Obrazy na stronie

The babe that milks me:

Siberian wares; but it has also an as I would, while it was smiling in my face, commerce in salt, corn, and provisions : Have plucked my nipple from his boneless gums. is a great depôt of salt-works; both e

Shakspeare. of the adjoining province of Perm. The As his foe, went then suffised away, 'Thoas Ætolius threw a dart, that did his pile convey and warehouses are more substantial. The

ling-houses are generally of wood, but the Above his nipple, through his lungs.

In creatures that nourish their young with milk, has a seminary and high school; martie are adapted the nipples of the breast to the mouth of thread and ropes, with breweries and es. and organs of suction. Ray on the Creation. ries. Since 1816 the large fair of Malar

In most other birds there is only one gland, in been held here. Population 10,000. 2: which are divers little cells ending in two or three E. N. E. of Moscow, and 540 E. S. Edhe larger cells, lying under the nipple of the oil bag. burg. Derham's Physico-Theology.

NISHAPOUR, an ancient, and on : NIPPLE-WORT, in botany. See Lapsana. brated city of Persia, in Korassan, ktor i •

NISAN, a month of the Hebrew kalendar, an- times of Alexarıder the Great, whose state swering to our March, and which sometimes here until it was overthrown by the Aras takes from February to April, according to the disputed with Meru Shah Jehan the chara course of the moon. It was the first month of being the capital of the Seljukian dynasty

, it the sacred year, after the Exodus from Egypt its reign over Persia ; and, about the (Exod. xii. 2), and the seventh of the civil year. the twelfth century, was taken by the Is. By Moses it is called Abib. The name Nisan and so completely ruined, that, when the r., was used only from the time of Ezra, and the re- tants returned, they could not distinger turn from the captivity of Babylon. On the own houses. Hakani, the Persian poete 1st of this month the Jews fasted for the death period, has affectingly described the back of Aaron's sons. (Lev. X. 1, 2, 3). On the 10th condition to which this unhappy placere was a fast for Miriam the sister of Moses; and duced. It never recovered from this bar every one provided himself with a lamb for the now contains above 15,000 inhabitası passover. On this day the Israelites passed over ruins are said to cover a circuit of tra Jordan under the conduct of Joshua (iv. 19). miles. The most delicious fruits are pozi On the 14th, in the evening, they sacrificed the in the neighbourhood. Thirty miles ... paschal lamb; and on the 15th was held the so- Mesched, and 230 north-east of Herat

. lemn passover. (Exod. xii. 18, &c.) On the NISI Prius, n. s. In law, a jedak 16th they offered the sheaf of the ears of barley which lieth in case where the inquest is as the first-fruits of the harvest. (Levit. xxiii. 9, and returned before the justices of the &c.) The 21st was the octave of the passover, the one party or the other making pets which was solemnised with particular ceremonies. have this writ for the ease of the country

. The 26th was a fast in memory of the death of directed to the sheriff, commanding Joshua. On this day they began their prayers to cause the men impanelled to come bei obtain the rains of the spring. On the 29th they justices in the same county, for the deri commemorated the fall of the walls of Jericho. of the cause there, except it be so diffico

NISCHNEI-NOVGOROD, or NISH ECOROD, need great deliberation : in which case ! : an extensive government of European Russia, again to the bank. It is so called from a situated in the centre of the empire, to the east of words of the writ nisi apud talem locus that of Vladimir. It lies between 41° 45' and venerint; whereby it appeareth that 46° 15' E. long., and 54o and 57° N. lat., and has assizes and justices of nisi prius differ

. an area of 20,400 square miles. Its surface is justices of nisi prius must be one of thet diversified only by slight undulations, and it has whom the cause is depending in the benc: a productive soil, and temperate climate. Corn, some other good men of the county as hemp, and cattle, are the great agricultural ob- to him.- Cowell. jects; fishing in the rivers and lakes, and the NISIBIS, in ancient geography, a TEmanufactures, employ great numbers of the po- cient, noble, and strong city of Mesopus

