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Oxide of menachine . i. 84 by the jury to the court above, the judges Oxide of iron . . . . . . . 14

14 there give judgment for the party for Oxide of manganese .... 2 whom the verdict is found. All trials at

law, in the civil courts, and at the assizes, 100 are tried by this process, and are called

trials at Nisi Prius.

NISSOLIA, in botany, so named in boNILOMETER, sometimes called Nilo. nour of Guill. Nissole, M. D. of Montpelscope, an instrument used among the an. lier; a genus of the Diadelphia Decancients to measure the height of the water dria class and order. Natural order of in the river Nile, in its periodical over. Papilionaceæ, or Leguminosz. Essential flowings. It was first set ap, it has been character: calyx five-toothed; capsule asserted, by Joseph, during his govern one-seeded, ending in a ligulate wing. ment in Egypt. The measure of it was There are two species, viz. N. arborea, sixteen cubits, this being the height to tree nissolia ; and N. fruticosa, sbrubby which it must rise in order to insure the nissolia ; both natives of Carthagena, in fruitfulness of the country.

woods and coppices. NINTH, in music, an interval, contain NITIDULA, in natural history, a genus ing an octave and a tone ; also a name of insects of the order of Coleoptera. An. given to the chord, consisting of a com. tennæ clavate, the club solid, and nearly mon chord, with the eighth advanced one orbicular; shells margined; head pronote.

minent; thorax fattened, margined. NIPA, in botany, a genus of the Appen There are about forty-two species enudix Palmæ class. Natural order of Palmæ merated by Gmelin, separated into secor Palms. Essential character: male, tions according to the form of the lip. A. spathe ; corolla six-petalled: female, Lip cylindrical B. Lip square. N. bispathe : corolla none; drupes angular. pustulata is oval, black; shells with a There is but one species, viz. N. fruticans, red dot. It inhabits Europe and Amethe young palm, is without the trunk; rica, and lives on carcases, meat, bacon, but in the adult state, it is some feet in &c. height; leaves pinnate; pinnastriated, NITRARIA, in botany, a genus of the margined and smooth; flowers male and Dodecandria Monogynia class and order. female on the same palm; but distinct on Natural order of Ficoideæ, Jussieu. Esdifferent peduncles : males several, late. sential character: calyx five-cleft; corol. ral, inferior, on dichotomous peduncles, la five-petalled, with the petals arched at in spikes: females terminating, aggregate top : stamina fifteen or more ; drupe one. in a globular head, sessile. It is a native · seeded. There is but one species, viz. of Java and other islands in the East In. N.schoberi. Thick-leaved Vitraria. dies, where the leaves are used for cover. NITRATES, in chemistry, salts formed ing houses and making mats. The fruit is of the nitric acid, and alkalies, earths, eaten both raw and preserved.

&c. They possess the following proper: NIPPLES, in anatomy. See MAMMARY ties : soluble in water, and capable of

crystallizing by cooling; when heated to NISI PRIUS, a commission directed to redness with combustible bodies, a vio. the judges of assize, empowering them lent combustion and detonation is proto try all questions of fact issuing out of duced : sulphuric acid disengages from the courts at Westminster, that are then them fumes which have the odour of ni. ready for trial by jury. The original of tric acid : when heated with muriatic which name is this : all causes commenced acid, oxymuriatic acid is driven off: they in the courts of Westminster-hall are, by are decomposed by heat, and yield at first course of the courts, appointed to be tried oxygen gas. There are twelve nitrates, on a day fixed in some Easter or Michael. of which the most important is the ni. mas term, by a jury returned from the trate of potash, or nitre : this salt, county where the cause of action arises; known also by the name of salt.petre, is but with this proviso, nisi prius justiciarii produced naturally in considerable quanad assisas capiendas venerint : that is, un- tities, particularly in Egypt, and has been less, before the day prefixed, the judges known from time immemorial. Roger of assize came into the county in ques. Bacon mentions it under the name of nition, which they always do in the vaca. tre, in the thirteenth century. The imtion preceding each Easter and Michael. portance of this substance for the purmas term, and there try the cause ; and poses of war has led chemists to seek then upon the return of the verdict given the best means of preparing it, especial


