Experiments and Observations on Different Kinds of Air Part 16

This, indeed, is hardly agreeable to the hypothesis of most chemists, who suppose that the nitrous acid is stronger than the marine, so as to be capable of dislodging it from any base with which it may be combined; but it agrees with my own experiments on marine acid air, which shew that, in many cases, this _weaker acid_, as it is called, is capable of separating both the vitriolic and the nitrous acids from the phlogiston with which they are combined.

On the other hand, the solution of metals in the different acids seems to shew, that the nitrous acid forms a closer union with phlogiston than the other two; because the air which is formed by the nitrous acid is not inflammable, like that which is produced by the oil of vitriol, or the spirit of salt. Also, the same weight of iron does not yield half the quant.i.ty of nitrous air that it does of inflammable.

The great diminution of nitrous air by phlogiston is not easily accounted for, unless we suppose that its superabundant acid, uniting more intimately with the phlogiston, const.i.tutes a species of _sulphur_ that is not easily perceived or catched; though, in the process with iron, and also in that with liver of sulphur, part of the redundant phlogiston forms such an union with the acid as gives it a kind of inflammability.

It appears to me to be very probable, that the spirit of nitre might be exhibited in the form of _air_, if it were possible to find any fluid by which it could be confined; but it unites with quicksilver as well as with water, so that when, by boiling the spirit of nitre, the fumes are driven through the gla.s.s tube, fig. 8, they instantly seize upon the quicksilver through which they are to be conveyed, and uniting with it, form a substance that stops up the tube: a circ.u.mstance which has more than once exposed me to very disagreeable accidents, in consequence of the bursting of the phials.

I do not know any inquiry more promising than the investigation of the properties of _nitre_, the _nitrous acid_, and _nitrous air_. Some of the most wonderful phenomena in nature are connected with them, and the subject seems to be fully within our reach.

-- 2. _Speculations arising from the consideration of the similarity of the ELECTRIC MATTER and PHLOGISTON._

There is nothing in the history of philosophy more striking than the rapid progress of _electricity_. Nothing ever appeared more trifling than the first effects which were observed of this agent in nature, as the attraction and repulsion of straws, and other light substances. It excited more attention by the flashes of _light_ which it exhibited. We were more seriously alarmed at the electrical _shock_, and the effects of the electrical _battery_; and we were astonished to the highest degree by the discovery of the similarity of electricity with _lightning_, and the _aurora borealis_, with the connexion it seems to have with _water-spouts_, _hurricanes_, and _earthquakes_, and also with the part that is probably a.s.signed to it in the system of _vegetation_, and other the most important processes in nature.

Yet, notwithstanding all this, we have been, within a few years, more puzzled than ever with the electricity of the _torpedo_, and of the _anguille temblante_ of Surinam, especially since that most curious discovery of Mr. Walsh's, that the former of these wonderful fishes has the power of giving a proper electrical shock; the electrical matter which proceeds from it performing a real circuit from one part of the animal to the other; while both the fish which performs this experiment and all its apparatus are plunged in water, which is known to be a conducting substance.

Perhaps, however, by considering this fact in connexion with a few others, and especially with what I have lately observed concerning the ident.i.ty of electricity and phlogiston, a little light may be thrown upon this subject, in consequence of which we may be led to consider electricity in a still more important light. Many of my readers, I am aware, will smile at what I am going to advance; but the apprehension of this shall not interrupt my speculations, how chimerical soever they may be thought to be.

The facts, the consideration of which I would combine with that of the electricity of the torpedo, are the following.

First, The remarkable electricity of the feathers of a paroquet, observed by Mr. Hartmann, an account of which may be seen in Mr.

Rozier's Journal for Sept. 1771. p. 69. This bird never drinks, but often washes itself; but the person who attended it having neglected to supply it with water for this purpose, its feathers appeared to be endued with a proper electrical virtue, repelling one another, and retaining their electricity a long time after they were plucked from the body of the bird, just as they would have done if they had received electricity from an excited gla.s.s tube.

