Chapter V: Part 5

_b._ Nitrous gas exposed to a large surface of zinc, in contact with water, is slowly converted into nitrous oxide; at the same time that ammoniac is generated, and white oxide of zinc formed. This process appears to depend, like the last, upon the decomposition of water by the affinities of part of the oxygene and nitrogene of nitrous gas, for its hydrogene, to form ammoniac and water; and by that of zinc for its oxygene. Zinc placed in contact with water, and confined by mercury,[139] decomposes it at the common temperature. Zinc, when perfectly dry, does not in the slightest degree act upon nitrous gas.

[139] As I have found by experiment.

I have not been able to determine exactly the diminution of volume of nitrous gas, during its conversion into nitrous oxide by zinc. In one experiment 20 measures of nitrous gas, containing about,03 nitrogene, were diminished to 9, after an exposure of eight days to wetted zinc; but from an accident, I was not able to ascertain the exact quantity of nitrous oxide formed.

_c._ It is probable that most of the imperfect metals will be found capable of oxydation, by the decomposition of water, when its hydrogene is attracted by the oxygene and nitrogene of nitrous gas. I have this day (April 14, 1800), examined two portions of nitrous gas, one of which had been exposed to copper filings, and the other to powder of tin, for twenty-three days.

The gas that had been exposed to copper was diminished nearly two fifths. The taper burnt in it with an enlarged flame, blue at the edges. Hence it evidently contained nitrous oxide.

The nitrous gas in contact with tin had undergone a diminution of one fourth only, and did not support flame.

VI. _Miscellaneous Observations on the conversion of Nitrous Gas into Nitrous Oxide._

_a._ Dr. Priestley found nitrous gas exposed to a mixture of iron filings and sulphur, with water, converted after a certain time, into nitrous oxide. Sulphurated hydrogene is always produced during the combination of iron and sulphur, when they are in contact with water; and by the hydrogene of this in the nascent state, the nitrous gas is most probably decomposed.

_b._ Green oxide of iron moistened with water, exposed to nitrous gas, slowly gains an orange tinge, whilst the gas is diminished. Most likely it is converted into nitrous oxide; but this I have not ascertained.

_c._ I exposed nitrous gas, to the following bodies over mercury for many days, without any diminution, or apparent change in its properties. Alcohol, saccharine matter, hydrocarbonate, sulphureous acid, and phosphorus.

_d._ Crystalised sulphate, and muriate of iron, absorb a small quantity of nitrous gas, and become dark colored on the outside; but after this absorption, (which probably depends on their water of crystalisation,) has taken place, no change is effected in the gas remaining.

_e._ The power of iron to decompose water being much increased by increase of temperature, nitrous gas is converted into nitrous oxide much more rapidly when placed in contact with a surface of heated iron, than when exposed to it at common temperatures. During the decomposition of nitrous gas in this way, ammoniac[140] is formed.

_f._ The curious experiments of Rouppe,[141] on the absorption of gases by charcoal, compared with the phænomena noticed in this Division, render it probable that hydrogene in a state of loose combination with charcoal, will be found to convert nitrous gas into nitrous oxide.

[140] As was observed by Milner. Nitrous gas passed over heated zinc, or tin, I doubt not will be found converted into nitrous oxide.

[141] Annales de Chimie, xxxii. p. 3.

VII. _Recapitulation of conclusions concerning the conversion of Nitrous Gas into Nitrous Oxide._

_a._ Certain bodies having a strong affinity for oxygene, as the sulphites, dry sulphures, muriate of tin, &c. convert nitrous gas into nitrous oxide, by simply attracting a portion of its oxygene; whilst the remaining oxygene enters into combination with the nitrogene, and they assume a more condensed state of existence.

_b._ Nitrous gas is converted into nitrous oxide by hydrogene, in a peculiar state of existence, as in sulphurated hydrogene; and that by a series of very complex affinities. Both oxygene and nitrogene are attracted from the nitrous gas by the hydrogene, in such proportions as to form water and ammoniac, whilst the remaining oxygene and nitrogene[142] assume the form of nitrous oxide.

[142] The decomposition and recomposition of water, in this process, are analogous to some of the phænomena observed by the ingenious Mrs. Fulhame.

_c._ Nitrous gas placed in contact with bodies, such as iron and zinc decomposing water, is converted into nitrous oxide, at the same time that ammoniac is formed. It is difficult to ascertain the exact rationale of this process. For either the nascent hydrogene produced by the decomposition of the water by the metallic substance may combine with portions of both the oxygene and nitrogene of the nitrous gas; and thus by forming water and ammoniac, convert it into nitrous oxide. Or the metallic substance may attract at the same time oxygene from the water and nitrous gas, whilst the nascent hydrogene of the water seizes upon a portion of the nitrogene of the nitrous gas to form ammoniac.

The degree of diminution, and the analogy between this process and the decomposition of nitrous gas by sulphurated hydrogene, render the first opinion most probable.

VIII. _The production of Nitrous Oxide during the oxydation of Tin, Zinc, and Iron, in Nitric Acid._

_a._ Dr. Priestley discovered, that during the solution of tin, zinc, and iron, in nitric acid, certain portions of nitrous oxide were produced, mingled with quantities of nitrous gas, and nitrogene, varying in proportion as the acid employed was more or less concentrated.

It has long been known that ammoniac is formed during the solution of tin, zinc, and iron, in diluted nitric acid. Consequently, in these processes water is decomposed.

I had designed to investigate minutely these phænomena, so as to ascertain the quantities of water and acid decompounded, and of the new products generated. But after going through some experiments on the oxydation of tin without gaining conclusive results, the labor, and sacrifice of time they demanded, obliged me to desist from pursuing the subject, till I had completed more important investigations.

I shall detail the few observations which have occurred to me, relating to the production of nitrous oxide from metallic solutions.

