Part 14

The 16 measures remaining underwent no perceptible diminution with nitrous gas; the taper plunged into them was instantly extinguished.

To ascertain if the phosphoric acid produced in the experiments made under mercury did not in some measure prevent the decomposition of the whole of the nitrous oxide by the phosphorus, I introduced into a mixture of 5 nitrogene and 1 nitrous oxide, ignited phosphorus: but it was immediately extinguished.[174]

The Dutch Chemists found that phosphorus might be fused in nitrous oxide without being luminous. They assert that phosphorus in a state of inflammation, introduced into this gas, was immediately extinguished; though when taken out into the atmosphere, it again burnt of its own accord.[175] It is difficult to account for their mistake.

[174] Phosphorus burnt feebly with a white flame in a mixture of 4 nitrogene and 1 nitrous oxide.

[175] Journal de Physique, xliii. 328.

V. _Decomposition of Nitrous Oxide by Phosphorated Hydrogene._

_a._ It has been mentioned in Res. II. Div. I. that phosphorated hydrogene and nitrous oxide posses no action on each other, at atmospheric temperatures.

Phosphorated hydrogene mingled with nitrous oxide, is capable of being inflamed by the electric spark, or by ignition.

_b. E._ 1. 10 grain measures of phosphorated hydrogene, carefully produced by means of phosphorus and solution of caustic alkali, were mingled with 52 measures of nitrous oxide. The electric spark passed through them, produced a vivid inflammation. The elastic products were clouded with dense white vapor, and after some minutes filled a space nearly equal to 60. On the introduction of water, no absorption took place. When 43 of nitrous gas were admitted, the whole diminished to 70.

_E._ 2. 25 of nitrous oxide were fired with 10 of phosphorated hydrogene, by the electric spark. After detonation[176] they filled a space exactly equal to 25. On the admission of solution of green sulphate of iron, and prussiate of potash, no blue or green precipitate was produced. On the introduction of water, no diminution was perceived. 25 of nitrous gas mingled with them, gave exactly 50.

[176] In this experiment, as in the last, dense white vapor was produced.

_E._ 3. 10 of nitrous oxide, mingled with 20 of phosphorated hydrogene, could not be inflamed.

25 of nitrous oxide, with 20 phosphorated hydrogene, inflamed. The gas after detonation, was rendered opaque by dense white vapor, and filled a space nearly equal to 45. No absorption took place when water was introduced. On admitting a little oxygene no white fumes, or diminution, was perceived. The electric spark passed through the mixture, produced an explosion, with great diminution.

_c._ From _E._ 1 it appears, that when a small quantity of phosphorated hydrogene is inflamed with nitrous oxide, both the phosphorus and hydrogene are consumed; whilst the superabundant nitrous oxide, is converted into nitrous acid and atmospheric air, by the ignition; or a certain quantity is partially decomposed into atmospheric air by the combination of a portion of its oxygene with the combustible gas.

From _E._ 2 we learn, that when the phosphorated hydrogene and nitrous oxide are to each other as 25 to 10 nearly, they both disappear, whilst nitrogene is evolved, and water and phosphoric acid produced. Reasoning concerning the composition of nitrous oxide from this experiment, we should conclude that it was composed of about 38 oxygene, and 62 nitrogene.

The result of _E._ 3 is interesting; we are taught from it that the affinity of phosphorus for the oxygene of nitrous oxide is stronger than that of hydrogene, at the temperature of ignition; so that when phosphorated hydrogene is mingled with a quantity of nitrous oxide, not containing sufficient oxygene to burn both its constituent parts, the phosphorus only is consumed, whilst the hydrogene is liberated.

In repeating the experiments with phosphorated hydrogene that had remained for some hours in the mercurial apparatus, I did not gain exactly the same results; for a larger quantity of it was required to decompose the nitrous oxide, than in the former experiments; doubtless from its having deposited a portion of its phosphorus. They confirm, however, the above mentioned conclusions.

In the course of experimenting, I passed the electric spark, for a quarter of an hour, through about 60 measures of phosphorated hydrogene. It underwent no alteration of volume. Phosphorus was apparently precipitated from it, and it had wholly lost its power of inflaming, in contact with common air.