. pulation. Leather, soap, tallow, and canvas, are Mygdonia towards the Tigris, from what not neglected. This province is traversed by the distant two days' journey. Some ascrizes Vetluga, the Sura, the Wolga, and the Oka; the gin to Nimrod, and suppose it to be two last affording a direct communication by wa- of Moses. It was built by a colony oikein ter

, both with Moscow and St. Petersburg. nians, who call it Antiochia of Mygdon-li This government is divided into eleven circles, tarch. Strabo says it was situated at the *** and contains 1,000,000 inhabitants.

Mount Masius. It was the Roman liekasi Nischner-NOVGOROD, i. e. Lower-Novgorod, against the Parthians and Persians. It seems a large commercial town of European Russia, the three memorable sieges against the poss see of an archbishop, and the capital of the Sapor, A. D. 338, 346, and 350 ; but the ear" government of this name, is situated at the con- Jovianus, by an ignominious peace, fluence of the Oka and Wolga. The position at it up to the Persians, A. D. 363. the junction of two large navigable rivers has NISROCH, a god of the Assyrians. caused its trade to be cultivated by a greater por- cherib was killed by two of his sons, whileo tion of the inhabitants than any other town of ing his adoration to this god. (2 Kings Izt Russia, so that it has been called the inland bar- The septuagint calls him Mesrach ; Jest bour of the empire. The chief branch of traffic is calls him Araskes. The Hebrew of Tobit, that which it carries on with St. Petersburg in lished by Munster, calls him Dajon.



think the word signifies a dove ; others under- raised strong fortifications on the side of the stand by it an eagle, which has given occasion river, and caused a vault to be made under it, to an opinion, that Jupiter Belus, from whom the leading from the old palace to the new, twelve Assyrian kings pretended to be derived, was feet high, and fifteen wide. She likewise built a worshipped by them under the form of an eagle, bridge across the Euphrates, and accomplished and called Nisroch.

several other works, which were afterwards asNISSOLIA, in botany, a genus of the decan- cribed to Nebuchadnezzar. Philostratus, in dedria order, and diadelphia class of plants; natural scribing this bridge, tells us, that it was built by order thirty-second, papilionaceæ : Cal. quinque- a queen, who was a native of Media; whence dentate : CAPS. monospermons, and terminated we may conclude Nitocris to have been by birth by a ligulated wing.

a Mede. NISUS, the son of Ilyrtacus, a young Trojan, NITRARIA, in botany, a genus of the monowho accompanied Æneas to Italy. He was gynia order, and dodecandria class of plants : united in the closest friendship with Euryalus. cor. pentapetalous, with the petals arched at the They signalised themselves in the war with the top: CAL. quinquefid; the stamina fifteen; the Rutulians; went into their camp in the night fruit a monospermous plum. and committed great slaughter; but, returning NITRE,

Fr. nitre ; Lat. nitrum. The victorious, were perceived and killed by the Ru- Nitrous, adj. vulgar name of the nitrate of tulians. Their friendship became proverbial. NITRY. potash. See Nitric Acid.

Nisus, in fabulous history, a king of Megara, Nitrous and nitry signify impregnated with, or son of Mars, or of Pandion, whose life and suc- consisting of, nitre. cess depended on a yellow lock of bis hair not Earth and water, mingled by the heat of the sun, being cut. Minos, king of Crete, besieged Me- gather nitrous fatness more than either of them have gara. Scylla the daughter of Nisus, being in severally. love with Minos, cut off the fatal lock while her

Some tumultuous cloud,

Instinct with fire and nitre, hurried him. Milton. father was asleep. Megara was taken ; Minos despised the parricide, who threw herself in de- Some steep their seed, and some in cauldrons boil,

With vigorous nitre and with lees of oil. Dryden. spair into the sea, and was changed into a lark,

He to quench his draught so much inclined, while Nisus was metamorphosed into a hawk.

