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hundred and seventy-six degrees, dissolve only 29. On being exposed to a gentle heat nitre fuses; and in this state being poured into moulds, so as to form little round cakes, or balls, it is called sal prunella, or crystal mineral. . This at least is the way in which this salt is now usually prepared, conformably to the directions of Boerhaave ; though in most dispensatories a twenty-fourth part of sulphur was directed to be deflagrated on the nitre, before it was poured out. This salt should not be left on the fire after it has entered into fusion, otherwise it will be converted into a nitrate of potash. If the heat be increased to redness, the acid itself is decomposed, and a considerable quantity of tolerably pure oxygen gas is evolved, succeeded by nitrogen. This salt powerfully promotes the combustion of inflammable substances. Two or three parts mixed with one of charcoal, and set on fire, burn rapidly; azote and carbonic acid gas are given out, and a small portion of the latter is retained by the alkaline residuum, which was formerly called clyssus of nitre. Three parts of nitre, two of subcarbonate of potash and one of sulphur, mixed together in a warm mortar, form the fulminating powder; a small quantity of which, laid on a fire shovel and held over the fire till it begins to melt, explodes with a loud sharp noise. Mixed with sulphur and charcoal, it forms gunpowder. See GUNPowDErt. Three parts of nitre, one of sulphur, and one of fine saw-dust, well mixed, constitute what is called the powder of fusion. If a bit of base copper be folded up and covered with this powder in a walnut shell, and the powder be set on fire with a lighted paper, it will detonate rapidly, and fuse the metal into a sole of sulphuret, without burning the shell. If nitrate of potash be heated in a retort, with half its weight of solid phosphoric or boracic acid, as soon as this acid begins to enter into fusion, it combines with the potash, and the nitric acid is expelled, accompanied with a small portion of oxygen gas and nitric oxide. Silex, alumine, and barytes, decompose this salt in a high temperature by uniting with its base, as was observed when speaking of aqua fortis. The alumine will effect this, even after it has been made into pottery. The uses of nitre are various. Beside those already indicated, it enters into the

composition of fluxes, and is extensively employed in metallurgy; it serves to promote the combustion of sulphur in fabricating its acid; it is used in the art of dying ; it is added to common salt for preserving meat, to which it gives a red hue; it is an ingredient in some frigorific mixtures; and it is prescribed in medicine, as cooling, febrifuge, and diuretic, and some have recommended it, mixed with vinegar, as a very powerful remedy for the sea scurvy.

Nitrate of soda, formerly called cubic or quadrangular nitre, approaches in its properties the nitrate of potash; but differs from it in being somewhat more soluble in cold water, though less in hot, which takes up little more than its own weight; in being inclined to attract moisture from the atmosphere; and in crystallizing in rhombs, or rhomboidal prisms. It may be prepared by saturating soda with the nitric acid, by precipitating nitric solutions of the metals, or of the earths, except barytes, by soda ; by" lixiviating and crystallizing the residuum of common salt, distilled with three-fourths its weight of nitric acid; or by saturating the mo: ther waters of nitre with soda instead of potash.

This salt has been considered as useless; but professor Proust says, that five parts of it with one of charcoal and one of sulphur, will burn three times as long as common powder, so as to form an economical composition for fireworks.

Nitrate of strontian may be obtained in the same manner as that of barytes, with which it agrees in the shape of its crystals, and most of its properties. It is much more soluble, however, requiring but four or five parts of water according to Vauquelin, and only an equal weight according to Mr. Henry. Boiling water dissolves nearly twice as much as cold. Applied to the wick of a candle, or added to burning alcohol, it gives a deep red colour to the flame. On this account it might be useful, perhaps, in the art of pyrotechny.

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boiled down to a syrupy consistence, and exposed in a cool place, it crystallizes in long prisms, resembling bundles of nee

dles diverging from a centre. . These are soluble, according to Henry, in an equal weight of boiling water, and twice their weight of cold; soon deliquesce on exposure to the air; and are decomposed at a red heat. Fourcroy says, that cold water dissolves four times its weight, and that its own water of crystallization is sufficient to dissolve it at a boiling heat. It is likewise soluble in less than its weight of alcohol. By evaporating the aqueous solution to dryness, continuing the heat till the nitrate fuses, keeping it in this state five or ten minutes, and then pouring it into an iron pot previously heated, we obtain Baldwin's phosphorus. This, which is, perhaps, more properly nitrate of lime, being broken to pieces, and kept in a phial closely stopped, will emit a beautiful white light in the dark, after having been exposed some time to the rays of the sun. At present no use is made

