arrangement. These night signals and instructions, thus prepared and comprised, with indices, in one small octavo volume, were then adopted, and have ever since been used in his majesty's navy. As it may be deemed improper to give publicity to these night signals, or to exhibit in this work a detail of the principles on which they are founded, suffice it to observe that the utility of the plan, compared to that formerly in practice by showing lights at particular parts of a ship, or in the form of triangles, squares, or lozenges, where best seen, is too obvious to be dwelt upon; yet, when a fleet is in the presence of an enemy, it may be proper to make signals in the night by lights only.

Lord Hood, knowing well how to appreciate every improvement in naval tactics, was the first commander-in-chief of a fleet who issued to the flag-officers of squadrons and captains of ships under his orders, at the commencement of the war in 1793, the New Arrangement of Day and Night Signals above noticed; and their utility since that period has been confirmed by the practice and experience of every successive commander-in-chief. From the observations of many intelligent officers, it was found that the code of numerary night signals, although it had advantages in some respects over every other known mode practised, yet there was a desideratum sought after, namely, to give privacy to night signals when in expectation of falling in with an enemy, or approximating the line of an enemy's coast. It is, therefore, the object of the following auxiliary plan, proposed by Mr. M'Arthur, to remedy the disadvantages that might eventually result by firing guns, as the component part of the numerary combination to night signals, and which may still be continued as the standing system, when the fleet is not in expectation of falling in with the enemy. This can be effected by the combinations of four distinct lights, with out the aid of guns or false fires; and the mode proposed will have the superadded advantage of being occcasionally employed as a nocturnal telegraph, for naval or military purposes.

General principles to be adopted.

1. An improvement in the construction of signal lanterns; and, as only four are required for each ship, they ought to be issued as an article of store by the navy office.

2. The signals are to be made from on board ship where best seen, forward or abaft; or if a ship be directly a-head or a-stern of other ships to whom these signals are to be communicated. The signal lanterns may be shown at the larboard and starboard yard-arms, where best seen; but, if used on shore, the left hand post or signal staff; and the right hand post or staff, are to be considered synonymous terms to the application, at sea, of forward and abaft, or larboard and starboard yard-arms.

3. The combination of two, three, or four lights, shown at sea forward or abaft, or at the larboard and starboard yard-arms; but, if on

shore, hoisted on the left post or right, together with one or two obscurations of the lights, either in a horizontal or vertical position, will denote more ideas than is required for any code of night signals.

The lanterns are to be made in a cylindrical form; dimensions about nine inches diameter, and proportionable height. A lamp with four burners is to be placed in a socket in the centre, and so constructed that, if a lantern should happen to be upset, the oil cannot be spilt. Instead of horn or glass to the lanterns it is proposed to substitute talc, or what is commonly known by the name of Muscovy glass, which is equally as transparent as common glass, is much lighter; and will not consume by fire.

Each lantern to have an obscurer of tin or canvas, to denote the combinations to be hereafter explained. These obscurers to be in the form of cylinders, perforated with air-holes at the tops and open at the bottoms so as to encircle or cover the lanterns, and thereby eclipse the lights when necessary.

The obscurations, or eclipses, of the lights, are thus practised with facility:-Suppose the four lights hoisted vertically, or one over the other, at the usual distance of ten or twelve feet asunder, each lantern to have its obscurer placed from five to six feet over it, and, by a line passing through a small block attached to the lantern halyards, any of the lights at the word of command would be obscured. In exposing the light again, it is only necessary to haul the topping line of the obscurer, while the lantern remains in the same permanent situation.

The lanterns and mode of obscuring the lights being premised, the plan is susceptible of the following arrangement:-The first will denote, as by preparatory signal, that the combinations are to be applied telegraphically, to the letters of the alphabet. The second arrangement will denote, by preparatory signal, the first twenty-five numbers allotted to the significations in the standing Night Signal book for the navy, and in order to express fifty additional numbers, making in all seventy-five signals, which is more than the numerary code with guns, lights, and false-fires compréhend, an obscuration of one light for an interval of twenty or thirty seconds will denote the numbers from 26 to 50 inclusive; and the obscuration of two lights will denote the numbers from 51 to 75 inclusive, as expressed in the following table:-The open cyphers, thus O, in the annexed table, denote the lights shown, and the shaded ones, thus denote the lights o scured or eclipsed.

It is to be observed that, when one or two lights are to be obscured, the lights composing the signal are first shown for a few minutes; then one or two lights, as indicated in the table, to be obscured for twenty or thirty seconds, and which is to be repeated by showing the lights again until answered and understood by the ships to which the signal may be addressed.

Explanation of the table.-Each lantern-light to four expresses 1, 2, 3, 4, respectively. One blue-light expresses 5. Two guns express 10, three guns express 20, and four guns 30. To express any number, therefore, as for instance 19, fire two guns, burn one blue-light, and hoist four vertical lights where they can best be seen.

Previous to making any of the first nine signals, which do not require guns to express the number, one gun will be fired to draw the attention of the fleet, and in making the remaining signals, the necessary guns will be fired to draw the attention of the fleet previous to hoisting the lights, or burning the blue-light. To prevent a confusion of lights, when a signal is made from the commodore, the top light will be covered.

It is recommended to use glass signal-lanterns, as horn admits a very dull light. Such lanterns should be well strengthened down the sides, and be provided with a secure ring at the bottom as well as at the top, for the convenience of bending them to each other; and to the top ring of three of the signal-lanterns a tack should be fitted, about a fathom long, to admit their being bent to each other with regularity and despatch.

SIGNAL, PREPARATORY (Fr. signal préparatoire), a signal given by the admiral to the whole, or any part of his fleet, and is immediately answered by those to whom it is directed; by showing the same signal, to testify that they are VOL. XX.

ready to put his orders in execution. Having observed their answer, he will show the signal which is to direct their operations: as, to chase, to form the line, to begin the engagement, to board, to double upon the enemy, to rally or return to action, to discontinue the fight, to retreat and save themselves. The dexterity of working the ships in a fleet depends on the precise moment of executing these orders; and on the general harmony of their movements: a circumstance which evinces the utility of a signal of preparation.

As the extent of the line of battle, and the fire and smoke of the action, or other circumstances in navigation, will frequently prevent the admiral's signals from being seen throughout the fleet, they are always repeated by the officers next in command; by ships appointed to repeat signals; and, finally, by the ship or ships for which they are intended.

The ships that repeat the signals, besides the chiefs of squadrons or divisions, are usually frigates lying to windward or to leeward of the line. They should be extremely vigilant to observe and repeat the signals, whether they are to transmit the orders of the commander-in-chief, or his seconds, to any part of the fleet, or to report the fortunate or distressful situation of any part thereof. By this means all the ships from the van to the rear will, unless disabled, be ready