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he shall obtain happiness and avoid misery. He has given to man the power of discerning between good and evil, and a liberty of choice in the use of those means, which lead to happiness or misery. The whole duty of man therefore consists in two things: first, in making constant efforts to ascertain what is the will of God; and, secondly, in obedience to that will when ascertained.

NATURAL PHILOSOPHY. That branch of science which treats of the powers of nature, the properties of natural bodies, and their actions on one another, comprehending under it the several divisions of astronomy, chemistry, electricity, galvanism, hydraulics or hydrostatics, magnetism, mechanics, optics, pneumatics, &c.

NATURE. Of this word, which occurs so frequently, with significations so various and so difficultly defined, Boyle has given the following - explication:-Nature is sometimes used for the author of nature, Natura naturans; as, Nature has made man partly corporeal and partly immaterial: for Nature, in this sense, may be used the word Creator. Nature sometimes means that on whose account a thing is what it is, and is called, as when we define the nature of an eagle: for nature, in this sense, may be used for essence, or quality. Nature sometimes means what belongs to a living creature at its nativity, or accrues to it by its birth, as when we say a man is noble by nature, or a child is naturally froward: this may be expressed by saying, the man was born so, or the thing was generated such. Nature sometimes means an internal principle of local motion, as we say the stone falls, or the flame rises, by nature: for this we may say that the motion up or down is spontaneous, or produced by its proper cause. Nature sometimes signifies the established course of things corporeal, as nature makes the night succeed the day: this may be termed established order, or settled course. Nature means sometimes the aggregate of the powers belonging to a body, especially a living one; as when physicians say that nature is strong, or nature, left to herself, will do the cure: for this may be used constitution, temperament, or structure of the body. Nature is put likewise for the system of the corporeal works of God; as there is no phoenix or chimera in nature: for nature, thus applied, we may use the world, or the universe. Nature is sometimes, indeed commonly, taken for a kind of semi-deity; in this sense it is best not to use it at all.

If I were to propose, continues he, a notion of nature less ambiguous than those already mentioned, and with regard to which many axioms relating to that word may be conveniently understood, I should first distinguish between the universal and the particular nature of things. Universal nature I would define to be the aggregate of the bodies that make up the world in its present state, considered as a principle, by virtue whereof they act and suffer according to the laws of motion prescribed by the Author of all things. And this makes way for the other subordinate notion, since the particular nature of an individual consists in the general nature applied to a distinct portion of the universe; or, which is the same thing, it is a

particular assemblage of the mechanical properties of matter, as figure, motion.

NAUSEA. In Medicine, signifies that slighter degree of sickness at the stomach, which does not actually give rise to a discharge of its contents;a propensity to vomit, which may occur with or without actual puking.

Nausea is produced by various causes; sometimes by those circumstances which act directly upon the stomach itself; sometimes by those which influence the stomach indirectly, through the medium of other organs of the body, with which it is connected by sympathy; and sometimes through the medium of the mind.

The nausea which originates from affections of the stomach itself, occurs under various circumstances. It is not unfrequently one of the symptoms of dyspepsy, or indigestion, and arises either from the irritation of the ordinary food, when that is taken in greater quantity than the enfeebled condition of the stomach is capable of digesting; or from the use of articles of diet which are difficult of solution, which tend to generate acidity or other acrimonious humors, or which offend by some acrid or deleterious quality of their own; or, lastly, from the morbid state of the secreted fluids in the stomach, which irritates its nervous coat, like the offensive substances that are taken in.

But the sympathetic sources of nausea are perhaps still more numerous. The brain is seldom materially affected by any serious irritation or derangement, without deranging the stomach by sympathy: thus, sickness at the stomach is a common symptom of every degree of local injury of the head, in which pressure or concussion of the brain is occasioned; it accompanies inflammation of the brain and its membranes, the pressure of water in the ventricles, or of other morbid effusion or growth within the cranium, as well as the opposite state or inanition of the vessels of the brain, as in syncope, or after great losses of blood.