_b._ When tin is dissolved in concentrated nitric acid, such as of 1.4, nitrous oxide is produced, mingled with generally more than twice its bulk of nitrous gas. In this process but little free nitrogene is evolved, and the tin is chiefly precipitated in the form of a white powder. If the solution, after the generation of these products, is saturated with lime, and heated, the ammoniacal smell is distinct.

When nitric acid of specific gravity 1.24, is made to act upon tin; in the beginning of the process, nearly equal parts of nitrous gas and nitrous oxide are produced; as it advances, the proportion of nitrous oxide to the nitrous gas increases: the largest quantity of nitrous oxide that I have found in the gas procured from tin is ¾, the remainder being nitrous gas and nitrogene.

When tin is oxydated in an acid of less specific gravity than 1.09, the quantities of gas disengaged are very small, and consist of nitrogene, mingled with minute portions of nitrous oxide, and nitrous gas.

Whenever I have saturated solutions of tin in nitric acid of different specific gravities, with lime, and afterwards heated them, the ammoniacal smell has been uniformly perceptible, and generally most distinct when diluted acids have been employed.

_c._ When zinc is dissolved in nitric acid, whatever is its specific gravity, certain quantities of nitrous oxide are produced.

Nitric acids of greater specific gravity than 1.2, act upon zinc with great rapidity, and great increase of temperature. The gases disengaged from these solutions consist of nitrous gas, nitrous oxide, and nitrogene; the nitrous oxide rarely equals one third of the whole.

When nitric acid of 1,104 is made to dissolve zinc, the gas obtained in the middle of the process consists chiefly of nitrous oxide. From such a solution I obtained gas which gave a residuum of one sixth only when absorbed by water. The taper burnt in it with a brilliant flame, and sulphur with a vivid rose-colored light.

100 grains of granulated zinc, during their solution in 300 grains of nitric acid, of 1,43, diluted with 14 times its weight of water, produced 26 cubic inches of gas. Of this gas ⁷/₃₆ were nitrous, ¹⁷/₃₆36 nitrous oxide, and the remainder nitrogene. The solution saturated with lime and heated, gave a distinct smell of ammoniac.

_d._ During the solution of iron in concentrated nitric acid, the gas given out is chiefly nitrous; it is however generally mingled with minute quantities of nitrous oxide. When very dilute nitric acids are made to act upon iron, by the assistance of heat, nitrous oxide is produced in considerable quantities, mingled with nitrous gas and nitrogene; the proportions of which are smaller as the process advances.[143] The fluid remaining after the oxydation and solution of iron in nitric acid, always contains ammoniac.

[143] From one of Dr. Priestley’s experiments, it appears that hydrogene gas is sometimes disengaged during the solution of iron in very dilute nitric acid by heat. This phænomenon has never occurred to me.

_e._ As during the solution of tin, zinc, and iron, in nitric acid, the quantity of acid is diminished in proportion as the process advances, it is reasonable to suppose that the relative quantities of the gases evolved are perpetually varying. In the beginning of a dissolution, the nitrous gas generally predominates, in the middle nitrous oxide, and at the end nitrogene.

_f._ During the generation of nitrous gas, nitrous oxide, and ammoniac, from the decomposition of solution of nitric acid in water, by tin, zinc, and iron, very complex attractions must exist between the constituents of the substances employed. The acid and the water are decomposed at the same time, and in proportions different as the solution is more concentrated, by the combination of their oxygene with the metallic body.

The nitrous gas is produced by the combination of the metal with ³²/₁₀₀ of the oxygene of the acid. The nitrous oxide is most probably generated by the decomposition of a portion of the nitrous gas disengaged, by the nascent hydrogene of the water decompounded; some of it may be possibly formed from a more complete decomposition of the acid.

The production of ammoniac may arise, probably from two causes; from the decomposition of the nitrous gas by the combination of the nascent hydrogene of the water, with portions of its oxygene and nitrogene at the same time; and from the union of hydrogene with nascent nitrogene liberated in consequence of a complete decomposition of part of the acid.

IX. _Additional Observations on the production of Nitrous Oxide._

_a._ When nitric acid is combined with muriatic acid, or sulphuric acid,[144] the quantities of nitrous oxide produced from its decomposition by tin, zinc, and iron, are rather increased than diminished. The nitrous oxide obtained from these solutions is, however, never sufficiently pure for physiological experiments. It is always mingled with either nitrous gas, nitrogene, or hydrogene, and sometimes with all of them.

[144] As was discovered by Priestley, and the Dutch Chemists.

_b._ From the solutions of bismuth, nickel, lead, and copper, in diluted nitric acid, I have never obtained any perceptible quantity of nitrous oxide: the gas produced is nitrous, mingled with different portions of nitrogene. Antimony and mercury, during their solution in aqua regia, give out only nitrous gas.

Probably none of the metallic bodies, except those that decompose water at temperatures below ignition, will generate nitrous oxide from nitric acid. On cobalt and manganese I have never had an opportunity of experimenting: manganese will probably produce nitrous oxide.

_c._ During the solution of vegetable matters[145] in nitric acid, by heat, very minute portions of nitrous oxide are sometimes produced, always however mingled with large quantities of nitrous gas, and carbonic acid.

[145] Such as the leaves, bark, and wood, of trees.

When nitric acid is decompounded by ether, fixed oils, volatile oils, or alcohol, towards the end of the process small quantities of nitrous oxide are produced, and sometimes sufficiently pure to support the flame of the taper.[146]

_d._ When green oxide of iron is dissolved in nitric acid, nitrous oxide is produced, mingled with nitrogene and nitrous gas.

_e._ During the conversion of green sulphate, or green muriate of iron into red, by the decomposition of dilute nitric acid, nitrous oxide is formed, mingled with different proportions of nitrous gas and nitrogene.

_f._ When solution of green nitrate of iron is heated, a part of the acid is decomposed, red oxide is precipitated, red nitrate formed, and impure nitrous oxide evolved.

_g._ When iron is introduced into a solution of nitrate of copper, the copper is precipitated in its metallic state, whilst nitrous oxide, mingled with small portions of nitrogene, is produced.[147]

[146] As I have observed after Priestley.

