The most important of them is a confirmation of my conjecture, that

fixed air is capable of forming an union with phlogiston, and thereby

becoming a kind of air that is not miscible with water. I had produced

this effect before by means of iron filings and brimstone, fermenting in

this kind of air; but I have since had a much more decisive and elegant

proof of it by _electricity_. For after taking a small electric

explosion, for about an hour, in the space of an inch of fixed air,

confined in a glass tube one tenth of an inch in diameter, fig. 16, I

found that when water was admitted to it, only one fourth of the air was

imbibed. Probably the whole of it would have been rendered immiscible in

water, if the electrical operation had been continued a sufficient time.

This air continued several days in water, and was even agitated in water

without any farther diminution. It was not, however, common air, for it

was not diminished by nitrous air.

By means of iron filings and brimstone I have, since my former

experiments, procured a considerable quantity of this kind of air in a

method something different from that which I used before. For having

placed a pot of this mixture under a receiver, and exhausted it with a

pump of Mr. Smeaton's construction, I filled it with fixed air, and then

left it plunged under water; so that no common air could have access to

it. In this manner, and in about a week, there was, as near as I can

recollect, one sixth, or at least one eighth of the whole converted into

a permanent air, not imbibed by water.

From this experiment I expected that the same effect would have been

produced on fixed air by the fumes of _liver of sulphur_; but I was

disappointed in that expectation, which surprised me not a little;

though this corresponds in some measure, to the effect of phlogiston

exhaled from this substance on acid air. Perhaps more time may be

requisite for this purpose, for this process was not continued more than

a day and a night.

Iron filings and brimstone, I have observed, ferment with great heat in

nitrous air, and I have since observed that this process is attended

with greater heat in fixed air than in common air.

Though fixed air incorporated with water dissolves iron, fixed air

without water has no such power, as I observed before. I imagined that,

if it could have dissolved iron, the phlogiston would have united with

the air, and have made it immiscible with water, as in the former

instances; but after being confined in a phial full of nails from the

15th of December to the 4th of October following, neither the iron nor

the air appeared to have been affected by their mutual contact.

Having exposed equal quantities of common and fixed air, in equal and

similar cylindrical glass vessels, to equal degrees of heat, by placing

them before a fire, and frequently changing their situations, I observed

that they were expanded exactly alike, and when removed from the fire

they both recovered their former dimensions.

Having had some small suspicion that liver of sulphur, besides emitting

phlogiston, might also yield some fixed air (which is known to be

contained in the salt of tartar from which it is made) I mixed the two

ingredients, viz. salt of tartar and brimstone, and putting them into a

thin phial, and applying the flame of a candle to it, so as to form the

liver of sulphur, I received the air that came from it in this process

in a vessel of quicksilver. In this manner I procured a very

considerable quantity of fixed air, so that I judged it was all

discharged from the tartar. But though it is possible that a small

quantity of it may remain in liver of sulphur, when it is made in the

most perfect manner, it is not probable that it can be expelled without

heat.

SECTION VII.

MISCELLANEOUS EXPERIMENTS.

1. It is something extraordinary that, though ether, as I found, cannot

be made to assume the form of air (the vapour arising from it by heat,

being soon condensed by cold, even in quicksilver) yet that a very small

quantity of ether put to any kind of air, except the acid, and alkaline,

which it imbibes, almost instantly doubles the apparent quantity of it;

but upon passing this air through water, it is presently reduced to its

original quantity again, with little or no change of quality.

I put about the quantity of half a nut-shell full of ether, inclosed in

a glass tube, through a body of quicksilver, into an ounce measure of

common air, confined by quicksilver; upon which it presently began to

expand, till it occupied the space of two ounce measures. It then

gradually contracted about one sixth of an ounce measure. Putting more

ether to it, it again expanded to two ounce measures; but no more

addition of ether would make it expand any farther. Withdrawing the

quicksilver, and admitting water to this air, without any agitation, it

began to be absorbed; but only about half an ounce measure had

disappeared after it had stood an hour in the water. But by once passing

it through water the air was reduced to its original dimensions. Being

tried by a mixture of nitrous air, it appeared not to be so good as

fresh air, though the injury it had received was not considerable.

All the phenomena of dilatation and contraction were nearly the same,

when, instead of common air, I used nitrous air, fixed air, inflammable

air, or any species of phlogisticated common air. The quantity of each

of these kinds of air was nearly doubled while they were kept in

quicksilver, but fixed air was not so much increased as the rest, and

phlogisticated air less; but after passing through the water, they

appeared not to have been sensibly changed by the process.

2. Spirit of wine yields no air by means of heat, the vapours being soon

condensed by cold, like the vapour of water; yet when, in endeavouring

to procure air from it, I made it boil, and catched the air which had

rested on the surface of the spirit, and which had been expelled by the

heat together with the vapour, in a vessel of quicksilver, and

afterwards admitted acid air to it, the vessel was filled with white

fumes, as if there had been a mixture of alkaline air along with it. To

what this appearance was owing I cannot tell, and indeed I did not

examine into it.

