tablet, and five signals to the right, as it is the fifth letter in the tablet. So, too, p would be four to the left, two to the right. Or, to put it in drill language : " Top row—left ; Side row—right." It appears that the signals to right and left were made by showing the exact number of torches required, although it is not unlikely that the same.result was attained by the movement of a single torch from behind cover, as if one were to make the letters G or A in semaphore. In any case, the system was assuredly fairly speedy. Perhaps, with a well-trained station under the control of a capable caller or reader, a message might take not more than twice the time that lamp messages take to-day.
We see, then, that the art of visual signalling had attained a fairly high level at this date, and, in contrast to this, it is worthy of note that our " dot and dash " system was not introduced to the Navy till 1867, before which date signalling at night or in fog was very restricted. Further, it was not till 1865 that the Army paid any serious attention to signalling, so that one may dare to claim that the soldiers of Hannibal or Scipio were not uninstructed in comparison with the modern signaller, and could, indeed, were they recalled to this plane, take an intelligent and critical interest in our visual methods of to-day. Polybius closes his brief description with a short note on the necessity of practice; and one would imagine that many a composer of Army manuals is similarly inspired. " The moral is not to give up any useful accomplishment on account of its apparent difficulty, but to persevere, till it becomes a matter of habit, which is the way mankind has obtained all good things." And Polybius can claim with justice that the system invented by Cleoxenus and Democlitus, and perfected by himself, is no mean forerunner of the system now in use.
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