Secondly, The electric matter directed through the body of any muscle forces it to contract. This is known to all persons who attend to what is called the electrical shock; which certainly occasions a proper _convulsion_, but has been more fully ill.u.s.trated by Father Beccaria.

See my _History of Electricity_, p. 402.

Lastly, Let it be considered that the proper nourishment of an animal body, from which the source and materials of all muscular motion must be derived, is probably some modification of phlogiston. Nothing will nourish that does not contain phlogiston, and probably in such a state as to be easily separated from it by the animal functions.

That the source of muscular motion is phlogiston is still more probable, from the consideration of the well known effects of vinous and spirituous liquors, which consist very much of phlogiston, and which instantly brace and strengthen the whole nervous and muscular system; the phlogiston in this case being, perhaps, more easily extricated, and by a less tedious animal process, than in the usual method of extracting it from mild aliments. Since, however, the mildest aliments do the same thing more slowly and permanently, that spirituous liquors do suddenly and transiently, it seems probable that their operation is ultimately the same.

This conjecture is likewise favoured by my observation, that respiration and putrefaction affect common air in the same manner, and in the same manner in which all other processes diminish air and make it noxious, and which agree in nothing but the emission of phlogiston. If this be the case, it should seem that the phlogiston which we take in with our aliment, after having discharged its proper function in the animal system (by which it probably undergoes some unknown alteration) is discharged as _effete_ by the lungs into the great common _menstruum_, the atmosphere.

My conjecture suggested (whether supported or not) by these facts, is, that animals have a power of converting phlogiston, from the state in which they receive it in their nutriment, into that state in which it is called the electrical fluid; that the brain, besides its other proper uses, is the great laboratory and repository for this purpose; that by means of the nerves this great principle, thus exalted, is directed into the muscles, and forces them to act, in the same manner as they are forced into action when the electric fluid is thrown into them _ab extra_.

I farther suppose, that the generality of animals have no power of throwing this generated electricity any farther than the limits of their own system; but that the _torpedo_, and animals of a similar construction, have likewise the power, by means of an additional apparatus, of throwing it farther, so as to affect other animals, and other substances at a distance from them.

In this case, it should seem that the electric matter discharged from the animal system (by which it is probably more exhausted and fatigued than by ordinary muscular motion) would never return to it, at least so as to be capable of being made use of a second time, and yet if the structure of these animals be such as that the electric matter shall dart from one part of them only, while another part is left suddenly deprived of it, it may make a circuit, as in the Leyden phial.

As to the _manner_ in which the electric matter makes a muscle contract, I do not pretend to have any conjecture worth mentioning. I only imagine that whatever can make the muscular fibres recede from one another farther than the parts of which they consist, must have this effect.

Possibly, the _light_ which is said to proceed from some animals, as from cats and wild beasts, when they are in pursuit of their prey in the night, may not only arise, as it has. .h.i.therto been supposed to do, from the friction of their hairs or bristles, &c. but that violent muscular exertion may contribute to it. This may a.s.sist them occasionally to catch their prey; as glow-worms, and other insects, are provided with a constant light for that purpose, to the supply of which light their nutriment may also contribute.

I would not even say that the light which is said to have proceeded from some human bodies, of a particular temperament, and especially on some extraordinary occasions, may not have been of the electrical kind, that is, produced independently of friction, or with less friction than would have produced it in other persons; as in those cases related by Bartholin in his treatice _De luce animalium_. See particularly what he says concerning Theodore king of the Goths, p. 54, concerning Gonzaga duke of Mantua, p. 57, and Gothofred Antonius, p. 123: But I would not have my readers suppose that I lay much stress upon stories no better authenticated than these.