3. Having been informed by Dr. Small and Mr. Bolton of Birmingham, that

paper dipped in a solution of copper in spirit of nitre would take fire

with a moderate heat (a fact which I afterwards found mentioned in the

Philosophical Transactions) it occurred to me that this would be very

convenient for experiments relating to _ignition_ in different kinds of

air; and indeed I found that it was easily fired, either by a burning

lens, or the approach of red-hot iron on the outside of the phial in

which it was contained, and that any part of it being once fired, the

whole was presently reduced to ashes; provided it was previously made

thoroughly dry, which, however, it is not very easy to do.

With this preparation, I found that this paper burned freely in all

kinds of air, but not in _vacuo_, which is also the case with gunpowder;

and, as I have in effect observed before, all the kinds of air in which

this paper was burned received an addition to their bulk, which

consisted partly of nitrous air, from the nitrous precipitate, and

partly of inflammable air, from the paper. As some of the circumstances

attending the ignition of this paper in some of the kinds of air were a

little remarkable, I shall just recite them.

Firing this paper in _inflammable_ air, which it did without any

ignition of the inflammable air itself, the quantity increased

regularly, till the phial in which the process was made was nearly full;

but then it began to decrease, till one third of the whole quantity

disappeared.

A piece of this paper being put to three ounce measures of _acid_ air, a

great part of it presently turned yellow, and the air was reduced to one

third of the original quantity, at the same time becoming reddish,

exactly like common air in a phial containing smoking spirit of nitre.

After this, by the approach of hot iron, I set fire to the paper;

immediately upon which there was a production of air which more than

filled the phial. This air appeared, upon examination, to be very little

different from pure nitrous air. I repeated this experiment with the

same event.

Paper dipped in a solution of mercury, zinc, or iron, in nitrous acid,

has, in a small degree, the same property with paper dipped in a

solution of copper in the same acid.

4. Gunpowder is also fired in all kinds of air, and, in the quantity in

which I tried it, did not make any sensible change in them, except that

the common air in which it was fired would not afterwards admit a candle

to burn in it. In order to try this experiment I half exhausted a

receiver, and then with a burning-glass fired the gunpowder which had

been previously put into it. By this means I could fire a greater

quantity of gunpowder in a small quantity of air, and avoid the hazard

of blowing up, and breaking my receiver.

I own that I was rather afraid of firing gunpowder in inflammable air,

but there was no reason for my fear; for it exploded quite freely in

this air, leaving it, in all respects, just as it was before.

In order to make this experiment, and indeed almost all the experiments

of firing gunpowder in different kinds of air, I placed the powder upon

a convenient stand within my receiver, and having carefully exhausted it

by a pump of Mr. Smeaton's construction, I filled the receiver with any

kind of air by the apparatus described, p. 19, fig. 14, taking the

greatest care that the tubes, &c. which conveyed the air should contain

little or no common air. In the experiment with inflammable air a

considerable mixture of common air would have been exceedingly

hazardous: for, by that assistance, the inflammable air might have

exploded in such a manner, as to have been dangerous to the operator.

Indeed, I believe I should not have ventured to have made the experiment

at all with any other pump besides Mr. Smeaton's.

Sometimes, I filled a glass vessel with quicksilver, and introduced the

air to it, when it was inverted in a bason of quicksilver. By this means

I intirely avoided any mixture of common air; but then it was not easy

to convey the gunpowder into it, in the exact quantity that was

requisite for my purpose. This, however, was the only method by which I

could contrive to fire gunpowder in acid or alkaline air, in which it

exploded just as it did in nitrous or fixed air.

I burned a considerable quantity of gunpowder in an exhausted receiver

(for it is well known that it will not explode in it) but the air I got

from it was very inconsiderable, and in these circumstances was

necessarily mixed with common air. A candle would not burn in it.

SECTION VIII.

_QUERIES, SPECULATIONS, and HINTS._

I begin to be apprehensive lest, after being considered as a _dry

experimenter_, I should pass, with many of my readers, into the opposite

character of a _visionary theorist_. A good deal of theory has been

interspersed in the course of this work, but, not content with this, I

am now entering upon a long section, which contains nothing else.

The conjectures that I have ventured to advance in the body of the work

will, I hope, be found to be pretty well supported by facts; but the

present section will, I acknowledge, contain many _random thoughts_. I

have, however, thrown them together by themselves, that readers of less

imagination, and who care not to advance beyond the regions of plain

fact, may, if they please, proceed no farther, that their delicacy be

not offended.

In extenuation of my offence, let it, however, be considered, that

_theory_ and _experiment_ necessarily go hand in hand, every process

being intended to ascertain some particular _hypothesis_, which, in

fact, is only a conjecture concerning the circumstances or the cause of

some natural operation; consequently that the boldest and most original

experimenters are those, who, giving free scope to their imaginations,

admit the combination of the most distant ideas; and that though many of

these associations of ideas, will be wild and chimerical, yet that

others will have the chance of giving rise to the greatest and most

capital discoveries; such as very cautious, timid, sober, and

slow-thinking people would never have come at.