[147] As was discovered by Priestly.

Both zinc and tin precipitate copper in its metallic form from solution in the nitric acid. During these precipitations, certain quantities of nitrous oxide are generated, mingled however with larger quantities of nitrogene than that produced from decomposition by iron. In all these processes ammoniac is formed, and water consequently decomposed.

The decomposition of water and nitric acid, during the precipitation of copper from solution of nitrate of copper, by tin, zinc, and iron, depends upon the strong affinity of those metals for oxygene, and their powers of combining with a larger quantity of it than copper.

X. _Decomposition of Aqua Regia by Platina, and evolution of a Gas analogous to Oxygenated Muriatic Acid, and Nitrogene._

_a._ De la Metherie, in his essay on different airs, has asserted that the gas produced by the solution of platina in nitro-muriatic acid, is identical with the dephlogisticated nitrous gas of Priestly. He calls it nitrous gas with excess of pure air, and affirms that it diminishes, both with nitrous gas and common air.

_b._ I introduced into a vessel containing 30 grains of platina, 2050 grains of aqua regia, composed of equal parts, by weight, of concentrated nitric acid of 1,43, and muriatic acid of 1,16. At the common temperature, that is, 49°, no action between the acid and platina appeared to take place. On the application of the heat of a spirit lamp, the solution gradually became yellow red, and gas was given out with rapidity. Some of this gas received in a jar filled with warm water, appeared of a bright yellow color. On agitation, the greater part of it was absorbed by the water, and the remainder extinguished flame. When it was received over mercury, it acted upon it with great rapidity, and formed on the surface a white crust.

As the process of solution advanced, the color of the acid changed to dark red, at the same time that the production of gas was much increased; more than 40 cubic inches were soon collected in the water apparatus.

Different portions of the gas were examined, it exhibited the following properties:

1. Its color was orange red,[148] and its smell exactly
resembled that of oxygenated muriatic acid.

2. When agitated in boiled water, it was rapidly absorbed,
leaving a residuum of rather more than one twelfth.

3. The taper burnt in it with increased brilliancy,
the flame being long, and deep red at the edges.

4. Iron introduced into it ignited, burnt with a dull
red light.

5. Green vegetables exposed to it were instantly
rendered white.

6. It underwent no diminution, mingled with
atmospheric air.

7. When mingled with nitrous gas, it gave dense red
vapor, and rapid diminution.

[148] This deep color depended, in some measure, upon the nitro-muriatic vapor suspended in it. I have since observed that it is more intense in proportion as the heat employed for the production of the gas has been stronger. The natural color of the peculiar gas is deep yellow.

_c._ From the exhibition of these properties, it was evident that the gas produced during the solution of platina in aqua regia, chiefly consisted of oxygenated muriatic acid, or of a gas highly analogous to it. It was, however, difficult to conceive how a body, by combining with a portion of the oxygene of nitro-muriatic acid, could produce from it oxygenated muriatic acid, apparently mingled with very small portions of any other gas.

_d._ To ascertain whether any permanent gas was produced during the ebullition of aqua regia, of the same composition as that used for the solution of the platina; I kept a large quantity of it boiling for some time, in communication with the water apparatus; the gas generated appeared to be wholly nitro-muriatic, and was absorbed as fast as produced, by the water.

_e._ To determine whether any nitrous oxide was mingled with the peculiar gas, as well as the nature and quantity of the unabsorbable gas, nitrous gas was gradually added to 21 cubic inches of the gas produced from a new solution, till the diminution was complete: the gas remaining equalled 2,3 cubic inches; it was unabsorbable by water, and extinguished flame.

In another experiment, when the last portions of gas from a solution were carefully received in water previously boiled, 12 cubic inches agitated in water left a residuum of 1.3; whilst the same quantity decomposed by nitrous gas, containing,02 nitrogene, left about 1.5.

Hence it appeared that the aëriform products of the solution consisted of the peculiar gas analogous to oxygenated muriatic acid, and of a small quantity of nitrogene.

_f._ Consequently a portion of the nitric acid of the aqua regia had been decomposed; but if it had given oxygene both to the platina and muriatic acid, the quantity of nitrogene evolved ought to have been much more considerable.

_g._ To ascertain if any water had been decomposed, and the nitrogene condensed in the solution by its hydrogene, to form ammoniac, I saturated a solution with lime, and heated it, but no ammoniacal smell was perceived.

_h._ To determine if any nitrogene had entered into chemical combination with muriatic acid and oxygene, so as to form an aëriform triple compound, analogous in its properties to oxygenated muriatic acid, I exposed some of the gas to mercury, expecting that this substance, by combining with its oxygene, would effect a complete decomposition; and this was actually the case: for the gas was at first rapidly diminished, and the mercury became oxydated; its volume, however, soon increased; and the residual gas appeared to be nitrous, mingled with much nitrogene. The exact proportions of each, from an accident, I could not determine.

This experiment was inconclusive, because the nitro-muriatic acid suspended in the peculiar gas, from which it can probably be never perfectly freed, acted in common with it upon the mercury, and produced nitrous gas: and this nitrous gas, at the moment of its production, formed nitrous acid by combining with the oxygene of the peculiar gas; and the nitrous acid generated[149] was again decomposed by the mercury; and hence nitrous gas evolved, and possibly some nitrogene.

[149] The decomposition of aëriform nitrous acid by mercury, was first noted by Priestley; vol. iii. pag. 101. This decomposition I have often had occasion to observe. In reading Humbolt’s paper on eudiometry, Annales de Chimie, xxviii, pag. 150, I was not a little surprised to find that he takes no notice of this fact. He seems to suppose that nitrous acid can remain aëriform, and even be condensed, in contact with mercury, without alteration. He says, “In mingling 100 parts of atmospheric air with 100 of nitrous air, the air immediately became red, but all the acid produced remained aëriform; and after eighteen hours some _drops_ only of acid were formed, which _swam_ upon the mercury.”