May snowy fields and nitrous pastures find, Hence the poets traced the antipathy of these Meet stores of cold so greedily pursued, birds.

And be refreshed with never-wasting food. NIT, n. s.

Sax. þnitu. The egg of NITTY, adj. a louse, or small animal: nitty, Winter my theme confines; whose nitry wind NITTILY, adv. J abounding in nits.

Shall crust the slabby mire, and kennels bind. Gay. One Bell was put to death at Tyburn for moving NITRE. See CHEMISTRY and Nitric Acid. a new rebellion ; he was a man nittily needy, and NITRIA, a famous desert of Egypt, thirtytherefore adventurous.

Hayward. The whame, or burrel-fly, is vexatious to horses Mediterranean, east by the Nile, south by the

seven miles long, bounded on the north by the in summer, not by stinging them, but only by their desert of Seta, and west by St. Hilarion. It had bombylious noise, or tickling them in sticking their formerly a great number of monasteries ; now nits, or eggs, on the hair. NITENCY, n. s.

reduced to four. Its name is derived from a salt Lat. nitentia, or nitor. lake, from which is obtained the Natron of the Lustre ; brightness: also endeavour to spring ancients. or to expand, as light does.

NITRIC ACID, in chemistry, one of the most The atoms of fire accelerate the motion of these powerful acids known, is formed by a combinaendeavour outward, will be augmented : that is, tion of the two constituent elements of the atmothose zones will have a strong nitency to fly wider spheric air, viz. nitrogen and oxygen, in a pecuopen.


liar proportion to each other. If these gases be We restore old pieces of dirty gold to a clean and mixed, in the proportion of 70-5 oxygen to 29.5 nitid yellow, by putting them into fire and aqua nitrogen, in a glass tube about a line in diamefortis, which take off the adventitious filth.

ter, and a series of electric shocks be passed

Boyle on Colours. through them for some hours, uitric acid will be NITHISDALE, NITHSDALE, or NIDDISDALE, formed; or, if a solution of potash be present a large mountainous division of Dumfrieshire, with them, nitrate of potash will be obtained. lying west of Annandale, so named from the For practical purposes it is, however, best obNith. This country was formerly shaded with tained from the nitrate of potash, by means of noble forests, which are now destroyed. At pre- sulphuric acid. sent nothing can be more naked, wild, and Three parts of pure nitre, coarsely powdered, savage; yet it yields lead and silver. The moun- are to be put into a glass retort, and two parts of tains are covered with sheep and black cattle. strong sulphuric acid cautiously added. Join

NITOCRIS, the wife of Evil-Merodach, and to the retort a tubulated receiver of large capamother of Belshazzar, king of Babylon, was a city, with an adopter interposed, and lute the woman of extraordinary abilities. After the junctures with glazier's putty. In the tubulure death of Evil-Merodach she took the burden of fix a glass tube, terminating in another very large all public affairs upon herself; and, while her receiver, in which is a small quantity of water. son followed his pleasures, did all that could be Apply heat to the retort by means of a sand bath. done by human prudence to sustain the tottering The first product that passes into the receiver is empire. She perfected the works which Nebu- generally red and fuming; but the appearchadnezzar had begun for the defence of Babylon; ances gradually diminish, till the acid comes




over pale, and even colorless, if the mate- to ascertain its strength, or the quantity rials used were clean. After this it again be- acid contained in it. Mr. Kirwan si comes more and more red and fuming, till the that the nitrate of soda contained the per end of the operation; and the whole mingled undiluted with water, and thus caleta together will be of a yellow or orange color. strength from the quantity requisite to !"