Sir Isaac Newton himself, notwithstanding the great advantage which he

derived from a habit of _patient thinking_, indulged bold and excentric

thoughts, of which his Queries at the end of his book of Optics are a

sufficient evidence. And a quick conception of distant analogies, which

is the great key to unlock the secret of nature, is by no means

incompatible with the spirit of _perseverance_, in investigations

calculated to ascertain and pursue those analogies.

Sec. 1. _Speculations concerning the CONSTITUENT PRINCIPLES of the

different kinds of AIR, and the CONSTITUTION and ORIGIN of the

ATMOSPHERE, &c._

All the kinds of air that appear to me to be essentially distinct from

each other are _fixed air_, _acid_ and _alkaline_; for these, and

another principle, called _phlogiston_, which I have not been able to

exhibit in the form of _air_, and which has never yet been exhibited by

itself in _any form_, seem to constitute all the kinds of air that I am

acquainted with.

Acid air and phlogiston constitute an air which either extinguishes

flame, or is itself inflammable, according, probably, to the quantity of

phlogiston combined in it, or the mode of combination. When it

extinguishes flame, it is probably so much charged with the phlogistic

matter, as to take no more from a burning candle, which must, therefore,

necessarily go out in it. When it is inflammable, it is probably so much

charged with phlogiston, that the heat communicated by a burning candle

makes it immediately separate itself from the other principle with which

it was united, in which separation _heat_ is produced, as in other cases

of ignition; the action and reaction, which necessarily attends the

separation of the constituent principles, exciting probably a vibratory

motion in them.

Since inflammable, air, by agitation in water, first comes to lose its

inflammability, so as to be fit for respiration, and even to admit a

candle to burn in it, and then comes to extinguish a candle; it seems

probable that water imbibes a great part of this extraordinary charge of

phlogiston. And that water _can_ be impregnated with phlogiston, is

evident from many of my experiments, especially those in which metals

were calcined over it.

Water having this affinity with phlogiston, it is probable that it

always contains a considerable portion of it; which phlogiston having a

stronger affinity with the acid air, which is perhaps the basis of

common air, may by long agitation be communicated to it, so as to leave

it over saturated, in consequence of which it will extinguish a candle.

It is possible, however, that inflammable air and air which extinguishes

a candle may differ from one another in the _mode_ of the combination of

these two constituent principles, as well as in the proportional

quantity of each; and by agitation in water, or long standing, that mode

of combination may change. This we know to be the case with other

substances, as with _milk_, from which, by standing only, _cream_ is

separated; which by agitation becomes _butter_. Also many substances,

being at rest, putrefy, and thereby become quite different from what

they were before. If this be the case with inflammable air, the water

may imbibe either of the constituent parts, whenever any proportion of

it is spontaneously separated from the rest; and should this ever be

that phlogiston, with which air is but slightly overcharged, as by the

burning of a candle, it will be recovered to a state in which a candle

may burn in it again.

It will be observed, however, that it was only in one instance that I

found that strong inflammable air, in its transition to a state in which

it extinguishes a candle, would admit a candle to burn in it, and that

was very faintly; that then the air was far from being pure, as appeared

by the test of nitrous air; and that it was only from a particular

quantity of inflammable air which I got from oak, and which had stood a

long time in water, that I ever got air which was as pure as common air.

Indeed, it is much more easy to account for the passing of inflammable

air into a state in which it extinguishes candles, without any

intermediate state, in which it will admit a candle to burn in it, than

otherwise. This subject requires and deserves farther investigation. It

will also be well worth while to examine what difference the agitation

of air in natural or artificial _sea-water_ will occasion.

Since acid air and phlogiston make inflammable air, and since

inflammable air is convertible into air fit for respiration, it seems

not to be improbable, that these two ingredients are the only essential

principles of common air. For this change is produced by agitation in

water only, without the addition of any fixed air, though this kind of

air, like various other things of a foreign nature, may be combined with

it.

Considering also what prodigious quantities of inflammable air are

produced by the burning of small pieces of wood or pit-coal, it may not

be improbable but that the _volcanos_, with which there are evident

traces of almost the whole surface of the earth having been overspread,

may have been the origin of our atmosphere, as well as (according to the

opinion of some) of all the solid land.

The superfluous phlogiston of the air, in the state in which it issues

from volcanos, may have been imbibed by the waters of the sea, which it

is probable originally covered the surface of the earth, though part of

it might have united with the acid vapour exhaled from the sea, and by

this union have made a considerable and valuable addition to the common

mass of air; and the remainder of this over-charge of phlogiston may

have been imbibed by plants as soon as the earth was furnished with

them.

That an acid vapour is really exhaled from the sea, by the heat of the

sun, seems to be evident from the remarkably different states of the

atmosphere, in this respect, in hot and cold climates. In Hudson's bay,

and also in Russia, it is said, that metals hardly ever rust, whereas

they are remarkably liable to rust in Barbadoes, and other islands

between the tropics. See Ellis's Voyage, p. 288. This is also the case

in places abounding with salt-springs, as Nantwich in Cheshire.