_i._ Peculiar circumstances prevented me at this time from completely investigating the subject. It remains doubtful whether the gas consists simply of highly oxygenated muriatic acid and nitrogene,[150] produced by the decomposition of nitric acid from the coalescing affinities of platina and muriatic acid for oxygene; or whether it is composed of a _peculiar_ gas, analogous to oxygenated muriatic acid, and nitrogene, generated from some unknown affinities.[151]

[150] Lavoisier has said concerning aqua regia, “In solutions of metals in this acid, as in all other acids, the metals are first oxydated, by attracting a part of the oxygene from the compound radical. This occasions the disengagement of a particular species of gas not hitherto described, which may be called nitro-muriatic gas. It has a very disagreeable smell, and is fatal to animal life when respired; it attacks iron, and causes it to rust; it is absorbed in considerable quantities by water.” Elem. Eng. 237.

[151] I have no doubt but that the gas procured from the solution of gold in aqua regia, is analogous to that produced from platina.

Some very uncommon circumstances are attendant on the solution of platina:

1st. The immense quantity of acid required for the solution of a minute quantity of platina.

2d. The great quantity of gas produced during the solution of this minute quantity.

3d. The intense red color of the solution, and its perfectly acid properties after it ceases to act upon the metal.

XI. _On the action of the Electric Spark on a mixture of Nitrogene and Nitrous Gas._

Thinking it possible that nitrous gas and nitrogene might be made to combine by the action of the electric spark, so as to form nitrous oxide, I introduced 20 grain measures of each of them into a small detonating tube, graduated to grains, standing over mercury, and containing a very small quantity of cabbage juice rendered green by an alkali. After electric sparks had been passed through the gases for an hour and half, they were diminished to about 32, and the cabbage juice was slightly reddened. On introducing about 10 measures of hydrogene, and passing the electric spark through the whole, no inflammation or diminution was perceptible. Hence the condensation most probably arose wholly from the formation of nitrous acid,[152] by the more intimate union of the oxygene of nitrous gas with some of its nitrogene, as in the experiments of Priestley.

[152] For if nitrous oxide had been formed, it would have been decomposed by the hydrogene.

As the nascent nitrogene, in the decomposition of nitrate of ammoniac, combines with a portion of oxygene and nitrogene, to form nitrous oxide; it is probable that nitrous oxide may be produced during the passage of nitrous gas and ammoniac through a heated tube.

XII. _General Remarks._

There are no reasons for supposing that nitrous oxide is formed in any of the processes of nature; and the nice equilibrium of affinity by which it is constituted, forbids us to hope for the power of composing it from its simple principles. We must be content to produce it, either directly or indirectly, from the decomposition of nitric acid. And as in the decomposition of nitrate of ammoniac, not only all the nitrogene of the nitric acid enters into the composition of the nitrous oxide produced, but likewise that of the ammoniac, this process is by far the cheapest, as well as the most expeditious. A mode of producing ammoniac at little expence, has been proposed by Mr. Watt. Condensed in the sulphuric acid, it can be easily made to combine with nitric acid, from the decomposition of nitre by double affinity. And thus, if the hopes which the experiments at the end of those researches induce us to indulge, do not prove fallacious, a substance which has been heretofore almost exclusively appropriated to the destruction of mankind, may become, in the hands of philosophy, a means of producing health and pleasurable sensation.

RESEARCH II.

INTO THE COMBINATIONS OF NITROUS OXIDE, AND ITS DECOMPOSITION BY COMBUSTIBLE BODIES.

DIVISION I.

_EXPERIMENTS and OBSERVATIONS on the COMBINATIONS of NITROUS OXIDE._

I. _Combination of Water with Nitrous Oxide._

_a._ The discoverer of nitrous oxide first observed its solubility in water; and it has since been noticed by different experimentalists.

Dr. Priestley found that water dissolved about one half of its bulk of nitrous oxide, and that at the temperature of ebullition, this substance was incapable of remaining in combination with it.[153]

[153] Experiments and observations, vol. ii. pag. 81.

_b._ I introduced to 9 cubic inches of pure water, i. e. water distilled under mercury, 7 cubic inches of nitrous oxide, which had been obtained over mercury, from the decomposition of nitrate of ammoniac, and in consequence was perfectly pure. After they had remained together for 11 hours, temperature being 46°, during which time they were frequently agitated, the gas remaining was 2,3; consequently 4,7 cubic inches had been absorbed. And then, 100 cubic inches, = 25300 grains of water, will absorb 54 cubic inches, = 27 grains, of nitrous oxide.

_c._ The taste of water impregnated with nitrous oxide, is distinctly sweetish; it is softer than common water, and, in my opinion, much more agreeable to the palate. It produces no alteration in vegetable blues, and effects no change of color in metallic solutions.

_d._ Thinking that water impregnated with nitrous oxide might probably produce some effects when taken into the stomach, by giving out its gas, I drank, in June, 1799, about 3 ounces of it, but without perceiving any effects.

A few days ago, considering this quantity as inadequate, I took at two draughts nearly a pint, fully saturated; and at this time Mr. Joseph Priestley drank the same quantity.

We neither of us perceived any remarkable effects.

Since that time I have drank near three pints of it in the course of a day. In this instance it appeared to act as a diuretic, and I imagined that it expedited digestion. As a matter of taste, I should always prefer it to common water.

_e._ Two cubic inches of pure water, that had been made to absorb about 1,1 cubic inches of nitrous oxide; when kept for some time in ebullition, and then rapidly cooled, produced nearly 1 of gas. Sulphur burnt in this gas with a vivid rose-colored flame.

In another experiment, in which the gas was expelled by heat from impregnated water, and absorbed again after much agitation on cooling; the residuum was hardly perceptible, and most likely depended upon some gas which had adhered to the mercury, and was liberated during the ebullition. Hence it appears that nitrous oxide is expelled unaltered from its aqueous solution by heat.