Prismatic Fibrous Compact

All these are completely deliquescent, but they differ a little in solubility. Alcohol at 176° dissolves nearly 90.9 of its own weight. The chief use of this salt is for affording nitrous oxide on being decomposed by heat. See nitrous oxide under the art. GAs. Nitrate of magnesia, magnesian nitre, crystallizes in four-sided rhomboidal prisms, with oblique or truncated summits, and sometimes in bundles of small needies. Its taste is bitter, and very similar to that of nitrate of lime, but less pungent. It is fusible, and decomposable by heat, giving out first a little oxygen gas, then nitrous oxide, and lastly nitric acid. It deliquesces slowly. It is soluble in an equal weight of cold water, and in but little more hot, so that it is scarcely crystallizable but by spontaneous evaporation. The two preceding species are capable of combining into a triple salt, an ammoniaco-magnesian nitrate, either by uniting the two in solution, or by a partial decomposition of either by means of the base of the other. This is slightly inflammable when suddenly heated: and by a lower heat is decomposed, giving out oxygen, azote, more water than it contained, nitrous oxide, and nitric acid. The resi

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of this salt, except for drying some of the gases by attracting their moisture; but it might be employed instead of the nitrate of potash for manufacturing aquafortis. The nitrate of ammonia possesses the property of exploding, and being totally decomposed, at the temperature of 600°: whence it acquired the name of nitrum flammans. The readiest mode of preparing it is, by adding carbonate of ammonia to dilute nitric acid till saturation takes place. If this solution be evaporated in a heat between 70° and 100°, and the evaporation not carried too far, it crystallizes in hexaedral prisms, terminating in very acute pyramids; if the heat rise to 212°, it will afford, on cooling, long fibrous silky crystals: if the evaporation be carried so far, as for the salt to concrete immediately on a glass rod by cooling, it will form a compact mass. According to Mr. Davy, these differ but little from each other, except in the water they contain, their component parts being as follows:

19.8 5.7 duum is pure magnesia. It is disposed to attract moisture from the air, but is much less deliquescent than either of the salts that compose it: and requires eleven parts of water at 60° to dissolve it. Boiling water takes up more, so that it will crystallize by cooling. It consists of 78 parts of nitrate of magnesia and 22 of nitrate of ammonia. From the activity of the nitric acid as a solvent of earths in analyzation, the nitrate of glucine is better known than any other of the salts of this new earth. Its form is either pulverulent, or a tenacious or ductile mass. Its taste is at first saccharine, and afterward astringent. It grows soft by exposure to heat, soon melts, its acid is decomposed into oxygen and azote, and its base alone is left behind. It is very soluble and very deliquescent. Nitrate, or rather supernitrate of alumine crystallizes, though with difficulty, in thin, soft, pliable flakes. It is of an austere and acid taste, and reddens blue vegetable colours. It may be formed by dissolving in diluted nitric acid, with the assistance of heat, fresh precipitated alumine, well washed, but not dried. It is deliquescent, and soluble in a very small portion of water. Alcohol dissolves its own weight. It is easily decomposed by heat. Nitrate of zircone was first discovered by Klaproth, and has since been examined by Guyton-Morveau and Vauquelin. its crystals are small, capillary, silky needles. Its taste is astringent. It is easily decomposed by fire, very soluble in water, and deliquescent. It may be prepared by dissolving zircone in strong nitric acid; but, like the preceding species, the acid is always in excess. Nitrate of ittria may be prepared in a similar manner. Its taste is sweetish, and astringent. It is scarcely to be obtained in crystals; and if it be evaporated by too strong a heat, the salt becomes soft like honey, and on cooling concretes into a stony mass. Exposed to the air it deliquesces. NITRITES. Though these salts are composed of nitrous acid and certain bases, yet the only way of obtaining them is by exposing a nitrate to a pretty strong heat, till a quantity of the oxygen gas is disengaged from it: what remains is a nitrate. These salts have never been minutely examined; but it is inferred, from the experiments that have been made, that they are, in general, deliquescent, very soluble in water, decomposable by heat, and by exposure to the air they are gradually converted into nitrates by absorbing oxygen. NITROGEN. See ATMosphen E.; also GAs. NITROUS acid. It has already been observed, that there is no such thing, properly speaking, as nitrous acid, or the nitric base acidified with a minimum dose of oxygen; but that the nitric acid is capable of absorbing various portions of nitric oxide, with which it parts very readily, so that, when in considerable quantity, it gives it out in the ordinary state of the air, on mixing with which it assumes the appearance of a very red vapour. Hence it was formerly called fuming nitrous acid. It appears, however, to be capable of combining with some at least of the salifiable bases, so as to form a distinct genus of salts, that may be termed nitrites. But these cannot be formed by a direct union of their component parts; being obtainable only by exposing a nitrate to a high temperature, which expels a portion of its oxgen in the state of gas, and leaves the remainder in the state of a nitrite, if the heat be not urged so far, or continued so long, as to effect a complete decomposition of the salt. In this way the nitrates of potash and soda may

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be obtained and perhaps those of barytes, stroatian, lime and magnesia. The nitrites are particularly characterized by be. ing decomposable by all the acids, except the carbonic, even by the nitric acid itself, all of which expel from it nitrous acid. We are little acquainted with any one except that of potash, which attracts moisture from the air, changes blue vegetable colours to green, is sometimes acrid to the taste, and when powdered emits a smell of nitric oxide.