VI. _Decomposition of Nitrous Oxide by Sulphur._

From the phænomena before mentioned,[177] relating to the combustion of sulphur in nitrous oxide, it was evident that this gas was only decomposable by it, at a much higher temperature than common air.

[177] Res. I. Div. III. S. II.

I introduced into sulphur in contact with nitrous oxide, over mercury heated to 112°-114°, a wire intensely ignited. It lost much of its heat in passing through the mercury, but still appeared red in the vessel. The sulphur rapidly fused, and sublimed without being at all luminous. This experiment was repeated five or six times, but in no instance could the combustion of sulphur, by means of the ignited wire, be effected.

I inflamed sulphur in nitrous oxide in the same manner as phosphorus; namely, by introducing it into the small vessel filled with oxygene, and igniting it by means of the heated wire. In these experiments the sulphur burnt with a vivid rose-colored light, and much sulphuric, with a little sulphureous acid, was formed.

Experimenting in this way I was never, however, able to decompose more than one third of the quantity of nitrous oxide employed; not only the nitrogene evolved, but likewise the sulphuric and sulphureous acids produced, stopping the combustion.

I found that sulphur in a state of vivid inflammation, when introduced into a mixture of one fourth nitrogene, and three fourths nitrous oxide, burnt with a flame very much enlarged, and of a vivid rose color. In one third nitrogene, and two thirds nitrous oxide, it burnt feebly with a yellow flame. In equal parts of nitrous oxide and nitrogene, it was instantly extinguished.

Sulphur burnt feebly, with a light yellow flame, when introduced ignited into a mixture of 5 nitrous gas, and 6 nitrous oxide. In one third nitrous oxide, and two thirds nitrous gas, it was instantly extinguished. From many circumstances, I am inclined to believe that sulphur is incapable, at any temperature, of slowly decomposing nitrous oxide, so as to burn in it with a blue flame, forming sulphureous acid alone. It appears to attract oxygene from it only when intensely ignited, so as to form chiefly sulphuric acid, and that with great rapidity, and vivid inflammation.

VII. _Decomposition of Nitrous Oxide by Sulphurated Hydrogene._

_a._ Though nitrous oxide and sulphurated hydrogene do not act upon each other at common temperatures, yet they undergo a mutual decomposition when mingled together in certain proportions, and ignited by the electric spark.

From more than twenty experiments made on the inflammation of sulphurated hydrogene in nitrous oxide, I select the following as the most conclusive and accurate. The temperature at which they were made was from 41° to 49°.

_b._ _E._ 1. About 35 measures of nitrous oxide were fired with 10 of sulphurated hydrogene; the expansion during inflammation was very great, and the flame sky-blue. Immediately after, the gases filled a space equal to 48 nearly. White fumes were then formed, and they gradually contracted to 40. On the admission of a little strontian lime water, a slight absorption took place, with white precipitation; and the volume occupied by the residual gas nearly equalled 37. On admitting nitrous gas to these, no perceptible diminution took place.

_E._ 2. 20 sulphurated hydrogene, with 25 nitrous oxide, could not be inflamed.

30 nitrous oxide, with 22 sulphurated hydrogene, could not be inflamed.

35 nitrous oxide, with 20 sulphurated hydrogene, inflamed with vivid blue light, and great expansion. After the explosion, the gases filled exactly the same space as before the experiment; no white fumes were perceived, and no farther contraction occurred. On the addition of strontian lime water, a copious precipitation, with diminution, took place; and the residual gas filled a space nearly equal to 35½.

_E._ 3. 47 nitrous oxide, and 14 sulphurated hydrogene, inflamed. After the explosion, the gases filled a space nearly equal to 65; then white fumes formed, and they gradually diminished to 52. On the introduction of muriate of strontian, a copious white precipitate was produced; and on the addition of water, no further absorption took place. To the residual 52, about 20 of nitrous gas were added; they filled together a space equal to about 67.

_c._ In none of the experiments made on the inflammation of sulphurated hydrogene and nitrous oxide, could I ascertain with certainty the precipitation of sulphur. In one or two processes the detonating tube was rendered a little white at the points of contact with the mercury; but this was most probably owing to the oxydation of the mercury, either by the heated sulphuric acid formed, or from nitrous acid produced by the ignition. The presence of nitrous acid I could not ascertain in these processes by my usual tests, because the combustion of sulphur over white prussiate of iron, converts it into light green.