_f._ I have before mentioned, Division III, that nitrous oxide, during its combination with spring water, expels the common air dissolved in it. This common air generally amounts to one sixteenth, the volume of the water being unity. A correction on account of this circumstance must be made for the apparent deficiency of diminution, and for the common air mingled in consequence, with nitrous oxide during its absorption by common water.

_g._ Water impregnated with nitrous gas absorbed nitrous oxide; but the residual gas was much greater than that of common water, and gave red fumes with atmospheric air. Nitrous gas agitated for a long while over water highly impregnated with nitrous oxide, was not in the slightest degree diminished, in one experiment indeed it was rather increased; doubtless from the liberation of some nitrous oxide from the water by the agitation.

_h._ Nitrous oxide kept in contact with aqueous solution of sulphurated hydrogene and often agitated, was not in the slightest degree diminished.

Sulphurated hydrogene, introduced into a solution of nitrous oxide, was rapidly absorbed, and as the process advanced, the nitrous oxide was given out.

_i._ Water impregnated with carbonic acid, possessed no action upon nitrous oxide, and did not in the slightest degree absorb it. When carbonic acid was introduced to an aqueous solution of nitrous oxide; the aëriform acid was absorbed, and the nitrous oxide liberated.

_k._ From these observations it appears that nitrous oxide has less affinity for water, than even the weaker acids, sulphurated hydrogene and carbonic acid; as indeed one might have conjectured a priori from its degree of solubility: likewise that it has a stronger attraction for water than the gases not possessed of acid or alkaline properties; it expelling from water nitrous gas, oxygene, and common air; probably hydrocarbonate, hydrogene, and nitrogene.

II. _Combinations of Nitrous Oxide with Fluid Inflammable Bodies._

_a._ Vitriolic ether absorbs nitrous oxide in much larger quantities than water.

A cubic inch of ether, at temperature 52°, combined with a cubic inch and seven tenths of nitrous oxide.

Ether thus impregnated was not at all altered in its appearance; its smell was precisely the same, but the taste appeared less pungent, and more agreeable. Nitrous oxide is liberated unaltered from ether at a very low temperature, that is, at about the boiling point of this fluid.

For expelling nitrous oxide from impregnated ether, and for ascertaining in general the quantity of gases combined with fluids, I have lately made use of a very simple method, which it may not be amiss to describe.

The impregnated fluid is introduced into a small thin tube, graduated to,05 cubic inches, through mercury. The quantity of fluid should never equal more than a fifth or sixth of the capacity of the tube.

The lower part of the tube is adapted to an orifice in the shelf of the mercurial apparatus, so as to make an angle of about 40° with the surface of the mercury.

The flame of a small spirit lamp is then applied to that part of the tube containing the fluid; and after the expulsion of the gas from it, the heat is raised so as to drive out the fluid through the orifice of the tube. Thus the liberated gas is preserved in a state proper for accurate examination.

Impregnated ether, during its combination with water, gives out the greater part of its nitrous oxide. During the liberation of nitrous oxide from ether, by its combination with water, a very curious phænomenon takes place.

If the water employed is colored, so that it may be seen in a stratum distinct from the impregnated ether, at the point of contact a number of small spherules of fluid will be perceived, apparently repulsive both to water and ether; these spherules become gradually covered with minute globules of gas, and as this gas is liberated from their surfaces, they gradually disappear.

_b._ Alcohol dissolves considerable quantities of nitrous oxide.

2 cubic inches of alcohol, at 52°, combined with 2,4 cubic inches of nitrous oxide. The alcohol thus impregnated had a taste rather sweeter than before, but in other physical properties was not perceptibly altered.

Nitrous oxide is incapable of remaining in combination with this fluid at the temperature of ebullition; it is liberated from it unaltered by heat.

Impregnated alcohol, during its combination with water, gives out the greater part of its combined nitrous oxide: on mingling the two fluids together, at the point of contact the alcohol becomes covered with an infinite number of small globules of gas, which continue to be generated during the whole of the combination, and in passing through the fluid render it almost opaque.

_c._ The essential oils absorb nitrous oxide to a greater extent than either alcohol or ether.

,5 cubic inches of oil of carui combined with 1,2 cubic inches of nitrous oxide at 51°. The color of the oil thus impregnated was rather paler than before.

Nitrous oxide is expelled unaltered from impregnated oil of carui, by heat.

1 of oil of turpentine absorbed nearly 2 of nitrous oxide, at 57°. Its properties were not sensibly altered from this combination, and the gas was expelled from it undecompounded, by heat.

_d._ As well as the essential oils, the fixed oils dissolve nitrous oxide at low temperatures, whilst at high temperatures they do not remain in combination.

1 of olive oil absorbed, at 61°, 1,2 of nitrous oxide, but without undergoing any apparent physical change.

III. _Action of Fluid Acids on Nitrous Oxide._

_a._ Nitrous oxide exposed to concentrated sulphuric acid, undergoes no change, and suffers no diminution, that may not be accounted for from the abstraction of a portion of its water by the acid.

_b._ Nitrous oxide is scarcely at all soluble in nitrous acid, and exposed to that substance, undergoes no alteration.

_c._ Muriatic acid, of specific gravity 1,14 absorbs about a third of its bulk of nitrous oxide. It suffers no apparent change in its properties from being thus impregnated, and the gas is again given out from it on the application of heat.

_d._ Acetic acid absorbs nearly one third of its bulk of nitrous oxide.

_e._ Aqua regia, that is, the nitro-muriatic acid, absorbs a very minute portion of nitrous oxide.

_f._ Nitrous oxide was exposed to a new compound acid, consisting of oxygenated muriatic acid, and sulphuric acid, which I discovered in July, 1799, and of which an account will be shortly published; but it was neither absorbed or altered.

I have before mentioned that the aqueous solutions of sulphurated hydrogene and carbonic acid, neither dissolve or alter nitrous oxide.