ly as nature has not laid up large maga. nates more violently with combustible bo. zines of it, as she has of other salts. It is dies than any of the other nitrates. When now ascertained, that nothing more is mixed with one-third part of its weight of necessary for the production of nitre than charcoal, and thrown into a red-hot cru. a basis of lime, heat, and an open, but cible, or when charcoal is thrown into not too free, communication with dry at red-hot nitre, detonation takes place, and mospheric air. When these circum- one of the most brilliant combustions that stances combine, the acid is first formed, can be exhibited. The residuum is carand afterwards the alkali. See Nitric bonate of potash. A still more violent acid.

detonation takes place, if phosphorus is NITRE. See NITRATES. Nitre is used instead of charcoal. Nitre oxydizes found abundantly on the surface of the all the metals at a red beat. The compo. earth, in India, South America, South sition of nitre, according to Kirwan, is Africa, and even in some parts of Spain. In Germany and France it is obtained by Acid means of artificial nitre-beds. These Potash

51.8 consist of the refuse of animal and vege. Water

4.2 table bodies, undergoing putrefaction, mixed with calcareous and other earths.

100.0 It has been ascertained, that if oxygen gas be presented to azote at the instant of its disengagement, nitric acid is formed. Nitre furnishes all the nitric acid in all This seems to explain the origin of the its states, employed either by chemists or acid in these beds. The azote, disen- artists: it is obtained by decomposing it gaged from these putrefying animal sub. by means of the sulphuric acid. When stances, combines with the oxygen of the burnt with tartar, it yields a pure carbonair. The potash is probably furnished, ate of potash. In the assaying of various partly at least, by the vegetables and the ores it is indispensable, and is equally nesoil. The nitre is extracted from these cessary in the analysis of many vegetable beds, by lixiviating the earthy matters and animal substances. But one of the with water. This water, when sufficient most important compounds, formed by ly impregnated, is evaporated, and a means of nitre, is gunpowder, which has brown-coloured salt obtained, known by completely changed ihe modern art of the name of crude nitre. It consists of war. The discoverer of this compound, nitre, common salt, nitrate of lime, and and the person who first thought of apvarious other salts. The foreign salts are plying it to the purposes of war, are uneither separated by repeated crystalliza- known. It is certain, however, that it tions, or by washing the salt repeatedly was used in the fourteenth century.with small quantities of water: for the From certain archives, quoted by Wiegforeign salts being more soluble, are leb, it appears that cannons were employ. taken up first. Nitre, when slowly eva. ed in Germany before the year 1372. No porated, is obtained in six-sided prisms, traces of it can be found in any European terminated by six-sided pyramids; but author, previous to the thirteenth centufor most purposes it is preferred in an ry; but it seems to have been known to irregular mass, because in that state it the Chinese long before that period. contains less water. The specific gravity There is reason to believe that cannons of nitre, as ascertained by Dr. Watson, is were used in the battle of Cressy, which 1.9. Its taste is sharp, bitterish, and was fought in 1346. They seem even to cooling. It is very brittle. It is soluble have been used three years earlier at the in seven times its weight of water, at the siege of Algesiras; but before this time, temperature of 60°; and in rather less they must have been known in Germany, than its own weight of boiling water, as there is a piece of ordnance at Amberg, When exposed to a strong heat it melts, on which is inscribed the year 1303. Ro. and congeals by cooling into an opaque ger Bacon, who died in 1292, knew the mass, which has been called mineral crys- properties of gunpowder : but it does tal. Whenever it melts, it begins to dis- not follow that he was acquainted with its engage oxygen; and, by keeping it in a application to fire-arms. See GunPow. red heat, about a third of its weight of DER. When three parts of nitre, two that gas may be obtained: towards the parts of potash, and one part of sulphur, end of the process azotic gas is disengag. all previously well dried, are mixed togeed. If the heat be continued long enough ther in a warm mortar, the resulting comthe salt is completely decomposed, and pound is known by the name of fulminatpure potash remains behind. It deto. ing powder. If a little of this powder be