That mild air should consist of parts of so very different a nature as

an acid vapour and phlogiston, one of which is so exceedingly corrosive,

will not appear surprising to a chemist, who considers the very strong

affinity which these two principles are known to have with each other,

and the exceedingly different properties which substances composed by

them possess. This is exemplified in common _sulphur_, which is as mild

as air, and may be taken into the stomach with the utmost safety, though

nothing can be more destructive than one of its constituent parts,

separately taken, viz. oil of vitriol. Common air, therefore,

notwithstanding its mildness, may be composed of similar principles, and

be a real _sulphur_.

That the fixed air which makes part of the atmosphere is not presently

imbibed by the waters of the sea, on which it rests, may be owing to the

union which this kind of air also appears to be capable of forming with

phlogiston. For fixed air is evidently of the nature of an acid; and it

appears, in fact, to be capable of being combined with phlogiston, and

thereby of constituting a species of air not liable to be imbibed by

water. Phlogiston, however, having a stronger affinity with acid air,

which I suppose to be the basis of common air, it is not surprising

that, uniting with this, in preference to the fixed air, the latter

should be precipitated, whenever a quantity of common air is made

noxious by an over-charge of phlogiston.

The fixed air with which our atmosphere abounds may also be supplied by

volcanos, from the vast masses of calcareous matter lodged in the earth,

together with inflammable air. Also a part of it may be supplied from

the fermentation of vegetables upon the surface of it. At present, as

fast as it is precipitated and imbibed by one process, it may be set

loose by others.

Whether there be, upon, the whole, an increase or a decrease of the

general mass of the atmosphere is not easy to conjecture, but I should

imagine that it rather increases. It is true that many processes

contribute to a great visible diminution of common air, and that when by

other processes it is restored to its former wholesomeness, it is not

increased in its dimensions; but volcanos and fires still supply vast

quantities of air, though in a state not yet fit for respiration; and it

will have been seen in my experiments, that vegetable and animal

substances, dissolved by putrefaction, not only emit phlogiston, but

likewise yield a considerable quantity of permanent elastic air,

overloaded indeed with phlogiston, as might be expected, but capable of

being purified by those processes in nature by which other noxious air

is purified.

That particles are continually detaching themselves from the surfaces of

all solid bodies, even the metallic ones, and that these particles

constitute the most permanent part of the atmosphere, as Sir Isaac

Newton supposed, does not appear to me to be at all probable.

My readers will have observed, that not only is common air liable to be

diminished by a mixture of nitrous air, but likewise air originally

produced from inflammable air, and even from nitrous air itself, which

never contained any fixed air. From this it may be inferred, that the

whole of the diminution of common air by phlogiston is not owing to the

precipitation of fixed air, but from a real contraction of its

dimensions, in consequence of its union with phlogiston. Perhaps an

accurate attention to the specific gravity of air procured from these

different materials, and in these different states, may determine this

matter, and assist us in investigating the nature of phlogiston.

In what _manner_ air is diminished by phlogiston, independent of the

precipitation of any of its constituent parts, is not easy to conceive;

unless air thus diminished be heavier than air not diminished, which I

did not find to be the case. It deserves, however, to be tried with more

attention. That phlogiston should communicate absolute _levity_ to the

bodies with which it is combined, is a supposition that I am not willing

to have recourse to, though it would afford an easy solution of this

difficulty.

I have likewise observed, that a mouse will live almost as long in

inflammable air, when it has been agitated in water, and even before it

has been deprived of all its inflammability, as in common air; and yet

that in this state it is not, perhaps, so much diminished by nitrous air

as common air is. In this case, therefore, the diminution seems to have

been occasioned by a contraction of dimensions, and not by a loss of any

constituent part; so that the air is really better, that is, more fit

for respiration, than, by the test of nitrous air, it would seem to be.

If this be the case (for it is not easy to judge with accuracy by

experiments with small animals) nitrous air will be an accurate test of

the goodness of _common air_ only, that is, air containing a

considerable proportion of fixed air. But this is the most valuable

purpose for which a test of the goodness of air can be wanted. It will

still, indeed, serve for a measure of the goodness of air that does not

contain fixed air; but, a smaller degree of diminution in this case,

must be admitted to be equivalent to a greater diminution in the other.

As I could never, by means of growing vegetables, bring air which had

been thoroughly noxious to so pure a state as that a candle would burn

in it, it may be suspected that something else besides _vegetation_ is

necessary to produce this effect. But it should be considered, that no

part of the common atmosphere can ever be in this highly noxious state,

or indeed in a state in which a candle will not burn in it; but that

even air reduced to this state, either by candles actually burning out

in it, or by breathing it, has never failed to be perfectly restored by

vegetation, at least so far that candles would burn in it again, and, to

all appearance, as well, and as long as ever; so that the growing

vegetables, with which the surface of the earth is overspread, may, for

any thing that appears to the contrary, be a cause of the purification

of the atmosphere sufficiently adequate to the effect.

It may likewise be suspected, that since _agitation in water_ injures

pure common air, the agitation of the sea may do more harm than good in

this respect. But it requires a much more violent and longer continued

agitation of air in water than is ever occasioned by the waves of the

sea to do the least sensible injury to it. Indeed a light agitation of

air in _putrid water_ injures it very materially; but if the water be

sweet, this effect is not produced, except by a long and tedious

operation, whereas it requires but a very short time, in comparison, to

restore a quantity of any of the most noxious kinds of air to a very

great degree of wholesomeness by the same process.