IV. _Action of Saline Solutions, and other Substances, on Nitrous Oxide._

_a._ Nitrous oxide exposed to concentrated solution of green sulphate of iron, at 58°, underwent no perceptible diminution; not even after it had been suffered to remain in contact with it for half an hour.

_b._ It underwent diminution of nearly,2 when agitated in contact with a solution of red sulphate of iron, the volume of the solution being unity.

_c._ Solution of green sulphate of iron, fully impregnated with nitrous gas, did not in the slightest degree absorb nitrous oxide, and appeared to have no action upon it.

_d._ Solution of green muriate of iron, whether impregnated with nitrous gas, or unimpregnated, has no affinity for, or action upon, nitrous oxide.

_e._ Solution of red muriate of iron in alcohol, absorbed nearly one fifth of its bulk, of nitrous oxide.

_f._ Solution of prussiate of potash absorbed nearly one third of its volume, of nitrous oxide, which was again expelled from it by heat.

_g._ Solution of nitrate of copper appeared to have no affinity for nitrous oxide.

_h._ Concentrated solution of nitrate of ammoniac, at 58°, absorbed one eighth of its bulk of nitrous oxide.

_i._ Solutions of alkaline sulphures absorb nitrous oxide in quantities proportionable to the water they contain; it is expelled from them unaltered by heat. None of the hydro-sulphures dissolve more than half their bulk of nitrous oxide.

_k._ Concentrated solutions of the sulphites possess little or no action on nitrous oxide; diluted solutions absorb it in small quantities.

_l._ Concentrated solution of muriate of tin absorbs about one eighth of nitrous oxide; more dilute solutions absorb larger quantities.

From these observations we learn, that neutro-saline solutions in general, have very feeble attractions for nitrous oxide; and as solutions of green muriate, and sulphate of iron, whether free from nitrous gas, or impregnated with it, possess no action upon nitrous oxide, nitrous gas may be separated from this substance by those solutions with greater facility than nitrous oxide can be separated from nitrous gas, by water or alcohol.

Charcoal absorbs nitrous oxide as well as all other gases; and it is disengaged from it by heat.

I have as yet found no other solid body, not possessed of alkaline properties, capable of absorbing nitrous oxide in any state of existence.

The bodies possessing the strongest affinity for oxygene, the dry sulphites, muriate of tin, the common sulphures, white prussiate of potash, and green oxide of iron, do not in the slightest degree act on nitrous oxide at common temperatures.

V. _Action of different Gases on Nitrous Oxide._

_a._ 12 measures of muriatic acid gas were mingled with 7 measures of nitrous oxide at 56°. After remaining together for a minute, they filled a space equal to 19½ measures. When water was introduced to them, the muriatic acid was absorbed much more slowly than if it had been unmingled.

In another experiment, when the gases were saturated with water, 9 measures of each of them, when mingled and suffered to remain in contact for a quarter of an hour, filled a space nearly equal to 19; and after the muriatic acid had been absorbed by potash, the nitrous oxide remained unaltered in its properties.

From the expansion, it appears most probable that aëriform muriatic acid, and nitrous oxide, have a certain affinity for each other, and that they combine when mingled together; for in the last experiment, the increase of volume cannot be accounted for by supposing that nitrous oxide undergoes less change of volume than muriatic acid, by aëriform combination with water, and that the expansion depended upon the solution of some of its combined water by the muriatic acid. That muriatic acid and nitrous oxide have a slight affinity for each other, likewise appears from the absorption of nitrous oxide by aqueous solution of muriatic acid.

Thinking that nitrous oxide might attract muriatic acid from its solution in water, I exposed a minute quantity of fluid muriatic acid to nitrous oxide; but no alteration of volume took place in the gas.

_b._ 6 measures of nitrous oxide were mingled with 11 measures of sulphureous acid, saturated with water; after remaining at rest for six minutes, they filled a space nearly equal to 18 measures. Exposed to water, the sulphureous acid was absorbed, but not nearly so rapidly as when in a free state. Sulphur burnt with a vivid flame in the residual nitrous oxide. 7 measures of sulphureous acid were now mingled with 8 of nitrous oxide. They filled a space nearly equal to 15¾, and no farther expansion took place afterwards.

From these experiments it appears probable that sulphureous acid, and nitrous oxide, have some affinity for each other.

_c._ 11 measures of carbonic acid were mingled with 8 of nitrous oxide; they filled a space nearly equal to 19 measures. On exposing the mixture to caustic potash, the carbonic acid was absorbed, and the nitrous oxide remained pure. Hence it appears that carbonic acid and nitrous oxide do not combine with each other.

_d._ Oxygenated muriatic acid, and nitrous oxide, were mingled in a water apparatus: there was a slight appearance of condensation; but this was most probably owing to absorption by the water; on agitation, the oxygenated muriatic acid was absorbed, and the greater part of the nitrous oxide remained unaltered.

_e._ Sulphurated hydrogene and nitrous oxide, mingled together, neither expanded or contracted; exposed to solution of potash, the acid[154] only was absorbed.

[154] The experiments of Berthollet have clearly proved the perfect acidity of this substance.

_f._ 10 measures of nitrous gas were admitted to 12 of nitrous oxide at 59°. They filled a space equal to 22, and after remaining together for an hour, had undergone no change. Solution of muriate of iron absorbed the nitrous gas without affecting the nitrous oxide.

_g._ Nitrous oxide was successively mingled with oxygene, atmospheric air, hydrocarbonate, phosphorated hydrogene, hydrogene, and nitrogene, at 57°; it appeared to possess no action on any of them, and was separated by water, the gases remaining unaltered.

_h._ As nitrous oxide was soluble in ether, alcohol, and the other inflammable fluids, it was reasonable to suppose that its affinity for those bodies would enable them to unite with it in the aëriform state. At the suggestion of Dr. Beddoes I made the following experiment:

To 12 measures of nitrous oxide, at 54°, I introduced a single drop of ether; the gas immediately began to expand, and in four minutes filled a space equal to sixteen measures and a quarter. When an inflamed taper was plunged into the gas thus holding ether in solution, a light blue flame slowly passed through it.

