in general, the mark or character of something absent or invisible. See CHARACTER.

Among physicians, the term sign denotes some appearance in the human body which serves to indicate or point out the condition of the patient with regard to health or disease.

in algebra. See ALGEBRA, Part I.

in astronomy, a constellation containing a 12th part of the zodiac. See ASTRONOMY, no 318.

NAVAL SIGNALS. When we read at our fireside the account of an engagement, or other interesting operation of an army, our attention is generally so much engaged by the results, that we give but little to the movements which led to them, and produced them, and we seldom form to ourselves any distinct notion of the conduct of the day. But a professional man, or one accustomed to reflection, and who is not satisfied with the mere indulgence of eager curiosity, follows every regiment in its movements, endeavours to see their connection, and the influence which they have had on the fate of the day, and even to form to himself a general notion of the whole scene of action at its different interesting periods. He looks with the eye of the general, and sees his orders succeed or fail.

But few trouble themselves farther about the narration. The movement is ordered; it is performed; and the fortune of the day is determined. Few think how all this is brought about; and when they are told that during the whole of the battle of Culler, Frederic the Great was in the upper room of a country inn, from whence he could view the whole field, while his aids de camp, on horseback, waited his orders in the yard below, they are struck with wonder, and can hardly conceive how it can be done; but, on reflection, they see the possibility of the thing. Their imagination accompanies the messenger from the inn yard to the scene of action; they hear the General's orders delivered, and they expect its execution.

But when we think for a moment on the situation of the commander of a fleet, confined on board one ship, and this ship as much, or more closely, engaged, than any other of the fleet; and when we reflect that there are no messengers ready to carry his orders to ships of the squadron at the distance of miles from him, and to deliver them with precision and distinctness, and that even if this were possible by sending small ships or boats, the vicissitudes of wind and weather may render the communication so tedious that the favourable moment may be irretrievably lost before the order can be conveyed.—When we think of all these circumstances, our thoughts are bewildered, and we are ready to imagine that a sea-battle is nothing but the unconnected struggle of individual ships; and that when the admiral has once "cried havoc, and let slip the dogs of war," he has done all that his situation empowers him to do, and he must leave the fate of the day to the bravery and skill of his captains and sailors.

Yet it is in this situation, apparently the most unsignallable, that the orders of the commander can be language conveyed, with a dispatch that is not attainable in the to the eye operations of a land army. The scene of action is unincumbered, so that the eye of the General can behold the whole without interruption. The movements which it is possible to execute are few, and they are precise. A few words are sufficient to order them, and then the mere fighting the ships must always be left to their respective commanders. This simplicity in the duty to be performed has enabled us to frame a language fully adequate to the business in hand, by which a correspondence can be kept up as far as the eye can see. This is the language of signals, a language by writing, addressed to the eye, and which he that runneth may read. As in common writing certain arbitrary marks are agreed on to express certain sounds used in speech, or rather, as in hieroglyphics certain arbitrary marks are agreed on to express certain thoughts, or the subjects of these thoughts; so here certain exhibitions are made, which are agreed on to express certain movements to be executed by the commander to whom they are addressed, and all are enjoined to keep their eyes fixed on the ship of the conductor of the fleet, that they may learn his will.

It is scarcely possible for any number of ships to act in concert, without some such mode of communication between the general and the commanders of private ships. We have no direct information of this circumstance in the naval tactics of the ancient nations, the Greeks and Romans; yet the necessity of the thing is so apparent, that we cannot suppose it to have been omitted by the most ingenious and the most cultivated people who have appeared on the great theatre of the world; and we are persuaded that Themistocles, Conon, and other renowned sea commanders of Athens, had signals by which they directed the movements of their fleets. We read, that when Aegeus sent his son Theseus to Crete, it was agreed on, that if the ship should bring the young prince back in safety, a white flag should be displayed. But those on board, in their joy for reviving their country after their perilous voyage, forgot to hoist the concerted signal. The anxious father was every day expecting the ship which should bring back his darling son, and had gone to the shore to look out for her. He saw her, but without the signal agreed on. On which the old man threw himself into the sea. We find, too, in the history of the Punic wars by Polybius, frequent allusions to such a mode of communication; and Ammianus Marcellinus speaks of the speculatores and vexillarii, who were on board the ships in the Adriatic. The coins both of Greece and Rome exhibit both flags and streamers. In short, we cannot doubt of the ancients having practised this hieroglyphical language. It is somewhat surprising that Lord Dudley, in his Arcano del Mare, in which he makes an ostentatious display of his knowledge of everything connected with the sea service, makes no express mention of this very essential piece of knowledge, although he must, by his long residence in Italy, have known the marine discipline of the Venetians and Genoese, the greatest maritime powers then in Europe.

In the naval occurrences of modern Europe, mention is frequently made of signals. Indeed, as we have already observed, it seems impossible for a number of ships to act in any kind of concert, without some method of communication. Numberless situations must occur, when it would be impossible to convey orders or information by messengers from one ship to another, and coast and alarm signals had long been practised by every nation. The idea was, therefore, familiar. We find, in particular, that Queen Elizabeth, on occasion of the expedition to Cadiz, ordered her secretaries to draw up instructions, which were to be communicated to the admiral, the general, and the five counsellors of war, and by them to be copied and transmitted to the several ships of the navy, not to be opened till they should arrive in a certain latitude. It was on this occasion, (says our historian Guthrie), "that we meet with the first regular sets of signals and orders to the commanders of the English fleet." But, till the movements of a fleet have attained some sort of uniformity, regulated and connected by some principles of propriety, and agreed on by persons in the habit of directing a number of ships, we may with confidence affirm that signals would be nothing but a parcel of arbitrary marks, appropriated to particular pieces of naval service, such as attacking the enemy, landing the soldiers, &c.; and that they would be considered merely as referring to the final result, but by no means pointing out the mode of execution, or directing the movements which were necessary for performing it.

