If one of the objects is the sun, and the other the moon, it will generally be necessary to put down one of the dark glasses, D. And, with the moon and a star, it will often be necessary to put down one of the lighter of the screens D, to reduce the glare of the moon's light, that the star may be distinctly enough seen when in contact with the moon's image. The nearest limbs of the sun and moon are always brought in contact, and the enlightened or round limb of the moon is always brought in contact with a star, and, by applying the known semi-diameters, the central distance of the object is obtained. It is much more easy to observe with the face of the instrument upwards than downwards, though this latter position, in the method of observing detailed above (that which is almost universally practised), must necessarily be as sumed when the dimmer object is to the right. But the writer of this article in such circumstances frequently puts one or more of the dark glasses, F, before the horizon glass, and, removing those at D from before the index glass, looks directly at the brighter object, and takes the dimmer one by reflection. In this case, how ever, it is necessary to bring the telescope near the plane of the instrument by means of the screw attached to X, the stem of the collar G, that a considerable portion of the object glass of the telescope may be opposite the silvered part of the horizon glass. In taking distances with the reflecting circle, hold the instrument by the handle H, fig. 3, plate III; and looking through the telescope and the horizon glass T at the dimmer object, move forward the index QPQ' till the image of the brighter one, as seen by reflection from A B, the index glass, appear in contact with the dimmer one seen directly, and, clamping the screw Z, make the contact perfect by means of either of the screws Q, Q. Then, taking the instrument by the handle H", turn the graduated side of the instrument upwards, and read the degrees, minutes, &c., at the vernier attached to the index QPQ, but the minutes, &c., only at the vernier's attached to C', C". Next take the instrument by the handle H", and, reversing it, point the teleScope again towards the dimmer object, and moving forward the leading index QPQ', make the contact perfect, and read the verniers as before. Then the sixth part of the sum of the readings will be the distance independent of index error, which, when the instrument is used in this manner, has no existence, as each of the indexes passes over twice the arch to be measured, the leading one to the right and left of zero, and the others in equal quantity on different parts of the arch. The microscopes M', M", &c., are brought in reading round to the verniers of the indexes to which they are attached. NAVIGATOR'S ISLANDS, a cluster of ten lofty islands in the South Pacific Ocean; some of which are well-peopled and remarkable for their extent and fertility. They are situated between 169° and 172° 30° W. long., and from 13° 25′ to In taking altitudes with a sextant or circle, by an artificial horizon, the telescope is pointed to the image of the object as reflected from the surface of a fluid, or a polished plane set horizontally by means of levels; and the image of the object as reflected from the index glass to the horizon glass, and hence to the eye through the telescope, is brought in apparent contact with the image of the object as seen by reflection from the horizontal plane; and the distance of these two images is double the altitude of the object. In all cases it is recommended to use the inverting or astronomical telescope. The direct telescope is in general simply an opera glass, without means of ascertaining the position of its line of collimation; and its field of view is necessarily small, as that of all telescopes constructed on such principles must be. A very little practice will render the use of the inverting telescope easy. We have now only to describe the method of adjusting the back horizon glass of the quadrant G, fig. 1, plate III. To do this, place the zero of the index to the right of zero, on the limb, a quantity equal to twice the dip; then looking through the sight vane I, and the slit in the middle of G at the horizon, move the glass G by means of the lever at the back of the instrument till the opposite horizon, or that behind the observer, appear in a line with that seen directly through the transparent slit. Incline the instrument to the horizon, and, if the horizon seen directly and by reflection do not then coincide, adjust by the screws before and behind the glass, as in adjusting E, till they appear to coincide in all positions of the instrument; then the back-horizon glass G will be perpendicular to A B when the index is at zero, and also perpendicular to the plane of the instrument. To take an altitude by a back observation, look through the right vane F, fig. 1 plate III., and the transparent slit in the middle of the back horizon glass G, at that part of the horizon opposite to the sun; and, moving the index K Q, the image of the sun will appear to ascend; make the contact perfect in the same way as in the fore observation. The apparent upper limb of the object is its real lower limb. The distance of any two celestial objects may be measured with a quadrant, though not with the same nicety as it may be done with a sextant; if, however, the distance is more than 90°, it must with the quadrant be measured by a back observation, which is done by looking at the dimmer object, and moving the index till the reflected image of the other appears to coincide with it; when the supplement of the angle shown by the index on the limb of the instrument will be the required distance of the objects. NAVIGATION, INLAND. See INLAND NAVI GATION. NAVIGATION LAW. See MARITIME LAW. an uncertain fat. southward. The easternmost of the cluster