Empty the receiver, and again replace it. a given portion of soda. Sir H. Dany Then introduce by a small funnel, very cau- cently took the acid in the form of a tiously, one part of boiling water in a slender standard, and found how much of these stream, and continue the distillation. A small tained in an acid of a given specific to quantity of a weaker acid will thus be obtained, the liquid state. See CHEMISTRY, Indet which can be kept apart. The first will have a The following is a Table of Nitric Aci" specific gravity of about 1:500, if the heat have in Dr. Ure's valuable Dictionary of Cheza been properly regulated, and if the receiver was as the result of his own experiments :refrigerated by cold water or ice. Acid of that density, amounting to two-thirds of the weight

Liq. of the nitre, may thus be procured. But com

Specific Acid Dry acid Specific Acid Dr monly the heat is raised too high, whence more

Gravity in in 100. Gravity. in in or less of the acid is decomposed, and its pro

100. portion of water, uniting to the remainder, reduces its strength. It is not profitable to use a

1:5000 100 79.700 1-2947 50, .. smaller proportion of sulphuric acid, when a 1.4980 99 78.9031.2887 49 concentrated nitric is required. But when only

1.4960 98 78.106 1.2826 48 a dilute acid, called in commerce aquafortis, is 1.4940 97 77.309 1.2765 47 11 required, then less sulphuric acid will suffice,

1.4910 96 76-512 1.2705 4613 provided a portion of water be added. 100

1.4880 95 75.715 1.2644 45 parts of good nitre, sixty of strong sulphuric acid, 1.4850 94 74:918 1.2583 44 and twenty of water, form economical proportions. 1.4820 93 74.121 1.2523 43 In the large way, and for the purposes of the

1.4790 92 73.324 1.2462 421 arts, extremely thick cast-iron or earthen retorts

1:4760 91 72.527 1.2402 41 are employed, to which an earthen head is

1.4730 90 71-730 1.2341 40 adapted, and connected with a range of proper 1.4700 89 70-933 1.2277 39 condensers. The strength of the acid too is va- 1.4670 88 70.136 1.2212 38 ried, by putting more or less water in the re

1.4640 87 69.339 1.2148 37 ceivers. The nitric acid thus made generally

1.4600 86 68.542

1 2084 36 contains sulphuric acid, and also muriatic, from

1.457085 67.745

1.2019 35 the impurity of the nitrate employed. If the

1.4530 84 66.948 1.1958 34 former a solution of nitrate of barytes will occa

1.4500 83 66.155 1:1895 33 sion a white precipitate; if the laiter, nitrate of

1.4460 82 65.354 1.1833 32 silver will render it milky. The sulphuric acid

1:4424 81 64.557 1.1770 31 may be separated by a second distillation from

1.4385 80 63.760 1.1709 30 very pure nitre, equal in weight to an eighth of

1.4346 79 62.963 1.1648 29 that originally employed; or by precipitating 1.430678 62 1661.1587 28 with nitrate of barytes, decanting the clear liquid, 1.4269 77 61.369 1.1526 27 and distilling it. The muriatic acid may be se- 1.4228 76 60-572 1:1465 / 26 parated by proceeding in the same way with

1.4189 75 59.775

1.1403 25 nitrate of silver, or with litharge, decanting the 1:4147 | 74 58.978

1.1345 24 clear liquid, and redistilling it, leaving an eighth 1.4107 73 58.181 1.1286 23 or tenth part in the retort.

1.4065 72 57.384 1.1227 22 The vessels should be made to fit tight by

1.4023 71 56.587 1.1 168 21 1 grinding, as any lute is liable to contaminate the

1.3978 70 55.790

1:1109 i 20' product.

1.3945 69 54.993 1•1051 1953 As this acid still holds in solution more or less

1.3882 68 54:196 nitrous gas, it is not in fact nitric acid, but a

1.3833 67 53.399

1.0935 17 kind of nitrous; it is therefore necessary to put 1.3783 66 52.602 it into a retort, to which a receiver is added, the

1.3732 65 51.805 1.0821 / 15 116 two vessels not being luted, and to apply a very 1.3681 64 51.068 1.0764 14 111 gentle heat for several hours, changing the re

1.3630 63 50.211

1.0708 131 ceiver as soon as it is filled with red vapors. 1.3579 62 49:414 1.0651 12 from The nitrous gas will thus be expelled, and the 1.3529 61 48.617 1.0595 11 nitric acid will remain in the retort as limpid 1.3477 60 47.820 1.0540 10 and colorless as water. It should be kept in a 1.3427 59 47:023 1.0485 bottle secluded from the light, otherwise it will 1.3376 58 46.226 1.0430 lose part of its oxygen.