put into an iron spoon, and placed upon from which it is expelled by sulphuric burning coals, or held above the flame of acid. a candle, it gradually blackens, and Four parts of pure nitrate of potash, at last melts. At that instant it explodes coarsely powdered, are to be put into a with a very violent report, and a strong glass retort, and three parts of concenimpression is made upon the bottom of trated sulphuric acid cautiously added, the spoon, as if it had been pressed taking care to avoid the fumes that arise, down very violently. This sudden and which is best done by standing in a curviolent combustion is occasioned by the rent of air, to convey them up the chimrapid action of the sulphur on the nitre. ney. Join to the retort a tubulated reBy the application of the heat, the sul. ceiver of large capacity, with an adopter phur and potash form a sulphuret, which interposed, and lute the junctures with a is combustible at a lower heat probably mixture of pipe-clay, sifted sand and cut than even sulpbar. Sulphurated hydro. tow. In the tubulure fix with fat lute a gen gas, azotic gas, and perhaps also sul- glass tube, terminating in another large phurous acid gas, are disengaged almost receiver, in which is a small quantity of instantaneously. It is to the sudden ac. water ; and if you wish to collect the tion of these on the surrounding air that gaseous products, let a bent glass tube the report is to be ascribed. Its loudness from this receiver communicate with a evidently depends upon the combustion pneumatic trough. Apply heat to the reof the whole powder at the same instant, ceiver by means of a sand bath. The first which is secured by the previous fusion product that passes into the receiver is that it undergoes; whereas the grains of generally red and fuming; but the apgunpowder burn in succession. A mis pearances gradually diminish, till the acid ture of equal parts of tartar and nitre, comes over pale, and even colourless, if deflagrated in a crucible, is known by the the materials used were clean. After name of white flux. It is merely a mix- this it again becomes more and more red ture of carbonate of potash, with some and fuming, till the end of the operation; pure potash. When two parts of tartar, and the whole mingled together will be and one of nitre, are deflagrated in this of a yellow or orange colour. manner, the residuum is called black flux, In the large way, and for the purposes from its colour. It is merely a mixture of of the arts, extremely thick cast iron or charcoal and carbonate of potash.

earthen retorts are usually employed, to Nitre is much used in medicine, in fe. which an earthen head is adapted, and vers as a cooling remedy, and as a diu- connected with a range of proper conretic in urinary affections. It is employ. densers. The strength of the acid too is ed also in many arts, as in dyeing ; and in varied, by putting more or less water in domestic economy, for the preservation the receivers. The nitric acid thus made of animal substances used for food. To generally contains sulphuric acid, and also these substances it imparts a red colour. muriatic, from the impurity of the nitrate See NITROUS acid; also GUNPOWDER. employed. If the former, a solution of

NITRIC acid. The two principal con- nitrate of barytes will occasion a white stituent parts of our atmosphere, when in precipitate: if the latter, nitrate of silver certain proportions, are capable, under will render it milky. The sulphuric acid particular circumstances, of combining may be separated by a second distillation chemically, into one of the most powerful from very pure nitre, equal in weight to acids, the nitric, which consists, according an eighth of that originally employed; or to Mr. Davy, of 70.5 of oxygen, and 29.5 by precipitating with nitrate of barytes, of azote, or nitrogen. If these gases be decanting the clear liquid, and distilling mixed in this proportion in a glass tube, it. The muriatic acid may be separated about a line in diameter, over mercury, by proceeding in the same way with ni. and a series of electric shocks be passed trate of silver, or with litharge, decanting through them for some hours, they will the clear liquor, and redistilling it, leav. form nitric acid; or, if a solution of pot- ing an eighth or tenth part in the retort. ash be present with them, nitrate of pot. The acid for the last process should be ash will be obtained. The constitution of condensed as much as possible, and the this acid may be further proved, analyti. redistillation conducted very slowly; and cally, by driving it through a red-hot por- if it be stopped, when half is come over, celain tube, as thus it will be decomposed beautiful crystals of muriate of lead will into oxygen and nitrogen gases. For all be obtained on cooling the remainder, if practical purposes, however, the nitric litharge be used, as M. Steinacher informs acid is obtained from nitrate of potash, us; who also adds, that the vessels should