A considerable diminution of temperature is most probably produced, from the great expansion of nitrous oxide during its combination with ether.

A drop of alcohol was admitted to 14 measures of nitrous oxide. In five minutes, the gas filled a space equal to fifteen and a third; but no farther diminution took place afterwards.

A minute quantity of oil of turpentine was introduced to 14 measures of nitrous oxide; it filled, in 4 minutes, a space rather less than 14; and no farther change took place afterwards. Most likely this contraction arose from the precipitation of the water dissolved in the gas by the stronger affinity of the oil for nitrous oxide. To ascertain with certainty if any oil had been dissolved by the gas, I introduced into it a small quantity of ammoniac. It immediately became slightly clouded, most probably from the formation of soap, by the combination of the dissolved oil with the ammoniac.

From these experiments we learn, that when nitrous oxide is mingled with either carbonic acid, oxygene, common air, hydrocarbonate, sulphurated hydrogene, hydrogene, or nitrogene, they may be separated from each other without making any allowance for contraction or expansion; but if a mixture of either muriatic acid, or sulphureous acid gas, with nitrous oxide, is experimented upon; in the absorption of the acid by alkalies, the apparent volume of gas condensed will be less than the real one, by a quantity equal to the sum of expansion from combination. Consequently a correction must be made on account of this circumstance.

Though alcohol, ether, essential oils, and the fluid inflammable bodies in general, dissolve nitrous oxide with much greater rapidity than water, yet as we are not perfectly acquainted with their action on unabsorbable gases, it is better to employ water for separating nitrous oxide from these substances; particularly as that fluid is more or less combined with all gases, and as we are acquainted with the extent of its action upon them.

By pursuing the subject of the solution of essential oils in gases, we may probably discover a mode of obtaining them in a state of absolute dryness. For if other gases as well as nitrous oxide, have a stronger affinity for oils than for water, water most probably will be precipitated from them during their solution of oils; and after their saturation with oil, it is likely that they are capable of being deprived of that substance by ammoniac.

VI. _Action of aëriform Nitrous Oxide in the Alkalies. History of the discovery of the combinations of Nitrous Oxide with the Alkalies._

_a._ When nitrous oxide in a free state is exposed to the solid caustic alkalies and alkaline earths, at common temperatures, it is neither absorbed nor acted upon; when it is placed in contact with solutions of them in water, a small quantity is dissolved; but this combination appears to depend on the water of the solution, for the gas can be expelled unaltered, at the temperature of ebullition.

_b._ Caustic potash was exposed to nitrous oxide for 13 hours: the diminution was not to one fiftieth, and this slight condensation most probably depended upon its combination with the water of the gas.

Concentrated solution of potash absorbed a fourth of its bulk of nitrous oxide. When the impregnated solution was heated, globules of gas were given out from it rapidly; but the quantity collected was too small to examine.

Soda, whether solid or in solution, exhibited exactly the same phænomena with nitrous oxide. The solution of soda absorbed near a quarter of its bulk of gas.

_c._ 11 measures of ammoniacal gas were mingled with 8 measures of nitrous oxide over dry mercury, both of the gases being saturated with water. No change of appearance was produced by the mixture, and they filled, after two minutes, a space equal to 19. On the introduction of a little water, the ammoniac was absorbed, and the nitrous oxide remained unaltered, for it was dissolved by water as rapidly as if it had never been mingled with ammoniac.[155]

[155] The Dutch chemists have asserted, that mixture with ammoniac prevents the absorption of nitrous oxide by water, either wholly or partially. Journal de Physique, t. xliii. part ii. pag. 327. It is difficult to account for their mistake.

7 measures of nitrous oxide, exposed to 6 measures of solution of ammoniac in water, was in an hour diminished to 4½ nearly. When the solution was heated over mercury, permanent gas was produced, which was unabsorbable by a minute quantity of water, and soluble in a large quantity; consequently it was nitrous oxide.

_d._ Nitrous oxide was exposed to dry caustic strontian; it underwent a diminution of nearly one fortieth, which most likely was owing to the combination of the strontian with its water.

11 measures of nitrous oxide were agitated in contact with 8 of strontian lime water: nearly 4 measures were absorbed. The impregnated solution exposed to heat, rapidly gave out its gas; 3 measures were soon collected, which mingled with a small quantity of hydrogene, and inflamed by the taper, gave a smart detonation.

_e._ Nitrous oxide exposed to lime and argil, both wet and dry, was not in the slightest degree acted upon.

From these experiments it is evident that nitrous oxide in the aëriform state cannot be combined either with the alkalies, or the alkaline earths. That a combination may be effected between nitrous oxide and these substances, it must be presented to them, in the _nascent state_.

The salts composed of the alkalies and nitrous oxide, are not analogous to any other compound substances, being possessed of very singular properties. Before these properties are detailed, it may not be amiss to give an account of the accidental way in which I discovered the mode of combination.

In December, 1799, designing to make a very delicate experiment, with a view to ascertain if any water was decomposed during the conversion of nitrous gas into nitrous oxide, by sulphite of potash, I exposed 200 grains of crystalised sulphite of potash, containing great superabundance of alkali, to 14 cubic inches of nitrous gas, containing one eighteenth nitrogene. The alkali was employed to preserve any ammoniac that might be formed, in the free state, as it would otherwise combine with sulphureous acid.[156]

[156] Sulphureous acid saturates more potash than sulphuric acid, so that most probably during the conversion of sulphite of potash into sulphate, portions of sulphureous acid are disengaged.

The volume of gas diminished with great rapidity; in two hours and ten minutes it was reduced to 6⁴/₅, which I considered as the limit of diminution. Accidentally, however, suffering it to remain for three hours longer, I was much surprised by finding that not quite 2 cubic inches remained, which consisted of nitrous oxide, mingled with the nitrogene that existed before the experiment.