Dr. Hales found that he could breathe the same air much longer when, in

the course of his respiration, it was made to pass through several folds

of cloth dipped in vinegar, in a solution of sea-salt, or in salt of

tartar, especially the last. Statical Essays, vol. 1. p. 266. The

experiment is valuable, and well deserves to be repeated with a greater

variety of circumstances. I imagine that the effect was produced by

those substances, or by the _water_ which they attracted from the air,

imbibing the phlogistic matter discharged from the lungs. Perhaps the

phlogiston may unite with the watery part of the atmosphere, in

preference to any other part of it, and may by that means be more easily

transferred to such salts as imbibe moisture.

Sir Isaac Newton defines _flame_ to be _fumus candens_, considering all

_smoke_ as being of the same nature, and capable of ignition. But the

smoke of common fuel consists of two very different things. That which

rises first is mere _water_, loaded with some of the grosser parts of

the fuel, and is hardly more capable of becoming red hot than water

itself; but the other kind of smoke, which alone is capable of ignition,

is properly _inflammable air_, which is also loaded with other

heterogeneous matter, so as to appear like a very dense smoke. A lighted

candle soon shews them to be essentially different from each other. For

one of them instantly takes fire, whereas the other extinguishes a

candle.

It is remarkable that gunpowder will take fire, and explode in all kinds

of air, without distinction, and that other substances which contain

_nitre_ will burn freely in those circumstances. Now since nothing can

burn, unless there be something at hand to receive the phlogiston, which

is set loose in the act of ignition, I do not see how this fact can be

accounted for, but by supposing that the acid of nitre, being peculiarly

formed to unite with phlogiston, immediately receives it. And if the

sulphur, which is thereby formed, be instantly decomposed again, as the

chemists in general say, thence comes the explosion of gunpowder, which,

however, requires the reaction of some incumbent atmosphere, and without

which the materials will only _melt_, and be _dispersed_ without

explosion.

Nitrous air seems to consist of the nitrous acid vapour united to

phlogiston, together, perhaps, with some small portion of the metallic

calx; just as inflammable air consists of the vitriolic or marine acid,

and the same phlogistic principle. It should seem, however, that

phlogiston has a stronger affinity with the marine acid, if that be the

basis of common air; for nitrous air being admitted to common air, it is

immediately decomposed; probably by the phlogiston joining with the acid

principle of the common air, while the fixed air which it contained is

precipitated, and the acid of the nitrous air is absorbed by the water

in which the mixture is made, or unites with any volatile alkali that

happens to be at hand.

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 quantity 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, constitutes 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 glass 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 circumstance 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.

Sec. 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 assigned 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

identity 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 glass 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 illustrated 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 hitherto been supposed to do, from

the friction of their hairs or bristles, &c. but that violent muscular

exertion may contribute to it. This may assist 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 passing 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 passes. But

I find that after the electric spark has diminished a quantity 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 constituent 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 constitute 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 circumstances. 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 _circumstance_ 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 constituent

principle of natural bodies, because, in consequence of the use that has

generally been made of that term, it includes another thing or

circumstance, viz. _heat_, and thereby becomes ambiguous, and is in

danger of misleading us. When I use the term phlogiston, as a principle

in the constitution 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 constitution of bodies, I must, at least,

embarrass 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 circumstance facilitates the passing of the electric matter through

one substance, and obstructs its passage 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

assisted 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 pass through it, than through a

stick of solid glass. He has also noted several circumstances 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 spaces void of all matter, as has generally been supposed, on the

idea of there being nothing to obstruct its passage.

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 glass 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 constitutes 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.

The distilled water impregnated with so small a quantity of vitriolic

acid, having a more agreeable taste than when alone, and yet manifesting

the presence of an acid by means of the syrup of violets; I subjected it

to some other tests of acidity. It formed curds when agitated with soap,

lathered with difficulty, and very imperfectly; but not the least

ebullition could be discovered upon dropping in spirit of sal ammoniac,

or solution of salt of tartar, though I had taken care to render the

latter free from causticity by impregnating it with fixed air.

EXPERIMENT V.

The distilled water saturated with fixed air neither effervesced, nor

shewed any clouds, when mixed with the fixed or volatile alkali.

EXPERIMENT VI.

No curd was formed by pouring this water upon an equal quantity of milk,

and boiling them together.

EXPERIMENT VII.

When agitated with soap, this water produced curds, and lathered with

some difficulty; but not so much as the distilled water mixed with

vitriolic acid in the very small proportion above-mentioned. The same

distilled water without any impregnation of fixed air lathered with soap

without the least previous curdling. River-water, and a pleasant

pump-water not remarkably hard, were compared with these. The former

produced curds before it lathered, but not quite in so great a quantity

as the distilled water impregnated with fixed air: the latter caused a

stronger curd than any of the others above-mentioned.

EXPERIMENT VIII.