seem to have been discovered by Roggewein and Bauman in 1722; another of magnitude was added by Bougainville in 1768, and the two westernmost, which are the most consi siderable, were first seen by Perouse in 1787. Each of the last is more than forty miles in length. They all were visited by Edwards in 1791. Perouse mentions three more of which he heard to the southward, named Sheka, Ossamo, and Ooera. He speaks of the inhabitants of these islands as stout and well-made men, their ordinary height being five feet nine, ten, or eleven inches. Their bodies are painted or tatooed round their loins they wear a girdle of sea-weed, which reaches to their knees. Their hair is very long, and frequently turned up all round the head, so as to heighten, say the simple navigators, the ferocity, or, as we might say, the dandyism, i. e. (so do extremes meet) the Bond Street refinement of their countenances; which always express astonishment,' we are told, 'or choler!' The least dispute between them is followed by violence: and often costs the combatants their lives; they are most universally, therefore, covered with scars, the consequences of these quarrels. The manners of both male and female are disgustingly profligate. They dis dained the iron tools which were offered them in exchange for produce, and use hatchets shaped like adzes, made of a very fine basaltes. The chief food is roots, hogs, and poultry: and they manufacture a good sail-cloth for their canoes; which are also well-built and ornamented. NAVY is used for the fleet or shipping of a prince or state. See MARINE. The management of the British royal navy, under the lord high admiral of Great Britain, is often entrusted to principal officers and commissioners, who hold their places by patent. The royal navy of Great Britain is now in a very flourishing state, having been diligently kept up in late reigns, as the natural strength of the kingdom. When it is complete, it is divided into three squadrons, distinguished by the colors of the flags carried by the respective admirals belonging to the same, viz. red, white, and blue; the principal commander of which bears the title of admiral and each has under him a vice-admiral and a rear-admiral, who are likewise flag-officers. NAVY. In our statistics of GREAT BRITAIN we have given an account of the rise and progress of this important source of our national strength and greatness. Our article SHIP-BUILDING will enter fully into what the French call the materiel of this part of the service. We here notice may 1. The present rating of the navy.-To remedy the inconveniences resulting from the different scales formerly adopted in the measurement of ships, the lords of the admiralty suggested, by their memorial to the prince regent, the present rating, which, by his order in council, of the 25th November 1816, was ordered to be carried into effect, i. e. that the ships of the navy should for the future be rated as under:The first rate to include all three-deckers, inasmuch as all sea going ships of that description carry 100 guns and upwards; the second rate to include all ships of eighty guns and upwards, on two decks; the third rate to include all ships of seventy guns and upwards, and less than eighty guns: the fourth rate to include all ships of fifty guns and upwards, but less than seventy guns: the fifth rate to include all ships from thirty-six Of sloops the complements established according 2. The personel of the navy, properly so called.— This consists of the commissioned officers; i. e. the flag-officers, post-captains, commanders, and lieutenants; the warrant-officers, petty officers, and seamen. Flag-officers are divided into those of the three squadrons, red, white, and blue, each of which has three ranks of flag-officers; as admiral of the red, white, or blue; vice-admiral of the red, white, or blue; rear-admiral of the red, white, or blue; the admiral wearing his color at the main, the vice-admiral at the fore, and the rear admiral at the mizen-mast-head. There is also an admiral of the fleet, who, if in command, would carry the union flag at the main. There are besides superannuated rear-admirals, enjoying the rank and pay of a rear-admiral, but incapable of rising to a higher rank. There is also in the navy the temporary rank of commodore, generally an old post-captain, and distinguished by wearing a broad pendant. He ranks next to the junior rear-admiral, and above all post-captains, except where the captain of the feet shall be a post-captain, who, in that situation, takes rank next to the junior rear-admiral. The warrant officers are the master, second master, gunner, boatswain, carpenter. There are other warrant officers, who, though noncombatants, constitute a part of the establishment of the larger classes of ships of war. These are, the chaplain, surgeon, surgeon's assistant, purser. To which may be added, as part of the staff of a fleet or squadron, secretary to the admiral or commander-in-chief, and physician of the fleet. The petty officers are very numerous, the principal of whom are master's mates and midshipmen. Their names or ratings will be seen in the following table of the establishment of the ratings and pay in the different classes of ships of war. The officers of the navy thus rank with those of the army: Officers of the same rank command according to the priority of their commissions, or, having commissions of the same date, according to the order in which they stand on the list of the officers of the navy, except in the case of lieutenants of flag-ships, who take precedence according as the flag-officer shall think fit to appoint them. Midshipmen are required to serve six years on board some of his majesty's ships, two of which years they must have been rated as midshipmen, to render them eligible to the rank and situation of lieutenant; or, if educated at the