The influence of the mind alone is likewise capable of exciting nausea and even its ultimate degree, vomiting. The sight, or even the description or imagination, of loathisome and offensive objects and actions, will produce this effect on the stomach of many individuals of refined habits, or who are unaccustomed to such objects.

With respect to the cure of nausea, then, it is obvious, that it will be as various as the causes which induce it; and that it is only in the cases, where it results primarily from derangement of the stomach, that any material success can be obtained by remedies directed to that organ. Ia these cases, the nature of the cause must determine the kind of remedy to be administered. When there is obviously a production of acidity, it will be relieved by the absorbent earths, such as chalk and magnesia, and by the alkalies, as prepared soda, soda water, or potash. The mixture of an alkali with lemon juice, taken in the act of effervescence, affords one of the most effectual means of relief in some cases of sickness, when there is considerable weakness and irritability of the stomach. And in those cases, in which there is also pain in the stomach, especially after taking food, opiates may be given, in combination with aromat

ics, with great advantage. In all such cases, however, it is clear that much must be done by the regulation of diet, both in respect to quantity and quality,—by taking only light and digestible food, in moderate portions, and by using regular and moderate exercise. Let it be observed, too, that the practice of resorting to emetics on all occasions of nausea is injudicious; and probably aggravates the evil ten fold, by augmenting the irritability and feebleness of the stomach, and thus laying the foundation for permanent imbecility in that important organ.

NAUTICAL. An epithet for what belongs to the navy or navigation, as the Nautical Almanac, which in England is published under the direction of the Board of Longitude, for the use of mariners.

NAUTILUS. In Natural History, a simple shell, having no hinge, formed of one continued piece, rolled, as it were, into a spiral form, and having its cavity divided into a great number of cells, by transverse partitions, each of which has a perforation, and is continuous to the others by means of a pipe carried the whole length of the shell.

This animal is famous for using its shell in the manner of a boat, and thus swimming on the surface of the sea.

NAVAL ARCHITECTURE. The science of ship-building, comprehending the theory of delineating marine vessels upon a plane surface, and the art of framing them upon the stocks according to the proportions exhibited in a regular design.

acted on the hurdle more strongly than it would on the sides of the vessel, and thus increased the velocity of its motion very materially. In order to preserve a due balance between the head and the stern, which might otherwise have been destroyed by the action of the hurdle, they caused a stone of considerable magnitude, pierced through the middle, to be suspended by a rope from the stern, which enabled them to swim nearly with an even keel.

The first contrivance to supply the place of a commercial vessel is generally admitted to have been a kind of raft, or collection of trees fastened together with ropes, made from the bark. But as in a structure so rude they were altogether without the power of directing their course, they set about remedying this inconvenience, by putting a few thick planks to the depth of three or four feet in the water between the joists of the trees which composed the raft. These, being raised or lowered at the pleasure of the pilot, served in some measure the purpose proposed. With no better contrivances than this, the Phoenicians are said to have visited the islands of Sicily, Corsica, and various other islands in the Mediterranean. It is also worthy of observation, that floats answering to the description of these were found in the south seas in the last century.

Although the Greeks were not remarkable for a spirit of commercial enterprise, yet the remains of antiquity furnish us with ample evidence of the advances which they made in the art of shipbuilding. They had vessels of different forms and sizes, distinguished, according to their use, into ships of passage, ships of burden, and ships of war. The latter were likewise designated triremes, quadremes, and quinquiremes, according to the number of banks of oars, which were raised in a sloping direction one above another. Those which had most banks were built highest, and rowed with the greatest strength. The Greeks, in all probability, derived their knowledge of shipbuilding from the Carthaginians, a warlike and trading people descended from the Phoenicians, who were celebrated for their skill in the construction and management of vessels. In consequence of their contests with the Romans, the latter, after having suffered one or two defeats in naval engagements, acquired the art of building ships from their rivals, and successfully employed it to their overthrow.