Apprehending that the fixed air in the distilled water occasioned the

coagulation, or separation of the oily part of the soap, only by

destroying the causticity of the _lixivium_, and thereby rendering the

union less perfect betwixt that and the tallow, and not by the presence

of any acid; I impregnated a fresh quantity of the same distilled water

with fixed air, which had passed through half a yard of a wide

barometer-tube filled with salt of tartar; but this water caused the

same curdling with soap as the former had done, and appeared in every

respect to be exactly the same.

EXPERIMENT IX.

Distilled water saturated with fixed air formed a white cloud and

precipitation, upon being mixed with a solution of _saccharum saturni_.

I found likewise, that fixed air, after passing through the tube filled

with alkaline salt, upon being let into a phial containing a solution of

the metalic salt in distilled water, caused a perfect separation of the

lead, in the form of a white powder; for the water, after this

precipitation, shewed no cloudiness upon a fresh mixture of the

substances which had before rendered it opaque.

NUMBER II.

_A Letter from Mr. HEY to Dr. PRIESTLEY, concerning the Effects

of fixed Air applied by way of Clyster._

Leeds, Feb. 15th, 1772.

Reverend Sir,

Having lately experienced the good effects of fixed air in a putrid

fever, applied in a manner, I believe not heretofore made use of, I

thought it proper to inform you of the agreeable event, as the method of

applying this powerful corrector of putrefaction took its rise

principally from your observations and experiments on factitious air;

and now, at your request, I send the particulars of the case I mentioned

to you, as far as concerns the administration of this remedy.

January 8, 1772, Mr. Lightbowne, a young gentleman who lives with me,

was seized with a fever, which, after continuing about ten days, began

to be attended with those symptoms that indicate a putrescent state of

the fluids.

18th, His tongue was black in the morning when I first visited him, but

the blackness went off in the day-time upon drinking: He had begun to

doze much the preceding day, and now he took little notice of those that

were about him: His belly was loose, and had been so for some days: his

pulse beat 110 strokes in a minute, and was rather low: he was ordered

to take twenty-five grains of Peruvian bark with five of tormentil-root

in powder every four hours, and to use red wine and water cold as his

common drink.

19th, I was called to visit him early in the morning, on account of a

bleeding at the nose which had come on: he lost about eight ounces of

blood, which was of a loose texture: the haemorrhage was suppressed,

though not without some difficulty, by means of tents made of soft lint,

dipped in cold water strongly impregnated with tincture of iron, which

were introduced within the nostrils quite through to their posterior

apertures; a method which has never yet failed me in like cases. His

tongue was now covered with a thick black pellicle, which was not

diminished by drinking: his teeth were furred with the same kind of

sordid matter, and even the roof of his mouth and sauces were not free

from it: his looseness and stupor continued, and he was almost

incessantly muttering to himself: he took this day a scruple of the

Peruvian bark with ten grains of tormentil every two or three hours: a

starch clyster, containing a drachm of the compound powder of bole,

without opium, was given morning and evening: a window was set open in

his room, though it was a severe frost, and the floor was frequently

sprinkled with vinegar.

20th, He continued nearly in the same state: when roused from his

dozing, he generally gave a sensible answer to the questions asked him;

but he immediately relapsed, and repeated his muttering. His skin was

dry, and harsh, but without _petechiae_. He sometimes voided his urine

and _faeces_ into the bed, but generally had sense enough to ask for the

bed-pan: as he now nauseated the bark in substance, it was exchanged

for Huxham's tincture, of which he took a table spoonful every two hours

in a cup full of cold water: he drank sometimes a little of the tincture

of roses, but his common liquors were red wine and water, or rice-water

and brandy acidulated with elixir of vitriol: before drinking, he was

commonly requested to rinse his mouth with water to which a little honey

and vinegar had been added. His looseness rather increased, and the

stools were watery, black, and foetid: It was judged necessary to

moderate this discharge, which seemed to sink him, by mixing a drachm of

the _theriaca Andromachi_ with each clyster.

21st. The same putrid symptoms remained, and a _subsultus tendinum_ came

on: his stools were more foetid; and so hot, that the nurse assured me

she could not apply her hand to the bed-pan, immediately after they were

discharged, without feeling pain on this account: The medicine and

clysters were repeated.

Reflecting upon the disagreeable necessity we seemed to lie under of

confining this putrid matter in the intestines, lest the evacuation

should destroy the _vis vitae_ before there was time to correct its bad

quality, and overcome its bad effects, by the means we were using; I

considered, that, if this putrid ferment could be more immediately

corrected, a stop would probably be put to the flux, which seemed to

arise from, or at least to be encreased by it; and the _fomes_ of the

disease would likewise be in a great measure removed. I thought nothing

was so likely to effect this, as the introduction of fixed air into the

alimentary canal, which, from the experiments of Dr. Macbride, and

those you have made since his publication, appears to be the most

powerful corrector of putrefaction hitherto known. I recollected what

you had recommended to me as deserving to be tried in putrid diseases, I

mean, the injection of this kind of air by way of clyster, and judged

that in the present case such a method was clearly indicated.

The next morning I mentioned my reflections to Dr. Hird and Dr.