Nitrous oxide. See GAs.

NOBILITY, a quality that ennobles and raises a person possessed of it above the rank of a commoner. The origin of nobility in Europe is by some referred to the Goths; who, after they had seized a part of Europe, rewarded their captains with titles of honour to distinguish them from the common people. In Britain the term nobility is restrained to degrees of dignity above knighthood ; but every where else nobility and gentility are the same. The British nobility consists only of five degrees, viz. that of a duke, marquis, earl or count, viscount, and baron, each of which see under their proper articles. In Britain these titles are only conferred by the King, and that by patent, in virtue of which it becomes hereditary. The privileges of the nobility are very considerable; they are all esteemed the King's hereditary counsellors, and are privileged from all arrests, unless for treason, felony, breach of peace, condemnation in parliament, and contempt of the King. They enjoy their seats in the House of Peers by descent, and no act of parlia. ment can |. without their concurrence: they are the supreme court of judicature, and even in criminal cases give their verdict upon their honour, without being put to their oath. In their absence they are allowed a proxy to vote for them, and in all places of trust are permitted to constitute deputies, by reason of the necessity the law supposes them under of attending the King's person; but no peer is to go out of the kingdom without the King's leave, and when that is granted, he is to return with the King's writ, or forfeit goods and chattels.

NOBLE, a money of account, containing six shillings and eight-pence. The noble was anciently a real coin, struck in the reign of Edward III. and then called the penny of gold; but it was afterwards called a rose noble, from its being stamped with a rose.

NOCTURNAL, something relating to r of the night, in contradistinction to diurmal. | " Noctun NAL arch, in astronomy, the arch of a circle described by the sun, or a star, in the night. | NocturnAL, semi, arch of the sun, is that | portion of a circle he passes over between the lower part of our meridian and the point of the horizon, wherein he arises; or between the point of the horizon, wherein he sets, and the lower part of our meridian. Nocturn AL, or Nocturla BIUM, an instrument chiefly used at sea, to take the altitude or depression of some stars about the pole, in order to find the latitude and hour of the night. Some nocturnals are hemispheres, or planispheres, on the plane of the equinoctial. Those commonly in use among seamen are two; the one adapted to the polar star, and the first to the guards of the little bear; the other to the pole-star, and the pointers of the great bear. This instrument consists of two circular plates applied to each other. The greater, which has a handle to hold the instrument, is about two inches and a half diameter, and is divided into twelve parts, agreeing to the twelve months, and each month subdivided into every fifth | day; and so as that the middle of the handle corresponds to that day of the year wherein the star, here regarded, has the same right ascension with the sun. If the instrument be fitted for two stars, the ... handle is made moveable. The upper left circle is divided into twenty-four equal parts, for the twenty-four hours of the day, and each hour subdivided into quarters. These twenty-four hours are * noted by twenty-four teeth, to be told in the night. Those at the hours twelve are distinguished by their length. In the centre of the two circular plates is ad; justed a long index, moveable upon the upper plate. And the three pieces, viz. the two circles and index, are joined by a rivet, which is pierced through the centre with a hole, through which the star is . . to be observed. “To use the Nocturnal,” turn the upper plate till the long tooth, marked twelve, be against the day of the month on the under plate : then, bringing the instrument near the eye, suspend it by the handle, with the plane nearly parallel to the equinoctial; and viewing the pole. star through the hole of the centre, turn : the index about, till, by the edge coming from the centre, you see the bright star or guard of the little bear (if the instruwoment be fitted to that star): then that