1.3323 57

45.429 1.0375 7 51 What remains in the retort is a bisulphate of 1.3270 56 44.632 1.0320

1.3216 55 43.835 1.0267 expelled by a pretty strong heat, and the resi

1.3163 54 43 038 1.0212 duum, being dissolved and crystallised, will be 1.3110 53 42.241 sulphate of potash.

1.0106 As nitric acid in a fluid state is always mixed 1.3001 51 40:647 1.0053 1 0 with water, different attempts have been made

1.3056 52 41.444

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1.0993 181

1.0878 16

8 69

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4 1.0159 31


This acid is eminently corrosive, sour, and is likewise made by adding gradually to an ounce acrid, whence its old name of aquafortis, now of powdered muriate of ammonia four ounces of commonly applied to the yellow fuming nitrous double aquafortis, and keeping the mixture in a acid. If introduced into the stomach it proves sand heat till the salt is dissolved; taking care to a deadly poison, and destroys the skin when in a avoid the fumes, as the vessel must be left open; concentrated state. It is often contaminated, or by distilling nitric acid with an equal weight, through negligence or fraud in the manufacturer, or rather more, of common salt. with sulphuric and muriatic acids. Nitrate of

On this subject we are indebted to Sir H. lead detects both, or nitrate of barytes may be Davy for some excellent observations, published employed to determine the quantity of sulphuric by him in the first volume of the Journal of acid, and nitrate of silver that of the muriatic. Science. If strong ritrous acid, saturated with The latter proceeds from the crude nitre usually nitrous gas, be mixed with a saturated solution containing a quantity of common salt.

of muriatic acid gas, no other effect is produced When it is passed through a red-hot porcelain than might be expected from the action of nitrous tube, it is resolved into oxygen and nitro- acid of the same strength on an equal quantity gen, in the proportion above stated. It retains of water; and the mixed acid so formed has no ils oxygen with little force, so that it is decom- power of action on gold or platina. Again, if posed by all combustible bodies. Brought into muriatic acid gas, and nitrous gas, in equal vocontact with hydrogen gas at a high temperature lumes, he mixed together over mercury, and half a violent detovation ensues; so that this must a volume of oxygen he added, the immediate not be done without great caution. It inflames condensation will be no more than might be exessential oils, as those of turpentine and cloves, pected from the formation of nitrous acid gas. when suddenly poured on them; but, to perform And when this is decomposed, or absorbed by the this experiment with safety, the acid must be mercury, the muriatic acid gas is found unaltered, poured out of a bottle tied to the end of a long mixed with a certain portion of nitrous gas. stick, otherwise the operator's face and eyes will It appears then that nitrous acid, and muriatic be greatly endangered. If it be poured on per- acid gas, have no chemical action on each other. fectly dry charcoal powder, it excites combustion, If colorless nitric acid and muriatic acid of comwith the emission of copious fumes. By boiling merce be mixed together, the mixture immediit with sulphur it is decomposed, and its oxygen, ately becomes yellow, and gains the power of uniting with the sulphur, forms sulphuric acid. dissolving gold and platinum. If it be gently Chemists in general agree that it acts very pow- heated, pure chlorine arises from it, and the coerfully on almost all the metals; but Baumé bas lor becomes deeper. If the heat be longer conasserted, that it will not dissolve tin, and Dr. tinued, chlorine still rises, but mixed with nitrous Woodhouse of Pennsylvania affirms, that in a acid gas. When the process has been very long highly concentrated and pure state it acts not at continued till the color becomes very deep, no all on the silver, copper, or tin, though, with the more chlorine can be procured, and it loses its addition of a little water, its action on them is power of acting upon platinum and gold. It is very powerful.

