N A C
NEP
( 134 )
.-addition of ammonia produced any precipi-tate. Thus only 24J grains, or one-third of-the magnefia could be feparated by any addi-tion of ammonia, though the quantity of the.latter was more than fuificient to faturate the.muriatic acid. The remaining liquor yields byHow evaporation fmall polyhedral cryftals, which-have a bitter and ammoniacal tafte, and are the.muriat of magnefia with ammonia. The compo-iition of this fait is inferred from the quantity•of magnefia feparated from the folution in the.above-mentioned experiment: the 24J grainsof precipitated magnefia faturated with muriatic.acid and evaporated flowly, fo as to become aconfufedly cryftallized mafs, produced 98 grs.;of muriated magnefia.; hence the 48 grains ofmagnefia remaining in the folution would pro-duce about 196 grs. of muriat, which remained.in the triple fait. Then as 24^ grs. of magnefiawere difplaced by the ammonia, it is eftimated.that as much ammonia remains in the triplefait as is neceffary to faturate as much muriaticacid as will faturate 24? grains of magnefia.From thefe data M. Fourcroy eftimates theproportion of this triple fait to be 73 per cent.of muriat of magnefia, and 27 of muriat ofammonia. It would be eafy however to fliewthat thefe data are far from fufficient, and itdoes not appear that they have been confirmedby analyfis.
• This triple fait may alfo be formed by themixture of concentrated folutions of muriatedammonia and muriated magnefia, whereby thefait readily feparates in fmall cryftals. Magnefiaagitated with a- cold folution of muriated am-monia will alfo produce the fait.
The ammoriiaco-magnefian muriat is readilydecompofable by heat, the muriat of ammoniabecomes volatilized, the whole of the muriatic.acid flies off, and the magnefia alone is left.
This fait is not deliquefcent as the fimplemuriat of magnefia is : it difiolves in fix or fevenparts of cold water, and in lefs when hot. Itis obvioully lefs foluble than either of the mu-riats of which it is compofed, fmce it feparatesin cryftals when the folutions of each aremixed.
Muriat of Alumine.
This fait is never found native. It is pre-pared by boiling muriatic acid on alumine for aconfiderable time, whereby a folution is effettedwhich is always acidulous and has a very ftypticauftere tafte. When evaporated to a thick con-fidence it takes a gelatinous form, but cannotbe cryftallized but with extreme difficulty.
This fait is very foluble in water. Likethe muriat of magnefia, it parts with the wholeof its acid by heat, and the alumine remainspure. The fait when brought to a gelatinousconfidence, is extremely deliquefcent in the air.
It is not applied to any ufe. According toRichter, 21.8 grains of alumine gave 10® ofthe muriat, evaporated fo as to become fenfiblydry.
Muriat of Zircon, &c.
(For the other Muriated Earths, fee thefe Earths reflectively}.
MURICALCITE. See Bitterspath.
MUSCLE, or Muscular Fibre.
The chemical analyfis of mufcular fibre willbe found under the articles Fibrin and Blood .
N
This term is applied to that beautiful naturalwhite enamel which forms the greater part ofthe fubftance of the oyfter-fliell, particularly thepearl-oyfter. Its chemical compofition will bedeferibed under the article Shell.
NADELSTEIN. See Titanium.
NAPTFIA. See Bitumen.
NATRON, is a term commonly applied to.Soda, and particularly its Carbonat .
NEPHRITE. -
Gf this mineral there are the two followingfubfpecies.
1. Subfp. Common Nephrite or Jade. Ge-meiner Nephrit, Wern. Nephrite commun, Broch.
Its .colour is a fomewhat dark leek-green
• Emmeiling* Kirsvan,
verging to blue, or greenifh or bluifh white.It occurs maffive and in' detached roundedpieces. The fmooth external furface is glim-mering with an oily luftre ; internally it is dullexcept when mixed with fibres of afibeft andfeales of talc. Its fracture is coarfe fplinteryand fometimes obfeurely fibrous. Its fragmentsare indeterminately angular. It is more or lefstranflucent; it is hard, difficultly frangible andgreafy to the touch. Sp. gr. of the Oriental2.97 to 3.04, of the Swifs 3.31 to 3.38.
Nephrite by expofure to a moderate heat be-comes more brittle and femi-tranfparent: it isfufible before the blowpipe without additioninto a white femi-tranfparent glafs.
Of the geological hifiory of this mineral no-Jamcfon, Brochant.