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be made to fit tight by grinding, as any not mention the specific gravity of this lute is liable to contaminate the product. acid: be only says, that it was prepared

As this acid still holds in solution more by first expelling the water of crystallizaor less nitrous gas, it is not, in fact, nitric tion from nitre by heat, and then decomacid, but a kind of nitrous: it is therefore posing this nitre by means of strong sulnecessary to put it into a retort, to which phuric acid. a receiver is added, the two vessels not The nitric acid is of considerable use being luted, but merely joined by paper; in the arts. It is employed for etching and to apply a very gentle heat for several on copper, as a solvent of tin, to form hours, changing the receiver as soon as it with that metal a mordant for some of the is filled with red vapours. The nitrous finest dies; in inetallurgy and assaying: gas will thus be expelled, and the nitric in various chemical processes, on account acid will remain in the retort, as limpid of the facility with which it parts with and colourless as water. It should be oxygen and dissolves metals ; in medikept in a bottle secluded from the light, cine as a tonic, and as a substitute for otherwise it will lose part of its oxygen. mercurial preparations in sypbilis and af

The strongest acid that Mr. Kirwan fections of the liver; as also in the form could procure at 60° was 1.5543, which of vapour, to destroy contagion. For the by his calculation contained .7354 of real purposes of the arts it is commonly used acid; but Rouelle professes to have ob. in a diluted state, and contaminated with tained it of 1.583. It is observable, that, the sulphuric and muriatic acids, by the on comparing the tables of Kirwan and name of aqua fortis. This is generally Davy, the aeriförm acid appears to con- prepared by mixing common nitre with an tain a considerable portion of water inore equal weight of sulphate of iron, and half than that which is combined with soda to its weight of the same sulphate calcined, form the nitrate.

and distilling the inixture : or by mixing Nitric acid should be of the specific nitre with twice its weight of dry powgravity of 1.5, or a little more, and co- dered clay, and distilling in a reverberalourless. It boils at 248°, and may be dis- tory furnace. Two kinds are found in the tilled without any essential alteration. shops, one called double aqua fortis, Exposed to the air, it absorbs moisture. which is about half the strength of nitric If two parts be suddenly diluted with one acid ; the other simply aqua fortis, which of water, the temperature will rise to is half the strength of the double. about 112° ; but the addition of more wa. A compound made by mixing two parts ter to this diluted acid will lower its tem of the nitric acid with one of muriatic, perature. It retains its oxygen with little known formerly by the name of aqua reforce, so that it is decomposed by all com- gia, and now by that of nitro-muriatic bustible bodies. Brought into contact acid, has the property of dissolving gold with hydrogen gas at a high temperature, and platina. On mixing the two acids, a violent detonation ensues, so that this heat is given out, an effervescence takes must not be done without great caution. place, oxygenated muriatic acid gas is It intlames volatile oils, such as those of evolved, and the mixture acquires an turpentine and cloves, when suddenly orange colour. This is likewise made by poured on them : but to perform this ex. adding gradually to an ounce of powderperiment with safety, the acid must be ed muriate of ammonia, four ounces of poured out of a bottle tied to the end of double aqua fortis, and keeping the mixà long stick, otherwise the operator's ture in a sand-heat till the salt is dissolved; face and eyes will be greatly endangered taking care to avoid the fumes, as the vesIf it be poured on perfectly dry charcoal sel must be left open: or by distilling powder, it excites combustion, with the nitric acid with an equal weight, or rather emission of copious fumes. By boiling it more, of common salt. with sulphur it is decomposed, and its W ith the different bases the nitric acid oxygen, uniting with the sulphur, forms forms nitrates. sulphuric acid. Chemists in general agree, The nitrate of barytes, when perfectly that it acts very powerfully on almost all pure, is in regular octaedral crystals, the metals : But Baume has asserted, that though it is sometimes obtained in small it will not dissolve tin; and Dr. Wood. shining scales. It may be prepared by house of Pennsylvania affirms, that in a uniting barytes directly with nitric acid, highly concentrated and pure state it acts or by decomposing the carbonate of sul. not at all on silver, copper, or tin, though phuret of barytes with this acid. Exwith the addition of a little water its ac. posed to heat it decrepitates, and at length tion on them is very powerful. He does gives out its acid, wbich is decomposed; but if the heat be urged too far, the ba. of each, and a quantity of straw within rytes is apt to vitrify with the earth of the to prevent its being stopped up. Into crucible. It is soluble in 12 parts of cold, these the matter is put, together with and 3 or 4 of boiling water. It is said to wood-ashes, either strewed at top, or addexist in some mineral waters.