NAVAL ARCHITECTURE, HISTORY OF. The first example of any construction fitted to be borne up by the waters is recorded in Scripture in the case of the ark built by Noah under the divine assistance and commands. As this was built by more than human aid, it is not surprising that we hear of no farther attempts at building vessels of any kind until the nation of the Egyptians was formed, who doubtless profited by those arts and sciences which, as is generally admitted, were practised before the flood, and transmitted by Noah and his family to his posterity. The Egyptians, we are told, constructed the barks which they used on the Nile of planks cut out of the acacia, or Egyptian thorn; the planks were nearly square, measuring about three feet each way, and, being The modern art of ship-building appears to have lapped over each other like tiles, were fastened to-been derived from the northern tribes, among gether with wooden pins. The joints and seams whom we find that trees hollowed out like canoes were carefully calked with the papyrus, and were first used. The crusades first gave the imbenches of the same material were formed for the pulse to improvements in ship-building, which, rowers. As the necessity of some impelling and notwithstanding, continued for some time at a low directing force in aid of human labor was soon ebb. Even in the reign of Edward the First, ships felt, a rudder and a sail were quickly added. The were very insignificant in point of size, for it apsail, which was made of the papyrus, was fastened pears that forty men were deemed sufficient to to a pole serving as a mast, which was made of man the largest vessels in England. The states the acantha. As such vessels were incapable of of Venice and Genoa probably first increased the stemming the current of the river when the wind size of their ships, but they were soon surpassed was unfavorable, they used to be towed by persons by the Spaniards, who first employed cannon. on the bank, and when they went with the current, The Hanse Towns made such advances in naval the Egyptians used to accelerate their motion by architecture, that in the fourteenth century it was tying a hurdle of tamarisk to the prow of the ves-usual for them to let their ships out to foreign sel, and letting it down into the water; the stream | princes. In the reign of Henry IV. ships of con

siderable size began to be built in England, and they continued to increase in magnitude until the reign of Henry VIII. when two very large ships were built, namely, the Regent, of 1000 tons burden, and the Henry Grace Dien, which was larger. From the reign of Charles II. the navy of Great Britain acquired great importance, and in consequence of the wars which have been since carried on in several subsequent reigus, it has risen to its present state.

NAVIGATION. No art or profession has appeared more astonishing and marvellous than that of navigation, in the state in which it is at present. This cannot be made more evident than by taking a retrospective view of the tottering, inartificial craft to which navigation owes its origin: and by comparing them with the noble and majestic edifices now in use, containing a thousand men, with their provisions, drink, furniture, wearing-apparel, and other necessaries for many months, besides a hundred pieces of heavy ordnance, and carrying all this vast apparatus safely, on the wings of the wind, across immense seas.

These majestic floating structures are the result of the ingenuity and united labor of many hundred of hands, and are composed of a great number of well-proportioned pieces of timber, nicely fastened together by means of iron nails and bolts, and rendered so tight with tow and pitch, that no water can penetrate into any part.

To give motion to these enormous machines, lofty pieces of timber called masts, have been fixed upright in them; and sails of linen cloth are placed for the purpose of catching the wind, and receiving its propelling power. It has been requisite also to add vast quantities of cordage and tackling. Yet all these would be insufficient for the perfect government and direction of the vessel, if there were not fastened to the hinder part of it, by means of hinges and hooks, a moveable piece of wood called the rudder, very small in proportion to the whole machine, but the least inclination of which to either side is sufficient to give immediately a different direction to the enormous mass; so that two men may direct and govern this floating town, with the same or with greater ease than a single man can direct a boat.

Even the vaulted part of the fabric, together with its sharp termination underneath, is proportioned according to the nicest calculations; and the length, width, and strength of the sails and tackling, are all in due proportion to one another, according to certain rules founded upon the principles of the art of ship-building.

dinary and surprising task of him who is skilled in the science of navigation.

A violent storm of wind will make us tremble with fear in a well-built house, in the midst of a populous city; but the seaman, provided he has a good ship, rides with unshaken courage, amidst the enraged waves, when the whole surface of the ocean presents to the eye an awful scene of immense watery mountains and bottomless precipices. NAVIGATOR. One who follows the practical part of navigation; particularly one who goes on voyages of discovery.