tooth to the upper circle, under the edge of the index, is at the hour of the night on the edge of the hour circle; which may be known without a light, by counting the teeth from the longest, which is for the hour twelve. NODE, in surgery, a tumour arising on the bones, and usually proceeding from some venereal cause; being much the same with what is otherwise called exostosis. NODES, in astronomy, the two points wherein the orbit of a planet intersects the ecliptic, whereof the node, where the planet ascends northwards, above the plane of the ecliptic, is called the ascending node, the northward node, and the head of the Dragon, and is marked thus Q ; the other node, where the planet descends to the south, is called the descending node, the southward node, or the Dragon’s tail, marked thus $3. The line wherein the two circles intersect, is called the line of nodes. It appears from observation, that the line of the nodes of all the planets constantly changes its place, and shifts its situation from east to west, contrary to the order of the signs; and that the line of the moon’s nodes, by a retrograde motion, finishes its circulation in the compass of nineteen years; after which time either of the nodes, having receded from any point of the ecliptic, returns to the same again; and when the moon is in the node, she is also seen in the ecliptic. If the line of nodes were immoveable, that is, if it had no other motion than that whereby it is carried round the sun, it would always look to the same point of the ecliptic, or would keep parallel to itself, as the axis of the earth does. From what has been said, it is evident that the moon can never be observed precisely in the ecliptic but twice in every period, that is, when she enters the nodes. When she is at her greatest distance from the nodes, viz. in the points, she is said to be in her limits. The moon must be in or near one of the nodes, when there is an eclipse of the sun Ol' moon. NOLANA, in botany, a genus of the Pentandria Monogynia class and order. Natural order of Asperifoleae or Luridae. Borragineae, Jussieu. Essential character: corollabell-shaped: style among the germs; seeds five, berried, two-celled. There is but one species, viz. N. protrastra, trailing nolana. NOLLE prosequi, is used where the plaintiff ...is proceed no further in his action, and may be as well before as after a verdict, and is stronger against the plaintiff than a nonsuit, which is only a default in appearance; but this is a voluntary acknowledgement that he has no cause of action. In criminal cases it can only be entered by the Attorney General

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NOLLET, (John ANthony,) in biography, a French ecclesiastic and celebrated natural philosopher in the eighteenth century, was born at Pimprè, in the diocese of Noyon, in the year 1700. His parents, who were persons of reputable character, though of humble fortunes, as they could not make him wealthy, determined to bestow on him the advantages of a good education. With this view they sent him to the college of Clermont in the Beauvoisin, and afterwards to Beauvais, where he laid a good foundation of grammar learning, which encouraged them to send him to Paris, in order to go through a course of philosophy at that university. It was their wish that he should embrace the ecclesiastical profession, and young Nollet adopted without repugnance the choice which they made for him. From a very early age he had shewn a taste for the study of natural philosophy, which had not yet become his ruling passion; he was, therefore, enabled to check himself in a pursuit, which was likely to interfere with the studies more appropriate to his destined character, and gave himself up entirely to the study of scholastic theology. Having completed his academical course, and passed with reputation through the usual examinations, in 1728 he was admitted to deacon’s orders, and soon became a licensed preacher. This new occupation, however, did not wholly divert his attention from the subjects of his early inquiries, and they insensibly claimed more and more of his time. At length his inclination for the sciences became irresistible, and he gave himself up to the study of natural philosophy, with an ardour to which the kind of privation in which he had so long lived gave augmented force. It was now his good fortune to become known to M. du Fay and M. Reaumur, and under their instructions his talents were rapidly developed. By the former he was received as an associate in his electrical researches; and the latter resigned to him his laboratory. He was also received into a Society of Arts, established at Paris under the protection of the Count de Clermont. In the year 1734, he accompanied M. D. du Fay, du Hamel, and de Jussieu, on a visit to England, where he had the honour of being

admitted a foreign member of the Royal Society, and he profited so well of this visit, as to institute a friendly and literary correspondence with some of the most celebrated men in this country. Two years afterwards he made a tour to Hol. land, where he formed an intimate connection with s”Gravesande and Musschenbroek. Upon his return to Paris, he resumed a course of experimental philosophy, which he commenced in 1735, and which he continued to the year 1760. These courses of experimental physics gave rise to the adoption of similar plans in other branches of science, such as chemistry, anatomy, natural history, &c. In the year 1738, the Count de Maurepas prevailed upon Cardinal Fleury to establish a public professorship of experimental philosophy at Paris, and the Abbé Nollet was the first person who received the appointment. During the following year, the Royal Academy of Sciences appointed him adjunct mechanician to that body; and in 1742 he was admitted an associate. In the year 1739, the King of Sardinia being desirous of establishing a professorship of Physics at Turin, gave an invitation to the Abbé Nollet to perform a course of experimental philosophy before the Royal Family, with which he complied. tour to Italy, where he collected some good observations concerning the natural history of the country. In the year 1744, he had the honour of being called to Ver. sailles, to give lessons in natural philosophy to the Dauphin, at which the King and royal family were frequently present, By the excellence and amiableness of his personal character, as well as by his scientific talents, he recommended himself to the confidence of his illustrious pupil, who continued as long as he lived to express the greatest esteem for our philosopher. It is to be lamented that his liberality did not prompt him to better the mediocrity of his tutor’s fortune. In the year 1749, the Abbé Nollet took a second journey into Italy, whence wonderful accounts had been circulated throughout Europe, of the communication of medicinal virtues by electricity, which seemed to be supported by numerous wellattested facts. To examine into these facts, and to be assured of their truth or fallacy was one grand motive with our author in passing the Alps at this time, and in visiting the gentlemen who had published any accounts of those experiments. But though he engaged them to repeat their experiments in his presence, and upon himself, and though he made

From Turin he took a

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