Cooley's Cyclopaedia of Practical Receipts Volume Ii Part 71

_Obs._ No particular caution is required in preparing the above compound, except the use of too much heat. The temperature should be so arranged as to keep the melted ma.s.s in a state of gentle ebullition, and should not be allowed, under any circ.u.mstances, to exceed about 500 Fahr. Should white fumes appear within the retort after the evolution of the gas has commenced, the heat should be at once lowered, as, when heated to about 600, nitrate of ammonia explodes with violence.

Nitrous oxide may also be made in the same way, from crystallised nitrate of ammonia, or by exposing nitric oxide for some days over iron filings moistened with water, but, without great care, the product is not always fit for respiration. When pure, it is colourless, has an agreeable odour, and does not affect solution of nitrate of silver. See ANaeSTHETICS.

2. =Nitric oxide.= NO. _Syn._ DEUTOXIDE OF NITROGEN, NITROUS GAS, BINOXIDE OF NITROGEN; NITROGENEE BINOXYDUM, L. _Prep._ By pouring nitric acid, sp.

gr. 12, on metallic copper, in the form of turnings, clippings, or wire.

Effervescence ensues, and nitric oxide is evolved, and may be collected over water or mercury in the pneumatic trough. The residual liquid yields crystals of nitrate of copper on evaporation.

_Prop., &c._ A colourless, tasteless, inodorous, irrespirable, and incombustible gas. In contact with free oxygen, it produces dense orange or red vapours of nitric peroxide (NO_{2}), which are freely absorbed by water. Nitric oxide is absorbed by a solution of ferrous sulphate, which it turns of a deep brown or nearly black colour, which is removed by boiling. Sp. gr. 1039.

=Nitrous Anhydride.= N_{2}O_{3}. _Syn._ NITROGEN TRIOXIDE, ANHYDROUS NITROUS ACID. The easiest method of obtaining this compound consists in heating 1 part of powdered starch with 8 parts of nitric acid of sp. gr.

125, and pa.s.sing the evolved gases, first through a drying tube two feet long containing fused chloride of calcium, and then into a dry and empty U-tube cooled to 20 Fahr. by surrounding it with a mixture of pounded ice and crystallised chloride of calcium. Nitrous anhydride thus produced is a blue liquid which emits red fumes, and which on admixture with water at ordinary temperatures is decomposed, producing nitric acid and nitric oxide. If nitrous anhydride be mixed with water at temperatures below 0 Fahr. the two combine, and a blue solution is formed which (probably) contains nitrous acid (HNO_{2}). See NITROUS ACID.

=Nitrogen Pentoxide.= N_{2}O_{5}. _Syn._ NITRIC PENTOXIDE, NITRIC ANHYDRIDE, ANHYDROUS NITRIC ACID. See NITRIC ACID (ANHYDROUS).

=Nitrogen Peroxide.= NO_{2}. _Syn._ NITRIC PEROXIDE, PEROXIDE OF NITROGEN, NITROGEN TETROXIDE, HYPONITRIC ANHYDRIDE. This compound forms the chief const.i.tuent of the red fumes which develop on mixing nitric oxide with air or oxygen. It is most readily prepared by heating thoroughly dried nitrate of lead in a retort, and conducting the evolved gases into a U-tube surrounded with a freezing mixture of ice and salt for the purpose of condensing the nitric peroxide. If the U-tube be perfectly dry, and the cold intense, the nitric peroxide obtained a.s.sumes the form of transparent crystals, but the presence of the slightest trace of moisture prevents their formation and produces instead a colourless liquid which, as the temperature rises, acquires a yellow and ultimately a red colour. Nitric peroxide dissolves in nitric acid and turns it of a yellow or red hue. The so-called '_nitrous acid_' or '_fuming nitric acid_' of commerce owes its deep red colour to the presence of this compound. At very low temperatures water converts nitric peroxide into nitric and nitrous acids; at ordinary temperatures it transforms it into nitric acid, nitrous acid, and nitric oxide.

=NITRO-GLYCERIN.= _Syn._ GLONOIN, NITRATE OF GLYCERYL, TRINITRITE, NITROLEUM, FULMINATING OIL, TRI-NITROGLYCERIN. This dangerously explosive compound, from the use of which in mining, quarrying, and such like operations so many fatal accidents have occurred, is glycerin in which 3 atoms of hydrogen have been replaced by 3 molecules of nitroxyl (NO_{2}), as ill.u.s.trated by the following formulae:

Glycerin. Nitro-glycerin.