In accounting theoretically for this phænomenon, different suppositions necessarily presented themselves.

1st, It was possible, that though sulphite of potash, and potash, separately possessed no action on free nitrous oxide, yet in combination they might exert such affinities upon it as either to absorb it, or make it enter into new combinations.

2dly. It was more probable that the caustic potash, though incapable of condensing aëriform nitrous oxide, was yet possessed of a strong affinity for it when in the _nascent state_, and that the nitrous oxide condensed in the experiment had been combined in this state with the free alkali.

To ascertain if the compound of potash and sulphite of potash with sulphate, was capable of acting upon nitrous oxide, I suffered a quantity of this substance to remain in contact with the gas for near a day: no change whatever took place.

To determine whether the diminution of nitrous oxide depended upon its absorption in the nascent state, by the peculiar compound of potash and sulphite of potash, or if it was simply owing to the alkali.

I mingled a solution of sulphite of potash with caustic soda; the salt, after being evaporated at a low temperature, was exposed to nitrous gas. The nitrous oxide formed was absorbed, but in rather less quantities than when alkaline sulphite of potash was employed.

Hence it was evident that the alkali was the agent that had condensed the nitrous oxide in those experiments, for soda is incapable of combining either with sulphate, or sulphite of potash.

To ascertain whether any change in the constitution of the nitrous oxide had been produced by the condensation, I introduced a small quantity of sulphite of potash, with excess of alkali, that had absorbed nitrous oxide, into a long and thin cylindrical tube filled with mercury; and inclining it at an angle of 35° with the plane of the mercury, applied the heat of a spirit lamp to that part of the tube containing the salts; when the glass became very hot, gas was given out with rapidity; in less than a minute the tube was full. This gas was transfered into another tube, and examined; it proved to be nitrous oxide in its highest state of purity;[157] for a portion of it absorbed by common water, left no more than a residuum of ¹/₁₅, and sulphur burnt in it with a vivid rose-colored flame.

[157] Hence we learn that sulphite of potash, when strongly heated, does not decompose nitrous oxide, even in the _nascent state_.

Being now satisfied that the alkalies were capable of combining with nitrous oxide; to investigate with precision the nature of these new compounds, I proceeded in the following manner.

VII. _Combination of Nitrous Oxide with Potash._

_a._ Into a solution of sulphite of potash, which had been made by passing sulphureous acid gas from a mercurial airholder into caustic potash dissolved in water, I introduced 17 grains of dry potash. The whole evaporated at a low temperature, gave 143 grains of salt. This salt was not _wholly_ composed of sulphite of potash and potash; it contained as well, a minute quantity of carbonate, and sulphate of potash, formed during the evaporation.[158]

[158] See the excellent memoir of Fourcroy and Vauquelin on the sulphureous acid, and its combinations. Annales de Chimie, ii, 54. Or Nicholson’s Phil. Journal, vol. i, pag. 313.

120 grains of it finely pulverised, and retaining the water of crystalisation, were exposed to 15 cubic inches of nitrous gas, over mercury. The nitrous gas diminished with great rapidity, and in three hours a cubic inch and nine tenths only remained, which consisted of nearly one third nitrous oxide, and two thirds nitrogene that had pre-existed in the nitrous gas. The increase of weight of the salt could not be determined, as some of it was lost by adhering to the vessel in which the combination was effected, and to the mercury. It presented no distinct series of crystalisations, even when examined by the magnifier; rendered green vegetable blues, and its taste was very different from that of the remaining quantity of salt that had been exposed to the atmosphere. A portion of it strongly heated over mercury, gave out gas with great rapidity, which had all the properties of the purest nitrous oxide.

When water was poured upon some of it, no gas was given out, and the whole was equably and gradually dissolved. Alcohol, as well as ether, appeared incapable of dissolving any part of it.

When muriatic acid was introduced into it, confined by mercury, a rapid effervescence took place. Part of the gas disengaged was sulphureous acid, and carbonic acid; the remainder was nitrous oxide.

_b._ I made a number of experiments upon salts procured in the manner I have just described, with a view to obtain the compound of nitrous oxide and potash, free from admixture of other salts.

When the mixed salt was boiled in alcohol or ether, no part of it appeared to be dissolved. Finding that little or no gas was given out during the ebullition of concentrated solutions of the mixed salts, I attempted to separate the sulphate, sulphite, and carbonate of potash, from the combination of nitrous oxide and potash, by successive evaporations and crystalisations. But though in this way it was nearly freed from sulphate of potash, yet the extreme and nearly equal solubility of the other salts, prevented me from completely separating them from each other.

By exposing, however, very finely pulverised sulphite of potash, mingled with alkali, for a great length of time to nitrous gas, it was almost wholly converted into sulphate; and after the separation of this solution, evaporation, and crystalisation, at a low temperature, I obtained the new combination, mingled with very little carbonate of potash, and still less of sulphite.

The minute quantity of sulphite chiefly appeared in very small crystals; distinct from the mass of salt, which possessed no regular crystalisation, and was almost wholly composed of the new compound, intimated mingled with a little carbonate. The new compound, as nearly as I could estimate from the quantity of nitrous oxide absorbed, consisted of about 3 alkali, to 1 of nitrous oxide, by weight.

It exhibited the following properties:

1. Its taste was caustic, and possessed of a pungency different from either potash or carbonate of potash.

2. It rendered vegetable blues green, which might possibly depend upon the carbonate of potash mixed with it.

3. Pulverised charcoal mingled with a few grains of it, and inflamed, burnt with flight scintillations. Projected into zinc in a state of fusion, a slight inflammation was produced.

4. When either sulphuric, muriatic, or nitric acid was introduced to it under mercury, it gave out nitrous oxide, mingled with a little carbonic acid.

5. Thrown into a solution of sulphurated hydrogene, gas was disengaged from it, but in quantities too minute to be examined.

6. When carbonic acid was thrown into a solution of it in water, gas was disengaged; on examination it proved to be nitrous oxide.