ed during the filling. Boiling water is The nitrate of potash, is the salt well then poured on, and suffered to stand for known by the name of nitre, or salt. some time; after which it is drawn off, petre. It is found ready formed in the and other water added in the same manEast Indies, in Spain, in the kingdom of ner, as long an any saline matter can be Naples, and elsewhere, in considerable thus extracted. The weak brine is heatquantities; but nitrate of lime is still ed, and passed through other tubs, until more abundant. Far the greater part of it becomes of considerable strength. It the nitrate made use of is produced by a is then carried to the boiler, and contains combination of circumstances which tend nitre and other salts; the chief of which to compose and condense nitric acid. This is common culinary salt, and sometimes acid appears to be produced in all situa. muriate of magnesia. tions, where animal matters are com. It is the property of nitre to be much pletely decomposed with access of air, more soluble in hot than cold water; but and of proper substances with which it common salt is very nearly as soluble in can readily combine. Grounds frequent cold as in hot water. Whenever, there. ly trodden by cattle, and impregnated fore, the evaporation is carried by boiling with their excrements, or the walls of in- to a certain point, much of the common habited places where putrid animal va salt will fall to the bottom, for want of pours abound, such as slaughter-houses, water to hold it in solution, though the drains, or the like, afford nitre by long nitre will remain suspended by virtue of exposure to the air. Artificial nitre beds the heat. The common salt thus sepaare made, by an attention to the circum. rated is taken out with a perforated lastances in which this salt is produced by dle, and a small quantity of the fluid is nature. Dry ditches are dug, and cover cooled, from time to time, that its coned with sheds, open at the sides, to keep centration may be known by the nitre off' the rain : these are filled with animal which chrystallizes in it. When the fluid is substances, such as dung, or other excre- sufficiently evaporated, it is taken out ments, with the remains of vegetables, and cooled, and great part of the nitre and old mortar, or other loose calcareous separates in crystal; while the remaining earth; this substance being found to be common salt continues dissolved, bethe best and most convenient receptacle cause equally soluble in cold and in hot for the acid to combine with. Occasional water. Subsequent evaporation of the watering, and turning up from time to residue will separate more nitre in the time, are necessary, to accelerate the same manner. process, and increase the surfaces to This nitre, which is called nitre of the which the air may apply; but too much first boiling, contains some common salt; moisture is hurtful. When a certain por from which it may be purified by solution tion of nitrate is formed, the process ap- in a small quantity of water, and subse. pears to go on more quickly : but a cer- quent evaporation ; for the crystals thus tain quantity stops it altogether, and after obtained are much less contaminated with this cessation, the materials will go on to common salt than before ; because the furnish more, if what is formed be ex- proportion of water is so much larger tracted by lixiviation. After a success with respect to the small quantity consion of many months, more or less, ac- tained by the nitre, that very little of it cording to the management of the opera- will crystallize. For nice purposes, the tion, in which the action of a regular solution and crystallization of nitre are recurrent of fresh air is of the greatest peated four times. The crystals of nitre importance, nitre is found in the mass. are usually of the form of six-sided flat. If the beds contained much vegetable tened prisms, with diedral summits. Its matter, a considerable portion of the taste is penetrating ; but the cold pronitrous salt will be common saltpetre ; duced, by placing the salt to dissolve in but, if otherwise, the acid will, for the the mouth, is such as to predominate over most part, be combined with the calcare. the real taste at first. Seven parts of ous earth.

water dissolve two of nitre, at the temTo extract the saltpetre from the mass perature of sixty degrees; but boiling of earthy matter, a number of large casks water dissolves its own weight. One are prepared, with a cock at the bottom hundred parts of alcohol, at a beat of one

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