now nitrous and muriatic acids. It appears then The nitric acid is of considerable use in the arts. from these observations, which have been very It is employed for etching on copper ; as a sol- often repeated, that nitro-muriatic acid owes its vent of tin to form with that metal a mordant for peculiar properties to a mutual decomposition some of the finest dyes ; in metallurgy and as- of the nitric and muriatic acids ; and that water, saying; in various chemical processes, on account chlorine, and nitrous acid gas, are the results. of the facility with which it parts with oxygen Though nitrous gas and chlorine have no action and dissolves metals; in medicine as a tonic, on each other when perfectly dry, yet if water and as a substitute for mercurial preparations in be present there is an immediate decomposition, syphylis and affections of the liver, as also in and nitrous acid and muriatic acid are formed. form of vapor to destroy contagion. For the 118 parts of strong liquid nitric acid being depurposes of the arts it is commonly used in a composed in this case, yield sixty-seven of chlodiluted state, and contaminated with the sulphu- rine. Aqua regia does not oxidise gold and ric and muriatic acids, by the name of aquafortis. platina. It merely causes their combination with This is generally prepared by mixing common chlorine. nitre with an equal weight of sulphate of iron, A bath made of nitro-muriatic acid, diluted so and half its weight of the same sulphate calcined, much as to taste no sourer than vinegar, or of and distilling the mixture; or by mixing nitre such a strength as to prick the skin a little, after with twice its weight of dry powdered clay, and being exposed to it for twenty minutes or half distilling in a reverberatory furnace. Two kinds an hour, has been introduced by Dr. Scott of are found in the shops, one called double aqua- Bombay as a remedy in chronic syphylis, a rafortis, which is about half the strength of nitric riety of ulcers and diseases of the skin, chronic acid; the other simply aquafortis which is half hepatitis, bilious dispositions, general debility, the strength of the double.

and languor. He considers every trial as quite A compound made by mixing two parts of the inconclusive where a ptyalism, some affection of nitric acid with one of muriatic, known formerly the gums, or some very evident constitutional efby the name of aqua regia, and now by that of fect, has not arisen from it. The internal use of nitro-muriatic acid, has the property of dissolv- the same acid has been recommended to be coning gold and platina. On mixing the two acids joined with that of the partial or general bath. heat is given out, an effervescence takes place, With the different bases the nitric acid forms and the mixture acouires an orange color. This nitrates.

The nitrate of barytes, when perfectly pure, is is heated, and passed through other tubs, until it in regular octahedral crystals, though it is some- becomes of considerable strength. It is then times obtained in small shining scales. It may carried to the boiler, and contains nitre and other be prepared by uniting barytes directly with ni- salts; the chief of which is common culinary tric acid, or by decomposing the carbonate or salt, and sometimes muriate of magnesia. It is sulphuret of barytes with this acid. Exposed to the property of nitre to be much more soluble heat it decrepitates, and at length gives out its in hot than cold water; but common salı is very acid, which is decomposed; but, if the heat be nearly as soluble in cold as in bot water. Whenurged too far, the barytes is apt to vitrify with ever, therefore, the evaporation is carried by the earth of the crucible. It is soluble in twelve boiling to a certain point, much of the common parts of cold, and three or four of boiling water. salt will fall to the bottom, for want of water to It is said to exist in some mineral waters. It hold it in solution, though the nitre will remain consists of 6.75 acid + 9-75 base.