Crowther, who kindly attended this young gentleman at my request, and

proposed the following method of treatment, which, with their

approbation, was immediately entered upon. We first gave him five grains

of ipecacuanha, to evacuate in the most easy manner part of the putrid

_colluvies_: he was then allowed to drink freely of brisk orange-wine,

which contained a good deal of fixed air, yet had not lost its

sweetness. The tincture of bark was continued as before; and the water

which he drank along with it, was impregnated with fixed air from the

atmosphere of a large vat of fermenting wort, in the manner I had

learned from you. Instead of the astringent clyster, air alone was

injected, collected from a fermenting mixture of chalk and oil of

vitriol: he drank a bottle of orange-wine in the course of this day, but

refused any other liquor except water and his medicine: two bladders

full of air were thrown up in the afternoon.

23d. His stools were less frequent; their heat likewise and peculiar

_foetor_ were considerably diminished; his muttering was much abated,

and the _subsultus tendinum_ had left him. Finding that part of the air

was rejected when given with a bladder in the usual way, I contrived a

method of injecting it which was not so liable to this inconvenience. I

took the flexible tube of that instrument which is used for throwing up

the fume of tobacco, and tied a small bladder to the end of it that is

connected with the box made for receiving the tobacco, which I had

previously taken off from the tube: I then put some bits of chalk into a

six ounce phial until it was half filled; upon these I poured such a

quantity of oil of vitriol as I thought capable of saturating the chalk,

and immediately tied the bladder, which I had fixed to the tube, round

the neck of the phial: the clyster-pipe, which was fastened to the other

end of the tube, was introduced into the _anus_ before the oil of

vitriol was poured upon the chalk. By this method the air passed

gradually into the intestines as it was generated; the rejection of it

was in a great measure prevented; and the inconvenience of keeping the

patient uncovered during the operation was avoided.

24th, He was so much better, that there seemed to be no necessity for

repeating the clysters: the other means were continued. The window of

his room was now kept shut.

25th, All the symptoms of putrescency had left him; his tongue and teeth

were clean; there remained no unnatural blackness or _foetor_ in his

stool, which had now regained their proper consistence; his dozing and

muttering were gone off; and the disagreeable odour of his breath and

perspiration was no longer perceived. He took nourishment to-day, with

pleasure; and, in the afternoon, sat up an hour in his chair.

His fever, however, did not immediately leave him; but this we

attributed to his having caught cold from being incautiously uncovered,

when the window was open, and the weather extremely severe; for a cough,

which had troubled him in some degree from the beginning, increased, and

he became likewise very hoarse for several days, his pulse, at the same

time, growing quicker: but these complaints also went off, and he

recovered, without any return of the bad symptoms above-mentioned.

I am, Reverend Sir,

Your obliged humble Servant,

WM. HEY.

POSTSCRIPT

October 29, 1772.

Fevers of the putrid kind have been so rare in this town, and in its

neighbourhood, since the commencement of the present year, that I have

not had an opportunity of trying again the effects of fixed air, given

by way of clyster, in any case exactly similar to Mr. Lightbowne's. I

have twice given water saturated with fixed air in a fever of the

putrescent kind, and it agreed very well with the patients. To one of

them the aerial clysters were administred, on account of a looseness,

which attended the fever, though the stools were not black, nor

remarkably hot or foetid.

These clysters did not remove the looseness, though there was often a

greater interval than usual betwixt the evacuations, after the injection

of them. The patient never complained of any uneasy distention of the

belly from the air thrown up, which, indeed, is not to be wondered at,

considering how readily this kind of air is absorbed by aqueous and

other fluids, for which sufficient time was given, by the gradual manner

of injecting it. Both those patients recovered though the use of fixed

air did not produce a crisis before the period at which such fevers

usually terminate. They had neither of them the opportunity of drinking

such wine as Mr. Lightbowne took, after the use of fixed air was entered

upon; and this, probably, was some disadvantage to them.

I find the methods of procuring fixed air, and impregnating water with

it, which you have published, are preferable to those I made use of in

Mr. Lightbowne's case.

The flexible tube used for conveying the fume of tobacco into the

intestines, I find to be a very convenient instrument in this case, by

the method before-mentioned (only adding water to the chalk, before the

oil of vitriol is instilled, as you direct) the injection of air may be

continued at pleasure, without any other inconvenience to the patient,

than what may arise from his continuing in one position during the

operation, which scarcely deserves to be mentioned, or from the

continuance of the clyster-pipe within the anus, which is but trifling,

if it be not shaken much, or pushed against the rectum.

When I said in my letter, that fixed air appeared to be the greatest

corrector of putrefaction hitherto known, your philosophical researches

had not then made you acquainted with that most remarkably antiseptic

property of nitrous air. Since you favoured me with a view of some

astonishing proofs of this, I have conceived hopes, that this kind of

air may likewise be applied medicinally to great advantage.

W. H.

NUMBER III.