Royal Naval College, four years' service at sea qualify for a commission as lieutenant. No lieutenant can be promoted to the rank of commander, until he has been on the list of lieutenants for two years; and no commander to the rank of post-captain until be has been on the list for one year. Postcaptains become admirals in succession, according to their seniority on the list; but, if a postcaptain should not have served in the course of the preceding war, when his turn arrives he is passed over, and placed on the list of superannuated and retired captains; as are those captains likewise who have accepted of commissionerships or other civil employments, provided they retain those employments when they come within the limits of a promotion to the rank of rear-admiral. No person can be appointed to serve as master of one of his majesty's ships who shall not have served as second master; and no person can be appointed as second master, until he has passed such examination as may from time to time be directed. No person can be appointed gunner or boatswain, unless he shall have served one year as a petty officer on board one or more of his majesty's ships, and produce certificates of his good conduct, and undergo the necessary examination. No person can be appointed carpenter, unless he shall have served an apprenticeship to a shipwright, and been six months a carpenter's mate on board one or more of his majesty's ships. No person can be appointed purser, unless he shall have been rated and discharged the duties of a captain's clerk for two complete years, one year as captain's clerk, and been employed in the office of the secretary to a flag-officer for one other year, produce good certificates, and find such security for the honest and faithful discharge of his duty as shall be required. No person can be appointed chaplain to one of his majesty's ships, until he has received priest's orders; but may be appointed to act while in deacon's orders. No person can be appointed surgeon to one of his majesty's ships, until, by long and meritorious services, he has discharged the duties of assistant surgeon; and all persons applying for the situation of assistant surgeon must undergo an examination touching their qualifications before the medical members of the victualling board. All flag-officers, commanders-in-chief, are considered as responsible for the conduct of the fleet or squadron under their command; to keep them in perfect condition for service; to exercise them frequently in forming orders of sailing and lines of battle, and in performing all such evolutions as may occur in the presence of an enemy; to di rect the commanders of squadrons and divisions; to inspect into the state of each ship under their command; to see that the established rules for good order, discipline, and cleanliness, be observed; and occasionally to enquire into these and other matters themselves. They are to correspond with the secretary of the admiralty, and report to him all their proceedings for the information of the board. If a commander-in-chief should be killed in battle, his flag is to be continued flying; intelligence to be conveyed by signal, or otherwise, to the next in command, who is immediately to repair on board, leaving his own flag (if a flag-officer) flying, and direct the operations of the fleet until the battle be ended, or the enemy out of sight. Every flag-officer serving in a fleet, but not commanding it, is to superintend all the ships of the squadron or division placed under his orders; to see that their crews are properly disciplined; that all orders are punctually attended to; that the stores, provisions, and water, are kept as complete as circumstances will admit; that the seamen and marines are frequently exercised; and that every precaution is taken for preserving the health of their crews; for all which he is responsible to the commander-in-chief. When at sea, he is to take care that every ship in his division preserve her station, in whatever line or order of sailing the fleet may be formed; and in battle he is to observe attentively the conduct of every ship near him, whether of the squadron or division under his immediate command or not; and at the end of the battle he is to report it to the commander-in-chief, in order that commendation or censure may be passed as the case may appear to merit; and he is empowered to send an officer to supersede any captain who may misbehave in battle, or whose ship is evidently avoiding the engagement. If any flag-officer be killed in battle, his flag is to be kept flying, and signals to be repeated, in the same manner as if he were still alive, until the battle shall be ended; but the death of a flag-officer, or his being rendered incapable of attending to his duty, is to be conveyed as expeditiously as possible to the commander-in-chief. When a captain is appointed to command a ship of war, he commissions the ship by hoisting his pendant; and if fresh out of the dock, and from the hands of the dock-yard officers, he proceeds immediately to prepare her for sea, by demanding her stores, provisions, guns, and ammunition, from the respective departments, according to her establishment. He enters such men as may volunteer, and be fit for the service (in time of peace), or which may be sent to him from some rendezvous for raising men, in time of war; and he gives them the several ratings of petty officers, able-seamen, ordinary, or landsmen, as their apparent qualifications may entitle them to. If he should be appointed to succeed the captain of a ship already in commission, he passes a receipt to the said captain for the ship's books, papers, and stores, and becomes respon. sible and accountable for the whole of the remaining stores and provisions; and, to enable him to keep the ship's accounts, he is allowed a clerk of his own appointing. The th |