suspended liy virtue of the heat. The common The nitrate of potash is the salt well known by salt thus separated is taken out with a perforated the name of nitre or saltpetre. It is found ready ladle, and a small quantity of the fluid is cooled, formed in the East Indies, in Spain, in the king - from time to time, that its concentration may lie dom of Naples, and elsewhere, in considerable known by the nitre which crystallises in it. quantities ; but nitrate of lime is still more When the Auid is sufliciently evaporated, it is abundant. Far the greater part of the nitrate taken out and cooled, and great part of the nitre made use of is produced by a combination of separates in crystals; while the remaining comcircumstances which tend to compose and con- mon salt continues dissolved, because equally dense nitric acid. This acid appears to be pro- soluble in cold and in hot water. Subsequent duced in all situations where animal matters are evaporation of the residue will separate more completely decomposed with access of air, and nitre in the same manner. By the suggestion of of proper substances with which it can readily Lavoisier, a much simpler plan was adopted; combine. Grounds frequently trodden by cartie, reducing the crude nitre to powder, and washing and impregnated with their excrements, or the it twice with water. walls of inhabited places, where putrid animal This nitre, which is called vitre of the first vapors abound, such as slaughter-houses, drains, boiling, contains some common salt; from which or the like, afford nitre by long exposure to the it may be purified by solution in a small quantity air. Artificial nitre beds are made by an atten- of water, and subsequent evaporation ; for the tion to the circumstances in which this salt is crystals thus obtained are much less contamiproduced by nature. Dry ditches are dug, and nated with common salt than before; because covered with sheds, open at the sides, to keep off the proportion of water is so much larger, with the rain : these are filled with animal substances respect to the small quantity contained by the

-such as dung, or other excrements, with the nitre, that very little of it will crystallise. For remains of vegetables, and old mortar, or other nice purposes, the solution and crystallisation of loose calcarcous earth; this substance being nitre are repeated four times. The crystals of found to be the best and most convenient recep- nitre are usually of the form of six-sided flattened tacle for the acid to combine with. Occasional prisms, with dihedral summits. Its taste is penewatering, and turning up from time to time, are trating; but the cold produced by placing the necessary to accelerate the process, and increase salt to dissolve in the mouth is such as to prethe surfaces to which the air may apply; but too dominate over the real tast at first. Seven parts inuch moisture is hurtful. When a certain por- of water dissolve two of nitre, at the temperature tion of nitrate is formed, the process appears to of 60°; but boiling water dissolves its own go on more quickly; but a certain quantity stops weight. 100 parts of alcohol, at a heat of 1769, it altogether, and after this cessation the mate- dissolve only 2.9. rials will go on to furnish more, if what is form- On being exposed to a gentle heat, nitre fuses; ed be extracted by lixiviation. After a succession and in this state being poured into moulds, so of many months, more or less, according to the as to form little round cakes, or balls, it is called management of the operation, in which the action sal prunella, or crystal mineral. This at least of a regular current of fresh air is of the greatest is the way in which this salt is now usually preimportance, nitre is found in the mass. If the pared, conformably to the directions of Boerbeds contained much vegetable matter, a consi- haave; though in most dispensatories a twentyderable portion of the nitrous salt will be com- fourth part of sulphur was directed to be mon salt petre; but if otherwise, the acid will, for deflagrated on the nitre before it was poured out. the most part, be combined with the calcareous This salt should not be left on the fire after il earth. It consists of 6.75 aciil + 6 potash. has entered into fusion, otherwise it will be con

To extract the saltpetre from the mass of verted into a nitrate of potash. If the heat be inearthy matter, a number of large casks are pre- creased to redness, the acid itself is decomposed, pared, with a cock at the bottom of tach, and a and a considerable quantity of tolerably pure quantity of straw within, to prevent its being oxygen gas is evolved, succeeded by nitrogen. stopped up. Into these the matter is put, to- This salt powerfully promotes the combustion gether with wood-ashes, either strewed at top, or of intlammable substances. Two or three parts added during the filling. Boiling water is then mixed with one of charcoal, and set on fire, barn poured on, and suffered to stand for some time; rapidly; azote and carbonic acid gas are given after which it is diawn ofi, and other water out, and a small portion of the latter is retained added in the same manner, as long as any saline by the alkaline residuum, which was formerly matter can be thus extracted. The weak brine called clyssus of nitre. Three parts of nitre, illo

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