NIT .
Nitrat of magnefia is decompofable with ab-ftraftion of its acid by the fixed alkalies; bybarytes, ftrontian, and lime, the magnefia in allthefe cafes being precipitated. Ammonia onlyin part decompofes this fait, forming with thereft a triple compound, the ammoniaco-mag-nefian nitrat. The fulphuric, phofphoric, andfluoric acids, with many of their neutral falts,decompofe nitrat of magnefia, the earth com-bining with the added acid. If to a ftrongfolution of this fait, nitrat of lime alfo in denfefolution be added, a precipitation of the mag-nefian nitrat takes place, being deprived of itswater of folution by the nitrat of lime.
Its component parts according to Kirwan are46 Nitric acid22 Magnefia32 Water
too
It is not made any ufe of.Ammoniaco-magnesian Nitrat .
This fait appears in the form of flender acicu-Iar prifms : to the tafte it is bitter, acrid, andammoniacal. It is prepared by a partial de-compofition of nitrat of ammonia by magnefia,or of nitrated magnefia by ammonia, or, Hillbetter, by the direct union of the folutions ofnitrat of ammonia and nitrat of magnefia.
By long expofure to the air it attracts a cer-tain quantity of moifture, though it does notdeliquiate. It requires eleven times its weightof water at the ordinary temperature for itsfolution, but a confidejrably fmaller proportionof boiling water; hence this latter folution de-• pofit? cryftals as it cools.
It is not decompofable by ammonia, but isfo by the fixed alkalies and by all the alkalineearths, even magnefia; the ammonia being dif-engaged. When dropped into a red hot cru-cible it undergoes a flight inflammation-. Byexpofure to a more gradual heat in a retort itgives out oxygen gas, nitrous vapour, nitricacid, azot and water, the ammonia being en-tirely decompofed; pure magnefia remains be-hind.
It is compofed according to Fourcroy of78 Nitrat of magnefia22 Nitrat of ammonia-
fometimes though rarely it is obtained in theform of foft thin pliable cryftalline plates. lothe tafte it is four and aftringent, it reddensblue vegetable colours and therefore containsan excels of acid. It has not been found nativebut may be prepared by digefting pure alumine,or the precipitated earth of alum in nitric acid.In the latter cafe the earth is diffolved withefFervefcence on account of a portion of carbon-ated alkali remaining in it, and this folutionfor the fame reafon is more readily cryftallizablethan when pure alumine is employed. Byexpofure to the air it foon deliquiates. It isvery foluble in water either hot of cold, and byevaporation and cooling generally takes theconfiftence of jelly. It produces neither flamenor detonation by being heated with combuf-tible bodies. When diftilled per fc the acidflies off at a moderate temperature, leaving theearth behind in a ftate of purity. It is decom-pofable by fulphuric and muriatic acids and byall the alkaline bafes. It is not made any ufeof.
["Glycine. See Glycine.
Nitrat of-c Yttria. See Gadolinite-1_Zircon. See Zircon.
Nitrite of Potash, or Phlogifticated Nitre.
We have already mentioned that nitrous acidis compofed of nitric acid and nitron's vapour.Now if nitrous acid and potafli be mixed to-gether the former is decompofed;- its nitricacid combines with the alkali forming nitre,while the nitrous vapour affumes a gaffeousftate and flies off. Hence it appears that nofuch fait as nitrite of potafli can be made by thedirect addition of its ingredients. We arcindebted however to the fagacity of Bergmanand Scheele for the interefting faft that if com-mon nitre be melted per>fe and kept in this ftatetill part of its oxygen is driven off, the refidualfait is a proper nitrite of potafh. In' this ftateit deliquiates-by expofure to the air and is do-compofable by the addition of vinegar and anyof tlie ftronge-r acids, red nitrous vapour beinggiven out. Dr. Thomfon is of opinion thatnitrite of potafli differs from the nitrat only inbeing faturated with nitrous gas : if this be the-cafe the common nitrite ought to contain aaexcels of alkali.
It is made no ufe of:
Of the other nitrites nothing is known withany certainty.
NITROUS GAS, or Nitrous Air.
This fubftance has already been mentionedunder the articles Nitric acid and Euchometry 3(to which we fhall refer our readers) and many