Page:Cyclopaedia, Chambers - Supplement, Volume 2.djvu/127

 N I T

N O C

ufe to form the whole inte a body, and give it form and con- fidence, than to add to any of its fat. NITRUM, is ufed by the poet Martial to exprefs that fort of foulnefs in cryftal, v/hich Pliny, and other of the antient Roman authors, diftinguifh by the name offal. See the article Sal. NfeTRWM anthmniatmn, in chemifrry, the name of a fait pro- cured bv evaporating the filtrated waters ufed in making the antimonium diapbireikum to a drynefs, continually ftirring them towards the end of the operation. There, at length, remains from thefe a white fabric matter, of a particular tafte, not un- grateful, nor nitrous, but perfectly mild.

Hence we fee that nitre is changed into a new fait by detona- tion with antimony.

This fait is gently aperitive, and, in denfc, inflammatory blood, excellently refolves without violence. It fuccefsfully promotes perfpiration, fweat, and urine j hence it cools, and becomes greatly ferviccable in the fmall pox, meafles, pleurify, and peripneumony. We fee how erroneous has been the opi- nion of this water being noxious, and how valuable a medi- cine that opinion had led people for a long time to throw away. N-ITROM cehirtum, in natural hiftory, a name given by Dr. Lif- ter to a peculiar fpecies of neutral fait, which he firft publick- ]y defcribed in his book on the medicinal waters of England. He very improperly calls it niire; becaufe it has none of the properties or qualities of nitre, but only a fort of general re- femblance in its external form. He obferves that this fait, tho' very little known, was abundantly the moft copious of ai! the forts afforded by the mineral waters in genera! ; and fays its cryftals were long and (lender, and confuted of four fides, and were terminated by a point compofed of two triangular planes. He adds, that this fait doubtlefs had its origin from a mixture of the acid of fulphur, and a calcai ious earth of an alkaline na- ture.

This fait is found in almoft all the mineral waters of Ger- many, and is very juftly obferved by Hoffman to be of the na- ture, of Glauber's fait: that it is not nitre is evident from this, that it is not inflammable, nor will yield aqua fortis by diftil- lation. It feems, indeed, true Glauber's fait, compofed of the acid of vitriol, or fulphur, for this is in both the fame, and of that alkaline earth which is the bafis of fea fait : this is its origin, in the veflels of the chemift, as well as in the bowels of the earth, and probably the figure of the cryftals of that obferved by Dr. Lifter, was the fame in the point, as well as in the bo- dy, both being quadrilateral columns terminated by pyramids compofed of a number of triangular planes. Hoffman Opera, ■T. 5. p. 139.

This number in Glauber's fait is four, though Dr. Lifter obferved only two in the fait he examined ; but it is frequently feen in the factitious, or common Glauber's fait, which natu- rally has four planes in the pyramid, that two of them are fo fmal!, as fcarce to appear more than flat fparks at the verge of the point ; in almoir. all the cryftals, one of the four is thus fmall, fo that they feem to confift only of three, while the whole four are truly there. The fame is the cafe frequently in the common rock cryftal, whofe pyramid ought to confift of fix planes, and, in truth, always does fo, but one or more of them are frequently fo fmall, that a hafty obferver would fay it confided only of four or of five planes. If this may be allowed to be the cafe, in regard to Dr. Lifter's observation of his cryftals, there feems no doubt but that his mtrum calcarium is true and genuine Glauber's fait, as much as that of the chemift's laboratory ; and, according to his own jult obfervation, it is compofed of the very fame principles with that chemical (alt. The mineral waters of Egra abound with this fait, which Hoffman alfo has called, for that reafon, fat iTgrrtWHw, when Separated from them by evaporation ; but none contains fo great a proportion of it as the Sedelitz waters, a pint of which, on evaporation, leaves two drams of it. The medicinal waters in the neighbourhood of Paris con- tain it alfo in a very confiderable quantity, though lefs than this. _ It is the opinion of Hoffman, that when any water be- fore impregnated with a vitriolic acid, in its current under ground, paflcs over this calcarious earth, it as readily joins a part of it with it, as the vitriolic acta does with the fea fait, or its bafis, in the making the common Glauber's fait, and thence produces a hitter purging fait, of the fame nature with that ; and, indeed, if the acid of fulphur be mixed with any alkaline Jubilance, a bitter neutral fait is produced, fomewhat analo- gous to this, and to the Glauber's fait. Nitrum nitratum, in chemiftry, the name of a preparation of nitre, made by adding a fufficient quantity of fpirit of nitre to a hxiymm of pure nitre, and afterwards evaporating it to a pellicle, and fetting it by to fhoot. The cryftals formed by this liquor are perfe% nitrous in their figure, but they will be of an acid tafte J

We fee by this, that it is poffible to alter a fait, and to reduce it into the appearance of a different body, by means of fub- itances before feparated from itfelf ; and, in this cafe, the al- teration is made, in almoft any degree, at plcafurc ; the fait produced being mure or lefs acid, as more or lefs of the acid Jpint is ufed : but it is to be obferved that the more acid there is ufed, the more difficultly the fait dries, and the more dim- Sufpl. Vol. II.