NAVY. The ships of war which belong to a nation, as its public property; divided into ships of the line, or those above 60 guns, frigates from 50 to 28 guns; and sloops and cutters, from 28 to 6 guns.

NAZARENES. A name sometimes given to the first Christians by their adversaries, and, even to this day, there exist, in Eastern Asia, some Christian congregations under this name. The sect of Nazarenes, which originated as early as the second century, in Palestine, believed it was necessary to unite the Jewish ceremonial law with the precepts of Jesus, and refer to a Hebrew Gospel of Matthew. The Ebionites (the poor) went still further in the observance of the Mosaic law, rejected, at the same time, the Epistles of St. Paul, and doubted the divinity of Christ, whom they considered but a perfect man. Like the Nazarenes, with whom they have a common country, and time of origin, but are by no means to be confounded, they had a Hebrew original Gospel. Both sects were unimportant, and seem to have ceased in the fourth century.

NAZARITES. Among the Jews: persons who devoted themselves to the peculiar service of Jehovah, for a certain time, or for life. During their vow, they did not cut their hair, or drink any strong drink, or approach a dead body. It was foretold of Samson, that he should be a Nazarite unto God from the womb. So Hannah vowed her first born son (Samuel) to Jehovah all the days of his life, with the promise that no razor should come near his head.

NEALING, or ANNEALING. In the Arts, consists in making metals redhot, which have become hard and brittle by working, in order to restore their former malleability and tractability. All metals have the property of becoming more or less A large ship carries at least 2200 tons burden, hard and unmalleable, after undergoing the operathat is, 4,500,000lb., and at the same time is steered tion of the hammer. Metals thus affected are and governed with as much ease as the smallest more elastic than they were before, but, at the boat. And yet if such a ship sailed along the coast same time, they become more brittle. They are only, and, like the navigators of old, never lost the more sensibly affected in this manner in prosight of the shore, we might still look on naviga- portion as the metals are naturally harder. Copper tion as an easy business. But to find the shortest is so much affected, and even gold and silver, by way across an ocean from 4000 to 6000 miles in width, sailing by day or by night, in fair weather or in foul, as well when the sky is overcast, as when it is clear, with no other guide than the compass, or the height of the sun, the moon and stars, with exactness and precision, is the extraor

hammering and compression, that they soon cease to be malleable, and instead of being extended under the hammer they crack and split. Hence the necessity of annealing the common coins of the country. In all cases the labor of hammering, when it is to be long continued, must occasionally

be interrupted to soften and restore malleability to metals; this is effected by making them redhot, and suffering them to cool gradually. Thus heat produces the same effect on metals, in the state described, as it does upon tempered steel, for, if the hardest tempered steel be made redhot and cooled slowly, it becomes as tractable and ductile as the softest iron. Articles of glass are also nealed before they are fit for use, by placing them in a furnace, and after they have been raised to a due degree of temperature, they are suffered to cool gradually. Without this operation glass vessels would be entirely useless, as they would not admit of the least change of temperature from cold to heat, nor would they bear the slightest blow.

NEAP TIDES. Tides in the second and last quarter of the moon, not so high as the spring tides.

NEBULE. In Astronomy. There are spots in the heavens called nebulæ, some of which consist of clusters of telescopic stars, others appear as luminous spots of different forms.

tance. The milky way consists entirely of stars; and he says, 'I have been led on by degrees from the most evident congeries of stars to other groups in which the lucid points were smaller, but still very plainly to be seen; and from them to such wherein they could but barely be suspected, until I arrived at last to spots in which no trace of a star was to be discerned. But then the gradation to these latter were by such connected steps as left no room for doubt, but that all these phenomena were equally occasioned by stars variously dispersed in the immense expanse of the universe."