The electric matter in pa.s.sing through non-conducting substances always emits _light_. This light I have been sometimes inclined to suspect might have been supplied from the substance through which it pa.s.ses. But I find that after the electric spark has diminished a quant.i.ty of air as much as it possibly can, so that it has no more visible effect upon it, the electric light in that air is not at all lessened. It is probable, therefore, that electric light comes from the electric matter itself; and this being a modification of phlogiston, it is probable that _all light_ is a modification of phlogiston also. Indeed, since no other substances besides such as contain phlogiston are capable of ignition, and consequently of becoming luminous, it was on this account pretty evident, prior to these deductions from electrical phenomena, that light and phlogiston are the same thing, in different forms or states.

It appears to me that _heat_ has no more proper connexion with phlogiston than it has with water, or any other const.i.tuent part of bodies; but that it is a state into which the parts of bodies are thrown by their action and reaction with respect to one another; and probably (as the English philosophers in general have supposed) the heated state of bodies may consist of a subtle vibratory motion of their parts. Since the particles which const.i.tute light are thrown from luminous bodies with such amazing velocity, it is evident that, whatever be the cause of such a projection, the reaction consequent upon it must be considerable.

This may be sufficient not only to keep up, but also to increase the vibration of the parts of those bodies in which the phlogiston is not very firmly combined; and the difference between the substances which are called _inflammable_ and others which also contain phlogiston may be this, that in the former the heat, or the vibration occasioned by the emission of their own phlogiston, may be sufficient to occasion the emission of more, till the whole be exhausted; that is, till the body be reduced to ashes. Whereas in bodies which are not inflammable, the heat occasioned by the emission of their own phlogiston may not be sufficient for this purpose, but an additional heat _ab extra_ may be necessary.

Some philosophers dislike the term _phlogiston_; but, for my part, I can see no objection to giving that, or any other name, to a _real something_, the presence or absence of which makes so remarkable difference in bodies, as that of _metallic calces_ and _metals_, _oil of vitriol_ and _brimstone_, &c. and which may be transferred from one substance to another, according to certain known laws, that is, in certain definite circ.u.mstances. It is certainly hard to conceive how any thing that answers this description can be only a mere _quality_, or mode of bodies, and not _substance_ itself, though incapable of being exhibited alone. At least, there can be no harm in giving this name to any _thing_, or any _circ.u.mstance_ that is capable of producing these effects. If it should hereafter appear not to be a substance, we may change our phraseology, if we think proper.

On the other hand I dislike the use of the term _fire_, as a const.i.tuent principle of natural bodies, because, in consequence of the use that has generally been made of that term, it includes another thing or circ.u.mstance, viz. _heat_, and thereby becomes ambiguous, and is in danger of misleading us. When I use the term phlogiston, as a principle in the const.i.tution of bodies, I cannot mislead myself or others, because I use one and the same term to denote only one and the same _unknown cause_ of certain well-known effects. But if I say that _fire_ is a principle in the const.i.tution of bodies, I must, at least, embarra.s.s myself with the distinction of fire _in a state of action_, and fire _inactive_, or quiescent. Besides I think the term phlogiston preferable to that of fire, because it is not in common use, but confined to philosophy; so that the use of it may be more accurately ascertained.

Besides, if phlogiston and the electric matter be the same thing, though it cannot be exhibited alone, in a _quiescent state_, it may be exhibited alone under one of its modifications, when it is in _motion_.

And if light be also phlogiston, or some modification or subdivision of phlogiston, the same thing is capable of being exhibited alone in this other form also.

In my paper on the _conducting power of charcoal_, (See Philosophical Transactions, vol. 60. p. 221) I observed that there is a remarkable resemblance between metals and charcoal; as in both these substances there is an intimate union of phlogiston with an earthy base; and I said that, had there been any phlogiston in _water_, I should have concluded, that there had been no conducting power in nature, but in consequence of an union of this principle with some base; for while metals have phlogiston they conduct electricity, but when they are deprived of it they conduct no longer. Now the affinity which I have observed between phlogiston and water leads me to conclude that water, in its natural state, does contain some portion of phlogiston; and according to the hypothesis just now mentioned they must be intimately united, because water is not inflammable.