C_{3}H_{5} } (H } ) = C_{3}H_{5} } (H } ) }O_{3} + 3 ( }O ) } O_{3} + 3 ( } O) H_{3} } (NO_{2} } ) (NO_{2})_{3} } (H } )

It was discovered in 1847 by Dr. Sobrero, a pupil of Pelouze.

Kopp prepares nitro glycerin by mixing 3 parts of sulphuric acid, of sp.

gr. of 1767, with 1 part of fuming nitric acid. 2800 grammes of the mixed acids are added to 350 grammes of glycerin, great care being necessary to avoid any elevation of temperature, which would lead to a violent reaction, resulting in the conversion of the glycerin into oxalic acid.

After standing 5 or 10 minutes, the mixture is poured into four or six times its bulk of very cold water to which a rotatory motion has been imparted. The nitro-glycerin falls to the bottom of the vessel as an oily-looking liquid, which is washed by decantation. The manufacture of nitro-glycerin is attended with considerable danger, since very slight friction or pressure is sufficient to determine its explosion. Hence many methods have been suggested for guarding against accidents from it during storage. One of these consists in mixing it with finely powdered gla.s.s.

Wurtz advises the nitro-glycerin to be mixed with solutions of nitrate of lime, zinc, or magnesia, the solutions to have a sp. gr. equal to the nitro-glycerin. By this means a harmless emulsion would be formed, and the nitro-glycerin would be recoverable when required for use by simply adding water. n.o.bel's plan consists in dissolving it in wood spirit.

_Prop._ Nitro-glycerin is a fluid of a yellow or brownish colour, having a sp. gr. of 16. It dissolves in alcohol, ether, and wood naphtha, from all of which it may be recovered by the addition of water. Dissolved in either of these solutions it becomes converted into a crystalline ma.s.s when exposed to a low temperature. If subjected to a blow it explodes with fearful violence, a single drop placed upon paper, and struck upon an anvil, giving rise to a report that is almost deafening. Neither a spark nor the application of a lighted body is said to cause its ignition, which takes place with difficulty even if it be applied to a thin layer of the substance. 100 parts of nitro-glycerin yield on combustion:

Water 20 parts.

Carbonic acid 58 "

Oxygen 35 "

Nitrogen 185 "

------ 1000[48]

[Footnote 48: Wagner.]

As the specific gravity of nitro-glycerin is 16, one part by bulk will yield by combustion:--

Aqueous vapour 554 volumes.

Carbonic acid 469 "

Oxygen 39 "

Nitrogen 236 "

------ 1298[48] "

Other experimenters affirm that, instead of free oxygen, nitrous oxide is one of the products of the combustion of nitro-glycerin. According to n.o.bel the heat liberated when nitro-glycerin is exploded, causes the expansion of the gases to be eight times their original bulk; therefore, one volume of the substance will yield 10,384 volumes of gas, whilst one part by bulk of gunpowder only yields 800 volumes of gas. If these data be correct the explosive force of nitro-glycerin is thirteen times greater than that of powder, bulk for bulk, and eight times greater weight for weight.

Bottger has devised a process for the preparation of nitro-glycerin, which being, as he affirms, entirely free from danger, adapts it for lecture experiments:--A few grains of pure glycerin, free from water, is poured into a test-tube, which is surrounded by a freezing mixture, and containing a mixture of one volume of the most concentrated nitric acid (152 sp. gr.), and two volumes of the strongest sulphuric acid (183 sp.

gr.). Then, as quickly as possible, the whole is poured into a larger quant.i.ty of cold water. The nitro-glycerin, which has formed like oil drops, sinks rapidly to the bottom, being specifically the heavier liquid.

It is then washed several times by decantation with fresh water, and, lastly, with a weak solution of soda.

Remove the water with a few pieces of fused chloride of calcium. Then the nitro-glycerin is in such purity that it may, without danger, be kept any length of time for lecture experiments.

=NITRO-HYDROCHLO'RIC ACID.= _Syn._ NITRO-MURIATIC ACID; AQUA REGIA, ACIDUM NITRO-HYDROCHLORIc.u.m (B. P.), A NITRO-MURIATIc.u.m, L.; EAU ReGALE, Fr.