When I introduced an inflamed taper into about 3 parts of sulphurated hydrogene, and 2 parts of nitrous oxide, in which proportions they could not have been fired by the electric spark, a blue flame passed through them, and much sulphur was deposited on the sides of the vessel. But this sulphur most probably owed its formation to the decomposition of a portion of sulphurated hydrogene not burnt, by the sulphureous acid formed from the combustion of the other portion.

We may then conclude with probability, that sulphurated hydrogene and nitrous oxide will not decompose each other, when acted on by the electric spark, unless their proportions are such as to enable the whole of the sulphurated hydrogene to be decomposed, so that both of its constituents may become oxygenated, by attracting oxygene from the nitrous oxide: likewise, that when the sulphurated hydrogene is at its _maximum_ of inflammation, the hydrogene and sulphur form with the whole of the oxygene of nitrous oxide, water and sulphureous acid; _E._ 2: whereas at its _minimum_ they produce water, and chiefly, _perhaps_ wholly, sulphuric acid; at the same time that the nitrous oxide partially decomposed, is converted into nitrogene, and a gas analogous to atmospheric air, or into nitrogene, nitrous acid, and atmospheric air. _E._ 1. _E._ 3.

By pursuing those experiments, and using larger quantities of gas, we may probably be able to ascertain from them with accuracy, the composition of sulphuric and sulphureous acids.

I own I was disappointed in the results, for I expected to have been able to ascertain from them, the relative affinities of sulphur, and hydrogene for the oxygene of nitrous oxide, at the temperature of ignition. I conjectured that nitrous oxide, mingled with excess of sulphurated hydrogene, would have been decomposed, and one of the principles of it evolved unaltered, as was the case with phosphorated hydrogene.

If we estimate the composition of nitrous oxide from the quantity of nitrogene produced in _E._ 2, it is composed of about 61 nitrogene, and 39 oxygene.

VIII. _Decomposition of Nitrous Oxide by Charcoal._

An account of the analysis of nitrous oxide by charcoal is given in Res. I. Div. III. I have lately made two experiments on the combustion of charcoal in nitrous oxide, in which every precaution was taken to prevent the existence of sources of error. Of one of these I shall give a detail.

_E._ Temperature being 51°, about a grain of charcoal, which had been exposed for some hours to a red heat, was introduced whilst ignited, under mercury, and transferred into a graduated jar, containing 3 cubic inches of pure nitrous oxide, standing over dry mercury.

The focus of a burning lens was thrown on the charcoal; it instantly inflamed, and burnt with great vividness for near a minute, the gas being much expanded. The focus was continually applied to it for ten minutes, when the process appeared at an end. The gases, when the common temperature and pressure were restored, filled a space equal to 4,2 cubic inches.

On introducing into them a few grain measures of solution of green muriate of iron, for the double purpose of saturating them with moisture, and ascertaining if any nitrous acid had been formed, no change of volume took place; and prussiate of potash gave with the muriate a white precipitate only.

On the admission of a small quantity of concentrated solution of caustic potash, a diminution of the gas slowly took place; when it was complete the volume equalled about 3.05 cubic inches. By agitation in well boiled water, about,9 of these were absorbed; the remainder appeared to be pure nitrogene.

The difference between the estimation founded upon the nitrogene evolved, and that deduced from the carbonic acid generated in this experiment, is not nearly so great as in that Res. I. Div. III. Taking about the mean proportions, we should conclude that nitrous oxide was composed of about 38 oxygene, and 62 nitrogene.

Charcoal burnt with greater vividness than in common air, in a mixture of one third nitrogene and two thirds nitrous oxide. In equal parts of nitrous oxide and nitrogene, its light was barely perceptible. In one third nitrous oxide, and two thirds nitrogene, it was almost immediately extinguished.

As charcoal burns vividly in nitrous gas, when it has been previously ignited to whiteness, I introduced it into a mixture of equal parts of nitrous oxide and nitrous gas; it burnt with a deep and bright red.

IX. _Decomposition of Nitrous Oxide by Hydrocarbonate._

Nitrous oxide, and hydrocarbonate, possess no action on each other, except at high temperatures. When mingled in certain proportions, and exposed to the electric shock, a new arrangement of their principles takes place.