In the same paper is given an account of some nebulous stars, one of which is thus described, 'Nov. 13, 1790. A niost singular phenomenon! A star of the eighth magnitude, with a faint luminous atmosphere of a circular form, and of about three in diameter. The star is perfectly in the centre, and the atmosphere is so diluted, faint, and equal throughout, that there can be no surmise of its consisting of stars, nor can there be a doubt of the evident connexion between the atmosphere and the star. Another star, not much less in brightness, and in the same field of view with the Dr. Halley and others have discovered nebula above, was perfectly free from any such appearin different parts of the heavens. But to Dr. Her-ance.' Hence, Dr. Herschel draws the following schel we are indebted for catalogues of 2000 nebu- consequences: granting the connexion between læ, and clusters of stars, which he himself has dis- the star and the surrounding nebulosity, if it concovered. Some of them form a round compact sist of stars very remote, which gives the nebulous system, others are more irregular, of various forms, appearance, the central star, which is visible, must and some are long and narrow. The globular be immensely greater than the rest; or if the censystems of stars appear thicker in the middle than tral star be no bigger than common, how extremely they would do if the stars were all at equal distan- small and compressed must be those other luminces from each other; they are, therefore, conden-ous points which occasion the nebulosity. As, by sed toward the centre. That stars should be thus the former supposition, the luminous central point accidentally disposed is too improbable a supposi- must far exceed the standard of what we call a tion to be admitted; he supposes, therefore, that star; so in the latter, the shining matter about the they are brought together by their mutual attrac- centre will be too small to come under the same tions, and that the gradual condensation towards denomination; we, therefore, either have a central the centre is a proof of a central power of such a body which is not a star, or a star which is involkind. He observes, also, that there are some ad-ved in a shining fluid, of a nature totally unknown ditional circumstances in the appearance of exten- to us. This last opinion Dr. Herschel adopts. ded clusters and nebula, that very much favor the idea of a power lodged in the brightest part. For NECESSITY. Necessity, is a term that has although the form of them be not globular, it is been much used by modern writers; and which plain that there is a tendency to sphericity. As some have defined to be, that by which a thing the stars in the same nebulæ must be very nearly cannot but be, or whereby it cannot be otherwise. all at the same relative distances from us, and they But a much approved author on this subject obappear nearly of the same size, their real magni- jects against this definition, and observes, that philtudes must be nearly equal. Granting, therefore, osophical necessity is really nothing else than the that these nebula and clusters of stars are formed full and fixed connexion between the things signiby mutual attraction, Dr. Herschel concludes, that fied by the subject and predicate of a proposition, we may judge of their relative age by the disposi- which affirms something to be true; so that it is tion of their component parts, these being the old-in no respect different from their certainty. When est which are most compressed. He supposes, there is such a connexion, then the thing affirmed and indeed offers powerful arguments to prove, in the proposition is necessary in a philosophical that the milky way is the nebule of which our sun is one of its component parts.

sense; whether any opposition or contrary effort be supposed or supposable in the case or no, When the subject and predicate of the proposition, which affirms the existence of any thing, either substance, quality, act, or circumstance, have a full and certain connexion, then the existence of that thing is said to be necessary in a metaphysical

Dr. Herschel has also discovered other phenomena in the heavens, which he calls nebulous stars; that is, stars surrounded with a faint luminous atmosphere of large extent. Those which have been thus styled by other astronomers, he says, ought not to have been so called, for on examina-seuse. tion they have proved to be either mere clusters of stars plainly to be distinguished by his large telescopes, or such nebulous appearances as might be occasioned by a multitude of stars at a vast dis

NECKLACE. An ornamented string of gold beads, or precious stones, worn round the neck, The Egyptians were early habituated to the use of

the necklace, as is proved from the greater number of their ancient statues, even those of men: sometimes these necklaces are found encrusted in silver upon statues of bronze. The Greek and Roman ladies loved to appear thus ornamented, particularly in feasts and dances. The Spaniards wore collars of iron. The Roman generals were wont to distribute necklaces solemnly among such soldiers as were distinguished by their valor and good conduct, and who were hence called milites torquati. These torques were frequently made of gold or of silver. The Gauls wore collars or necklaces of precious metal in their armies. Manlius received his well known surname, Torquatus, from having despoiled a Gaul of one of these ornaments whom he had killed in single combat.