_Prep._ 1. (B. P.) Nitric acid, 3; hydrochloric acid, 4; water, 25. Mix the acids twenty-four hours before adding the water. (This precaution is necessary to allow of the development of the chlorine, and the chloronitrous and chloronitric gases which result from the mutual decomposition of the two acids, and upon which the therapeutic activity of the agent depends). Colourless. Keep the mixture in a cool and dark place.

2. (Ph. D. 1826). Nitric acid, 1 part; hydrochloric acid, 2 parts (both by measure); mix in a refrigerated bottle, and keep the mixture in a cold and dark place. Used to dissolve gold and platinum; and in medicine, in liver complaints, syphilis, the exanthemata, &c., either externally, in doses of 5 to 15 drops in water, or externally, as a foot- or knee-bath. It is also occasionally employed as a caustic.

3. (AQUA REGIA WITH SAL AMMONIAC.) Nitric acid (sp. gr. 12), 16 fl. oz.; sal ammoniac, 4 oz.; dissolve. Occasionally used by dyers; does not keep well.

4. (DYERS' AQUAFORTIS.) Colourless nitric acid (sp. gr. 117), 10 lbs.; hydrochloric acid (sp. gr. 119), 1 lb.; mix. Used by dyers.

=NITRO-PRUS'SIDES.= A series of salts discovered by Dr Playfair, and obtained by the action of nitric acid on the ferrocyanides and ferridcyanides. The most important of these salts is the nitroprusside of sodium (NA_{2} (NO) FeCy_{5}. 2Aq.). _Prep._ Dissolve 2 parts of powdered ferrocyanide of sodium in 5 parts of common nitric acid, previously diluted with its own volume of water. When the evolution of gas has ceased, digest the solution on a water bath until it no longer yields a blue but slate-coloured precipitate with ferrous sulphate. Cool the liquid, filter, neutralise the filtrate with carbonate of sodium, and again filter. This filtrate, on evaporation, yields crystals consisting of a mixture of nitro-prusside of sodium and nitrate of pota.s.sium; the former, which may be recognised by their rhombic shape and their fine ruling colour, should be picked out and preserved.--_Use._ As a test for soluble sulphides, with which nitro-prusside of sodium strikes a beautiful violet tint. According to Playfair this is the most delicate test for alkaline sulphides.

=NI'TROUS ACID.= HNO_{2} See NITROUS ANHYDRIDE, under NITROGEN, OXIDES OF.

=NITROUS OXIDE.= See NITROGEN, OXIDES OF.

=NODE.= _Syn._ NODUS, L. A hard tumour proceeding from a bone, and caused by the swelling of its external membrane. The bones of the leg, forehead, and forearm, are those most commonly attacked. Nodes are generally accompanied with considerable pain, and often with caries and loss of vitality.

=NOLI ME TANGERE.= See LUPUS.

=NOMENCLATURE (Chemical).= The following information will doubtless prove useful to many of our readers, as serving to explain terms which are necessarily of frequent occurrence in this work:

ACIDS.--_a._ When a substance produces only one acid compound, the name of this acid is formed by adding the termination -IC to that of the radical, or to the leading or characteristic portion of it; as sulphuric acid, an acid of sulphur. This is Latinised by changing -IC into -Ic.u.m; as, _acidum, sulphur_Ic.u.m.--_b._ When a body forms two acid compounds containing oxygen, the name of the one containing the smaller proportion of that substance ends in -OUS; as _nitr_OUS acid, which contains 1 atom of nitrogen and 2 of oxygen; _nitr_IC acid, containing 1 atom of nitrogen and 3 of oxygen. In this case the Latin name ends in -OSUM; as, _acidum nitr_OSUM.--_c._ When a substance forms more than two acids with oxygen, the Greek preposition HYPO- (below or under) is prefixed to the name of the acid in -OUS or -IC next above it; as, HYPO_chlorous acid_.--_d._ When a new acid compound of a substance is discovered, containing more oxygen than another acid of the same substances already known, the name of which ends in -IC, the prefix PER- or HYPER- is added; as, PER_iodic acid_. This may be ill.u.s.trated by the oxygen acids of chlorine:--

Hypochlorous acid (_acidum hypochlorosum_) HClO Chlorous " ( " _chlorosum_) HClO_{2} Chloric " ( " _chloric.u.m_) HClO_{3} Perchloric or} Hyperchloric } " ( " _perchloric.u.m_) HClO_{4}