cultly it is kept dry, it being always fubje& to run in the air. This preparation of nitre is a good medicine in burning fevers. Boerbaave's Chem. Part 2. p. 176. Nitrum pur if -alum, pur fed nitre, is thus prepared : take nitre, or common falt-petre, one pound ; pure water three quarts and a pint ; fet them on the fire together, and diffblve the fait per- fectly by boiling : then ftrain the hot lixivium through a dou- ble flannel, and fet it over the fire again in an earthem veffel. Evaporate it gently, till on taking out a little of the liquor in a fpoon as it cools, there are feen threads as it were fhooting in it ; in this ftate the fait is ready to concrete. Set it in a cool place, putting clean fticks acrofs the veffel, and the fait will form itfeif into extremely pure and beautiful cryftals on the fide of the veffel, but principally on the fticks. Thefe dried in a colander are fit for ufe.

This is the beft of all the preparations of nitre, for medicinal ufe, in its native form. It diflblves immediately on en- tering the body, where it wonderfully cools, and thins the blood, giving it a fine florid colour. In all inflammatory dif- eafes attended with condenfations of the blood, this fait proves excellently cooling and attenuating. It is given from four or five grains to ten, twelve, or fifteen at a dofe. Some give more at a time, but it is more advifeable to have the dofes fmallcr, and oftener repeated. It is alfo good in the fmall-pox, and fuppreffions of urine. It is alfo faid to be given by many in hemorrhages with fuccefs. If there be any cafe in which caution is required, it is in a confumption where the lungs are ulcerated.

NiTRUMw^to, a name given by the chemifts to a preparation of nitre, which very readily ihcots out into beautiful cryftaHi- zations. If, in the making GLuber's fpirit of nitre, there are ufed four parts of nitre, and one of oil of vitriol, and the fpirit be entirely driven off", the white fait remaining dry in the re- tort, on being expofed to the open air, will foon ' be covered with a thick and long down, as if it grew ; but if this fait be diftblved in water, and there ftrained, and evaporated to a dr ■- nefs, in a cylindrical glafs, and kept expofed to the open air, its upper furface will often appear covered with beautiful branching little plants, all which will diffblve away upon the application of heat, and leave the furface even ; but upon ex- pofing the vcffd again to the open air, in a quiet place, they will grow again as before, thus feveral times exhibiting the re- fufcitarion of plants, as it were, from their own afhes. Some chemifts have formed feveral fables upon fome fuch ba- fis as this i and, very probably, the whole fecret of their ope- rations was no more than a concealed fraud of this kind, this having nothing to do with vegetation.

Nitrum vitriolatum, a preparation of nitre made as follows; Diffblve the mafs left in the retort after diftiilarion of a fpirit of nitre, in about eight times its weight of water ; filtrate the folution, and, when perfectly clear, evaporate the liquor to fuch a ftandard, that the fait will no longer be fuftained in it ; then fet it in a cool place, and collect the fait as it fhoots, lay- ing it in an earthen colander to dry. This is of much the fame virtues with tartarum vitriolatum, and is frequently fold under its name. See Tartarum vitriolatum.

NIVALIS avis, the fnmu-bird, a name given by authors to a bird common in Poland in the fevereft months of the winter, and at no other time. The country people call it fmegu'sa, which figniResfuoiv-bird alfo : it is obferved to come with thefnows, and go away again with them. The country people ufe to prefage the mildnefs, or the feverity of the fucceeding winter from their flights in greater or in fmaller numbers, or earlier, or later, in the feafon.

NIURI, in botany, the name of a genus of plants, called by Linnaeus phy'.lanthus. Hort. Mai. 10. 27. Seethe article Ph yll anthus.

NOAH's ark jhell, in natural hiftory, the name of a kind of fea ihcll, which authors were always puzzled about referring to any genus, till a late French author has referred it to a new genus he has made under the title cordiformis, taking in the bucardia, and triangular heart-fhells. The cabinets of the cu- rious afford us three fpecies of this fhell ;. the common kind, a. yellow and while kind, with broad irregular lines, and a varie- gated kind. Hift. Nat. Eclair, p. 333.

Mathiolus and Rondelet'ius have called the noalis ark fljeil, rhomboldes, and muf cuius Jlyiatus; and Lifter, who has followed thefe authors, has placed it among the mufcles. Rumphius has placed it among the pec~tens, and lome have made it a fpe- cies of oyfter. The impropriety of its arrangement under anv of thefe <renera is very obvious from the characters of each. It is indeed of a fomewhat different figure from the genera- lity of heart- fhells, as it is from all the other {hells in the world, but it agrees with them in its general character, for it is deeply ftriated, as they all are j and it is of a figure, in fome meafure, refembling that of a heart, though running out into an irregular length at the point.

We have another fhell of this genus which no one ever doubt- ed to belong to it, which yet is of an oblong figure, and fo much refembles the Noah's ark, as to plainly Slew they ought both to be reckoned fpecies of the fame genus. This is the oblong bucardium, or ox heart fhell, commonly called the laf- ia'rd A 'cab's ark. ,

NOCERIANA terra, earth of'h'ocera, in the materia medica, a E e white