NECROLOGY. A register of the deaths of benefactors in a monastery; also a register of distinguished persons who die within a certain period.

NECROMANCY. A sort of magic practised by the Jews, Greeks, and Romans, by which they attempted to raise the dead or make them appear.

NECTAR. Among the Poets, the drink of the gods, in contradistinction to their solid food, which was called ambrosia. The word is also used by some of the ancients, to express honey.

man traffic called the slave trade. They are very numerous in the central parts of Africa, and it appears by the late Travels of Denham and Clapperton and others, that powerful kingdoms exist there, in a state further advanced toward civilisation, than was supposed. It has been imagined that the negroes are inferior in capacity to the other races of mankind, but a better knowledge of Africa may throw doubt upon this opinion.

NEPHRITE. In Mineralogy, a species of the tale genus; it is also called jade, or jade-stone. It was formerly celebrated for its medical virtues. It is of a dark leek-green color, verging to blue. It occurs massive in detached rounded pieces. Nephrite is found in Egypt, China, America, the islands in the Pacific Ocean, and in the Siberian mountains sometimes adhering to rocks, and sometimes in detached round pieces. It is highly prized by the Hindoos and Chinese, by whom it is made into talismans and idols, and by the Turks who form it into sword and dagger handles.

NERVE. Nerves are long, white, medullary cords, that serve for sensation. They originate from the brain and spinal marrow. Hence they are distinguished into cerebral and spinal nerves, and are distributed upon the organs of sense, the viscera, vessels, muscles, and every part that is endowed with sensibility.

NECTARIUM. In Botany, that which is NERVOUS FLUID. The vascularity of the sometimes only a part of the corolla, and some-cortical part of the brain, and of the nerves themtimes, though more rarely, the whole. It is a part destined for the reception of the honey juice of the plant, and is very various in its figure.

selves, their softness, pulpiness, and natural humid appearance, give reason to believe, that, between the medullary particles of which they are principally composed, a fine fluid is constantly secreted, which may be fitted to receive and transmit, even more readily than other fluids do, all impressions which are made on it.

NEEDLE. A name given to various small instruments in the useful arts. The most common acceptation of the word is to denote the common sewing-needle, which is so well known as to require no description: beside this there is the knit- NEST. A bed or habitation where animals ting-needle; the netting-needle; the glovers-nee-rear their young. The exquisite ingenuity which die, with a triangular point; the tambour-needle, various creatures display, in constructing their which is made like a hook and fixed in a handle; nests, has always been a subject of deserved admithe hook being thrust through the cloth, the thread ration. is caught under the hook, and the needle is drawn back, taking the thread with it. Needle is a name given to a part of the stocking-frame, lace-machine, and many other machines in the manufactures.

NETTLE-RASH. In medicine, a troublesome cutaneous eruption, of which Dr. Cullen forms the genus urticaria. The disease has its English name from the resemblance of its eruption to that made

NEEDLE, MAGNETICAL. A needle touch-by the stinging of nettles. These little elevations ed with the loadstone, and suspended on a pivot, on which, playing at liberty, it directs itself to the north and south of the horizon. Magnetical needles are called horizontal when balanced equally on both sides, and inclinatory or dipping when they are constructed so as to show the dip of the needle, or how far it points below the horizon.

NEGATIVE ELECTRICITY. That state of bodies, in which they are deprived of some portion of the electricity which they naturally contain.

NEGROES. The black inhabitants of Africa, having woolly hair and a peculiar complexion. They have hitherto been the objects of the inhu

upon the skin in the nettle-rash often appear instantaneously, especially if the skin be rubbed or scratched, and seldom stay many hours in the same place, and sometimes not many minutes. No part of the body is exempt from them; and where many of them rise together, and continue an hour or two, the parts are often considerably swelled; which particularly happens in the face, arms, and hands. These eruptions will continue to invest the skin, sometimes in one place and sometimes in another, for one or two hours at a time, two or three times every day, or perhaps for the greatest part of the twenty-four hours. In some persons they last only a few days, in others many months; nay sometimes the disease has lasted for years, with very short intervals.

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