_E._ 1. Temperature being 53°, 35 of nitrous oxide, mingled with 15 of hydrocarbonate, were fired by the electric spark; the inflammation was very vivid, and the light produced, bright red. After the explosion, the space occupied by the gases equalled about 60. On the admission of solution of strontian, a copious white precipitate was produced, and the gas diminished by agitation, to rather more than 35. When 36 of nitrous gas were added to these, white fumes appeared and the whole diminished to 62. When a little muriatic acid was poured on the white precipitate from the solution of strontian, gas was evolved from it, and it was gradually dissolved.

_E._ 2. 22 nitrous oxide were inflamed with 20 hydrocarbonate; after the explosion, they filled a space equal to 45; when strontian lime water was introduced, white precipitation took place, and the diminution was to 31.

To these 31, 14 of nitrous oxide were admitted, and the electric spark passed through them; an inflammation took place: carbonic acid was formed, after the absorption of which, the gas remaining filled a space equal to 43, and did not diminish with nitrous gas.

The hydrocarbonate employed in these experiments, was procured from alcohol by means of sulphuric acid. In another set of experiments made with less accuracy, the same general results were obtained. Whenever hydrocarbonate inflamed with nitrous oxide, both its constituents were oxygenated; in all cases carbonic acid was formed, and in no instance free hydrogene evolved, or charcoal precipitated.

In the decomposition of nitrous oxide by hydrocarbonate, the residual nitrogene is less than in other combustions. This circumstance I am unable to explain.

Reasoning from analogy, there can be little doubt, but that when hydrocarbonate is inflamed with excess of nitrous oxide, it will be only partially decompounded, or converted into nitrogene, nitrous acid, and atmospheric air.

The Dutch Chemists have asserted, that charcoal does not burn in nitrous oxide, except in consequence of the previous decomposition of the gas by the hydrogene always contained in this substance; and likewise, that when hydrocarbonate and nitrous oxide were mingled together, and fired by the electric spark, the hydrogene only was burnt, whilst the charcoal was precipitated.

It is difficult to account for these numerous mistakes. Their theory of the _non-respirability_ of nitrous oxide was founded upon them. They supposed that the chief use of respiration was to deprive the blood of its superabundant carbon, by the combination of atmospheric oxygene with that principle; and that nitrous oxide was highly fatal to life, because it was incapable of de-carbonating the blood[178]!!

[178] Journal de Physique, xliii. 334.

X. _Combustion of Iron in Nitrous Oxide._

I introduced into a jar of the capacity of 20 cubic inches, containing 11 cubic inches of nitrous oxide, over mercury, a small quantity of fine iron wire twisted together, and having affixed to it a particle of cork. On throwing the focus of a burning glass on the cork, it instantly inflamed, and the fire was communicated to the wire, which burnt with great vividness for some moments, projecting brilliant white sparks. After it had ceased to burn the gas was increased in volume rather more than three tenths of an inch. The nitrous acid tests were introduced, but no acid appeared to have been formed. On exposing the gas to water, near 4,2 cubic inches were absorbed: the 7,1 remaining appeared to be pure nitrogene.

From this experiment it is evident that iron at the temperature of ignition, is capable of decomposing nitrous oxide; likewise that it is incapable of burning in it when it contains more than three fifths nitrogene.

I attempted to inflame zinc in nitrous oxide, in the same way as iron; but without success. By keeping the focus of a burning glass upon some zinc filings, in a small quantity of nitrous oxide, I converted a little of the zinc into white oxide, and consequently decomposed a portion of the gas.

XI. _Combustion of Pyrophorus in Nitrous Oxide._

Pyrophorus, which inflames in nitrous gas, and atmospheric air, at or even below 40°, requires for its combustion in nitrous oxide a much higher temperature. It will not burn in it, or alter it, even at 212°.

I have often inflamed pyrophorus in nitrous oxide over mercury, by means of a wire strongly heated, but not ignited. The light produced by the ignition of pyrophorus in nitrous oxide is white, like that produced by it in oxygene: in nitrous gas it is red.

When pyrophorus burns out in nitrous oxide, a little increase of the volume of gas is produced. Strontian lime water agitated in this gas becomes clouded; but the quantity of carbonic acid formed is extremely minute. I have never made any delicate experiments on the combustion of pyrophorus in nitrous oxide.