=OXIDES.= The names of these have, in general, reference to the number of atoms of oxygen which they contain. When a metal forms only one basic compound with oxygen, this compound is simply called the oxide of such base; but as most substances form more than one compound with oxygen, certain prefixes are introduced to express the proportions. In such cases it is generally found that one out of the number has a strongly marked basic character, and contains 1 atom of each of its const.i.tuents. This is called the oxide, protoxide, or monoxide, and forms the standard to which those both above and below it are preferred. Thus, supposing M to be the metal, we may have:--

Suboxide or dioxide (_suboxydum_, _dioxydum_) M_{2}O Oxide, protoxide, or monoxide (_oxydum_, _protoxydum_) MO Sesquioxide (_sesquioxydum_) M_{2}O_{3} Binoxide, dioxide, or deutoxide (_binoxydum_, _deutoxydum_) MO_{2} Teroxide or trioxide (_teroxydum_, _tritoxydum_) MO_{3} {That containing {the _largest_ Peroxide (_peroxydum_) {proportion of {oxygen.

SALTS.--_a._ Acids having names ending in -IC give rise to salts whose names end in ATE; thus _nitr_IC acid yields _nitr_ATES, e.g. _nitrate of silver_. -ATE is Latinised by -AS, e.g. _nitrate of silver_ becomes _argenti nitr_AS.

_b._ Acids possessing names ending in -OUS form salts having names ending in -ITE; thus _sulphur_OUS _acid_ produces _sulph_ITES, e.g. _sulphite of sodium_. -ITE is Latinised by -IS; e.g. _sulphite of sodium_ becomes _sulph_IS.

_c._ The preceding names are presumed to refer to neutral compounds. In _acid_ salts the prefixes noticed above are added to express the preponderance of the acid radical over the metal. KHSO_{4} is called _acid sulphate of pota.s.sium_, BI_sulphate of pota.s.sium_, or BI_sulphate of potash_, the neutral sulphate being K_{2}SO_{4}.

_d._ In _basic_ salts, or those in which the metal is in excess of the acid radical, the prefixes -SUB and -DI are employed; _e.g._ the formula of _neutral_ acetate of lead is PbA_{2}. This salt, when boiled with oxide of lead (a base), furnishes [PbA_{2}PbO] and [PbA_{2}2PbO]. They are both, therefore, _basic_ acetates; and to distinguish one from the other the former is called DI_acetate_ and the latter TRI_acetate_ of lead; _-di_ referring to the presence of two atoms of lead and _-tri_ to three.

Formerly the salts of the metals of the alkalies and alkaline earths received names which indicated the existence in them of the oxides of such metals. Thus, the terms carbonate of soda, nitrate of potash, carbonate of lime, sulphate of magnesia, names by which these fluids are still designated by some chemists are now subst.i.tuted by the more systematic and less speculative names of carbonate of sodium, nitrate of pota.s.sium, carbonate of calcium, and sulphate of magnesium. Another, and in the opinion of the editor, a still better system of nomenclature is that in which the metallic or basic radical is mentioned first; _e.g._ calcium sulphate instead of sulphate of calcium, ammonium chloride for chloride of ammonium. When the _same_ radicals form more than one series of salts, each series is distinguished by appending the terminations -IC and -OUS to that part of the name which refer to the basic radical; _e.g._ _mercur_OUS _chloride_ (HgCl), _mercur_IC _chloride_(HgCl_{2}); _ferr_OUS _sulphate_ (FeSO_{4}), _ferr_IC _sulphate_(Fe_{2}(SO_{4})_{3}).

NON-METALLIC BODIES, &c. The names of the compounds formed by the union of the non-metallic elements, and certain other bodies, with the metals and with each other, either terminate in -IDE, Latinised by -IDUM, or in -URET, Latinised by -URETUM; as, _a.r.s.en_IDE or _a.r.s.eni_URET (_a.r.s.en_IDUM, _a.r.s.eni_URETUM), _brom_IDE, _carb_IDE or _carb_URET, _chlor_IDE, _cyan_IDE _fluor_IDE, _hydr_IDE, _iod_IDE, _sulph_IDE or _sulph_URET, &c. The first of these terminations now prevails among English scientific chemists. The prefixes already noticed are also employed here.

METALS. The names of the metals (those of them, at least, that have been given during the present century) end in -IUM or (less frequently) in -UM; as _pota.s.s_IUM, _sod_IUM, _platin_UM. The Latin names of several of the non-metallic elementary bodies also end in -IUM; as, _iodin_IUM, _nitrogen_IUM, &c.