I think, therefore, that after this state of hesitation and suspence, I may venture to lay it down as a characteristic distinction between conducting and non-conducting substances, that the former contain phlogiston intimately united with some base, and that the latter, if they contain phlogiston at all, retain it more loosely. In what manner this circ.u.mstance facilitates the pa.s.sing of the electric matter through one substance, and obstructs its pa.s.sage through another, I do not pretend to say. But it is no inconsiderable thing to have advanced but _one step_ nearer to an explanation of so very capital a distinction of natural bodies, as that into conductors and non-conductors of electricity.

I beg leave to mention in this place, as favourable to this hypothesis, a most curious discovery made very lately by Mr. Walsh, who being a.s.sisted by Mr. De Luc to make a more perfect vacuum in the double or arched barometer, by boiling the quicksilver in the tube, found that the electric spark or shock would no more pa.s.s through it, than through a stick of solid gla.s.s. He has also noted several circ.u.mstances that affect this vacuum in a very extraordinary manner. But supposing that vacuum to be perfect, I do not see how we can avoid inferring from the fact, that some _substance_ is necessary to conduct electricity; and that it is not capable, by its own expansive power, of extending itself into s.p.a.ces void of all matter, as has generally been supposed, on the idea of there being nothing to obstruct its pa.s.sage.

Indeed if this was the case, I do not see how the electric matter could be retained within the body of the earth, or any of the planets, or solid orbs of any kind. In nature we see it make the most splendid appearance in the upper and thinner regions of the atmosphere, just as it does in a gla.s.s tube nearly exhausted; but if it could expand itself beyond that degree of rarity, it would necessarily be diffused into the surrounding vacuum, and continue and be condensed there, at least in a greater proportion than in or near any solid body, as Newton supposed concerning his _ether_.

If that mode of vibration which const.i.tutes heat be the means of converting phlogiston from that state in which it makes a part of solid bodies, and eminently contributes to the firmness of their texture into that state in which it diminishes common air; may not that peculiar kind of vibration by which Dr. Hartley supposes the brain to be affected, and by which he endeavours to explain all the phenomena of sensation, ideas, and muscular motion, be the means by which the phlogiston, which is conveyed into the system by nutriment, is converted into that form or modification of it of which the electric fluid consists.

These two states of phlogiston may be conceived to resemble, in some measure, the two states of fixed air, viz. elastic, or non-elastic; a solid, or a fluid.

THE APPENDIX.

In this Appendix I shall present the reader with the communications of several of my friends on the subject of the preceding work. Among them I should with pleasure have inserted some curious experiments, made by Dr.

Hulme of Halifax, on the air extracted from Buxton water, and on the impregnation of several fluids, with different kinds of air; but that he informs me he proposes to make a separate publication on the subject.

NUMBER I.

_EXPERIMENTS made by Mr. Hey to prove that there is no OIL of VITRIOL in water impregnated with FIXED AIR._

It having been suggested, that air arising from a fermenting mixture of chalk and oil of vitriol might carry up with it a small portion of the vitriolic acid, rendered volatile by the act of fermentation; I made the following experiments, in order to discover whether the acidulous taste, which water impregnated with such air affords, was owing to the presence of any acid, or only to the fixed air it had absorbed.

EXPERIMENT I.

I mixed a tea-spoonful of syrup of violets with an ounce of distilled water, saturated with fixed air procured from chalk by means of the vitriolic acid; but neither upon the first mixture, nor after standing 24 hours, was the colour of the syrup at all changed, except by its simple dilution.

EXPERIMENT II.

A portion of the same distilled water, unimpregnated with fixed air, was mixed with the syrup in the same proportion: not the least difference in colour could be perceived betwixt this and the above-mentioned mixture.

EXPERIMENT III.

One drop of oil of vitriol being mixed with a pint of the same distilled water, an ounce of this water was mixed with a tea-spoonful of the syrup. This mixture was very distinguishable in colour from the two former, having a purplish cast, which the others wanted.

EXPERIMENT IV.