XII. _Combustion of the Taper in Nitrous Oxide._

It has been noticed by different experimentalists, that the taper burns with a flame considerably enlarged in nitrous oxide: sometimes with a vivid light and crackling noise, as in oxygene; at other times with a white central flame, surrounded by a feeble blue one.

My experiments on the combustion of the taper in nitrous oxide, were chiefly made with a view to ascertain the cause of the double flame.

When the inflamed taper is introduced into pure nitrous oxide, it burns at first with a brilliant white light, and sparkles as in oxygene. As the combustion goes on, the brilliancy of the flame diminishes; it gradually lengthens, and becomes surrounded with a pale blue cone of light, from the apex of which much unburnt charcoal is thrown off, in the form of smoke. The flame continues double to the end of the process.

When the residual gases are examined after combustion, much nitrous acid is found suspended in them; and they are composed of carbonic acid, nitrogene, and about one fourth of undecompounded nitrous oxide.

The double flame depends upon the nitrous acid formed by the ignition; for it can be produced by plunging the taper into common air containing nitrous acid vapor, or into a mixture of nitrous oxide and nitrogene, through which nitrous acid has been diffused. It is never perceived in the combustion of the taper, till much nitrous acid is formed.

In attempting to respire some residual gas of nitrous oxide, in which a taper had burnt out, I found it so highly impregnated with nitrous acid, as to disable me from even taking it into my mouth.

The taper burns in a mixture of equal parts nitrous oxide and nitrogene, at first with a flame nearly the same as that of a candle in common air; white. Before its extinction the interior white flame, and exterior blue flame, are perceived.

The taper is instantly extinguished in a mixture of one fourth nitrous oxide, and three fourths nitrogene.

In a mixture of equal parts nitrous oxide and nitrous gas, the taper burns at first with nearly as much brilliancy as in pure nitrous oxide; gradually the double and feeble flame is produced.

XIII. _On the Combustion of different Compound Bodies in Nitrous Oxide._

All the solid and fluid compound inflammable bodies on which I have experimented, burn in nitrous oxide, at high temperatures. Wood, cotton, and paper, are easily inflamed in it by the burning glass. During their combustion, nitrous acid is always formed, carbonic acid, and water produced, and nitrogene evolved, rather less in bulk than the nitrous oxide decomposed.

I have already mentioned that alcohol and ether are soluble in nitrous oxide. When an ignited body is introduced into the solution of alcohol, or ether in nitrous oxide, a slight explosion takes place.

XIV. _General Conclusions relating to the Decomposition of Nitrous Oxide, and to its Analysis._

From what has been said in the preceding sections, it appears that the inflammable bodies, in general, require for their combustion in nitrous oxide, much higher temperatures than those at which they burn in atmospheric air, or oxygene.

When intensely heated they decompose it, with the production of much heat and light, and become oxygenated.

During the combustion of solid or fluid bodies, producing flame, in nitrous oxide, nitrous acid is generated, most probably from a new arrangement of principles, analogous to those observed in Sect. II, by the ignition of that part of the gas not in contact with the burning substance. Likewise when nitrous oxide in excess is decomcomposed by inflammable gases, nitrous acid, and sometimes a gas analogous to common air, is produced, doubtless from the same cause.

Pyrophorus is the only body that inflames in nitrous oxide, below the temperature of ignition.

Phosphorus burns in it with the blue flame, probably forming with its oxygene only phosphoreous acid at the dull red heat, and with the intensely vivid flame, producing phosphoric acid at the white heat.

Hydrogene, charcoal, sulphur, iron, and the compound inflammable bodies, decompose it only at heats equal to, or above, that of ignition: _probably_ each a different temperature.

From the phænomena in Sect. V. it appears, that at the temperature of intense ignition, phosphorus has a stronger affinity for the oxygene of nitrous oxide than hydrogene; and reasoning from the different degrees of combustibility of the inflammable bodies, in mixtures of nitrous oxide and nitrogene, and from other phænomena, we may conclude with probability, that at about the white heat, the affinity of the combustible bodies for oxygene takes place in the following order. Phosphorus, hydrogene, charcoal,[179] iron, sulphur, &c.