It was James II. when duke of York, who first considered this practice as capable of being reduced in form into a system, and who saw the importance of such a system composition. He, as well as the king his brother, had always showed a great predilection for the sea service; and, when appointed admiral of England, he turned his whole attention to its improvement. He had studied the art of war under Turenne, not as a pastime, but as a science, and was a favourite pupil of that most accomplished general. Turenne one day pointed him out, saying, "Behold one who will be one of the first princes and greatest generals of Europe." When admiral of England, he endeavoured to introduce into the maritime service all those principles of concert and arrangement which made a number of individual regiments and squadrons compose a great army. When he commanded in the Dutch war, he found a fleet to be little better than a collection of ships, on board of each of which the commander and his ship's company did their best to annoy the enemy, but with very little dependence on each other, or on the orders of the General; and in the different actions which the English fleet had with the Dutch, every thing was confusion as soon as the battle began. It is remarkable that the famous pensionary De Witt, who from a statesman became a navigator and a great sea commander in a few weeks, made the same representation to the States General on his return from his first campaign.

In the memoirs of James II. written by himself, we have the following passage: "1665. On the 15th of March the duke of York went to Gunfleet, the general rendezvous of the fleet, and hastened their equipment. He ordered all the flag officers on board with him every morning, to agree on the order of battle and rank. In former battles, no order was kept, and this under the duke of York was the first in which fighting in a line and regular form of battle was observed."

This must be considered as full authority for giving the duke of York the honour of the invention. For whatever faults may be laid to the charge of this unfortunate prince, his word and honour stand unimpeached. And we are anxious to vindicate his claim to it, because our neighbours the French, as usual, would take the merit of this invention, and of the whole of naval tactics, to themselves. True it is, that Colbert, the great and justly celebrated minister of Louis XIV., created a navy for his ambitious and vain-glorious master, and gave it a constitution which may be a model for other nations to copy. By his encouragement, men of the greatest scientific eminence were engaged to contribute to its improvement; and they gave us the first treatises of naval evolutions. But it must ever be remembered, that our accomplished, though misguided sovereign, was then refiling... residing at the court of Louis; that he had formerly acted in concert with the French as a commander and flag officer, and was at this very time aiding them with his knowledge of sea affairs. In the memorable day at La Hogue, the gallant Ruffel, observing one of Fourville's movements, exclaimed, "There! they have got Pepys among them." This anecdote we give on the authority of a friend, who heard an old and respectable officer (Admiral Clinton) say, that he had it from a gentleman who was in the action, and heard the words spoken; and we trust that our readers will not be displeased at having this matter of general opinion established on some good grounds.

It was on this occasion, then, that the duke of York made the movements and evolutions of a fleet the object of his particular study, reduced them to a system, and compiled that "System of Sailing and Fighting Instructions," which has ever since been considered as the code of discipline for the British navy, and which has been adopted by our rivals and neighbours as the foundation of their naval tactics. It does great honour to its author, although its merit will not appear very eminent to a careless surveyor, on account of that very simplicity which constitutes its chief excellence. It is unquestionably the result of much sagacious reflection and painful combination of innumerable circumstances, all of which have their influence; and it is remarkable, that although succeeding commanders have improved the subject by several subordinate additions, no change has to this day been made in its general principles or maxims of evolution.

Till some such code be established, it is evident that signals can be nothing but arbitrary and unconnected hieroglyphics, to be learned by rote, and retained by memory, without any exercise of the judgment; and the acquisition of this branch of nautical skill must be a more irksome task than that of learning the Chinese writing. But such a code being once settled, the character in which it may be expressed becomes a matter of rational discussion.

Accordingly, the sailing and fighting instructions of the duke of York were accompanied by a set of signals for directing the chief or most frequent movements of the fleet. These also were contrived with so much judgment, and such attention to distinctness, simplicity, and propriety, that there has hardly been any change found necessary; and they are still retained in the British navy as the usual signals in all cases when we are not anxious to conceal our movements from an enemy.

Notwithstanding this acknowledged merit of the duke of York's signals, it must be admitted that great improvements have been made on this subject, considered as an art. The art military has, in the course of a century past, become almost an appropriate calling, and has therefore been made the peculiar study of its professors. Our rivals the French were sooner, and more formally, placed in this situation, and the ministers of Louis XIV. took infinite and most judicious pains to make their military men superior to all others by their academical education. A more scientific turn was given to their education, and the affluence of scientific men was liberally given them; and all the nations of Europe must acknowledge some obligations to them for information on every thing connected with the art of war. They have attended very much to this subject, have greatly improved it, and have even introduced a new principle into the art; and by this means have reduced it to the most simple form of reference to the code of sailing and fighting instructions, by making the signals immediately expressive, not of orders, but of simple numbers. These numbers being prefixed to the various articles of the code of instructions, the officer who sees a signal thrown out by the admiral reads the number, and reports it to his captain, perhaps without knowing to what it relates. Thus simplicity and secrecy, with an unlimited power of variation, are combined. We believe that M. de la Bourdonnais, a brave and intelligent officer, during the war 1758, was the author of this ingenious thought.

We do not propose to give a system of British signals. This would evidently be improper. But we shall show our readers the practicability of this curious language, the extent to which it may be carried, and the methods which may be practised in accomplishing this purpose. This may make it an object of attention to scientific men, who can improve it; and the young officer will not only be able to read the orders of the commander in chief, but will not be at a loss, should circumstances place him in a situation where he must issue orders to others.