_Observations on the MEDICINAL USES of FIXED AIR. By THOMAS

PERCIVAL, M. D. Fellow of the ROYAL SOCIETY, and of the SOCIETY

of ANTIQUARIES in LONDON._

These Observations on the MEDICINAL USES OF FIXED AIR have been before

published in the Second Volume of my Essays; but are here reprinted with

considerable additions. They form a part of an experimental inquiry into

this interesting and curious branch of Physics; in which the friendship

of Dr. Priestley first engaged me, in concert with himself.

Manchester, March 16, 1774.

In a course of Experiments, which is yet unfinished, I have had frequent

opportunities of observing that FIXED AIR may in no inconsiderable

quantity be breathed without danger or uneasiness. And it is a

confirmation of this conclusion, that at Bath, where the waters

copiously exhale this mineral spirit,[15] the bathers inspire it with

impunity. At Buxton also, where the Bath is in a close vault, the

effects of such _effluvia_, if noxious, must certainly be perceived.

Encouraged by these considerations, and still more by the testimony of a

very judicious Physician at Stafford, in favour of this powerful

antiseptic remedy, I have administered fixed air in a considerable

number of cases of the PHTHISIS PULMONALIS, by directing my patients to

inspire the steams of an effervescing mixture of chalk and vinegar; or

what I have lately preferred, of vinegar and potash. The hectic fever

has in several instances been considerably abated, and the matter

expectorated has become less offensive, and better digested. I have not

yet been so fortunate in any one case, as to effect a cure; although the

use of mephitic air has been accompanied with proper internal medicines.

But Dr. Withering, the gentleman referred to above, informs me, that he

has been more successful. One Phthisical patient under his care has by a

similar course intirely recovered; another was rendered much better; and

a third, whose case was truly deplorable, seemed to be kept alive by it

more than two months. It may be proper to observe that fixed air can

only be employed with any prospect of success, in the latter stages of

the _phthisis pulmonalis_, when a purulent expectoration takes place.

After the rupture and discharge of a VOMICA also, such a remedy promises

to be a powerful palliative. Antiseptic fumigations and vapours have

been long employed, and much extolled in cases of this kind. I made the

following experiment, to determine whether their efficacy, in any

degree, depends on the separation of fixed air from their substance.

One end of a bent tube was fixed in a phial full of lime-water; the

other end in a bottle of the tincture of myrrh. The junctures were

carefully luted, and the phial containing the tincture of myrrh was

placed in water, heated almost to the boiling point, by the lamp of a

tea-kettle. A number of air-bubbles were separated, but probably not of

the mephitic kind, for no precipitation ensued in the lime water. This

experiment was repeated with the _tinct. tolutanae, ph. ed._ and with

_sp, vinos. camp._ and the result was entirely the same. The medicinal

action therefore of the vapours raised from such tinctures, cannot be

ascribed to the extrication of fixed air; of which it is probable bodies

are deprived by _chemical solution_ as well as by _mixture_.

If mephitic air be thus capable of correcting purulent matter in the

lungs, we may reasonably infer it will be equally useful when applied

externally to foul ULCERS. And experience confirms the conclusion. Even

the sanies of a CANCER, when the carrot poultice failed, has been

sweetened by it, the pain mitigated, and a better digestion produced.

The cases I refer to are now in the Manchester infirmary, under the

direction of my friend Mr. White, whose skill as a surgeon, and

abilities as a writer are well known to the public.

Two months have elapsed since these observations were written,[16] and

the same remedy, during that period, has been assiduously applied, but

without any further success. The progress of the cancers seems to be

checked by the fixed air; but it is to be feared that a cure will not be

effected. A palliative remedy, however, in a disease so desperate and

loathsome, may be considered as a very valuable acquisition. Perhaps

NITROUS AIR might be still more efficacious. This species of factitious

air is obtained from all the metals except zinc, by means of the nitrous

acid; and Dr. Priestley informs me, that as a sweetener and antiseptic

it far surpasses fixed air. He put two mice into a quantity of it, one

just killed, the other offensively putrid. After twenty-five days they

were both perfectly sweet.

In the ULCEROUS SORE THROAT much advantage has been experienced from the

vapours of effervescing mixtures drawn into the _fauces_[17]. But this

remedy should not supersede the use of other antiseptic

applications.[18]

A physician[19] who had a very painful APTHOUS ULCER at the point of his

tongue, found great relief, when other remedies failed, from the

application of fixed air to the part affected. He held his tongue over

an effervescing mixture of potash and vinegar; and as the pain was

always mitigated, and generally removed by this vaporisation, he

repeated it, whenever the anguish arising from the ulcer was more than

usually severe. He tried a combination of potash and oil of vitriol well

diluted with water; but this proved stimulant and increased his pain;

probably owing to some particles of the acid thrown upon the tongue, by

the violence of the effervescence. For a paper stained with the purple

juice of radishes, when held at an equal distance over two vessels, the

one containing potash and vinegar, the other the same alkali and

_Spiritus vitrioli tenuis_, was unchanged by the former, but was spotted

with red, in various parts, by the latter.

In MALIGNANT FEVERS wines abounding with fixed air may be administered,

to check the septic ferment, and sweeten the putrid _colluvies_ in the

_primae viae_. If the laxative quality of such liquors be thought an

objection to the use of them, wines of a greater age may be given,

impregnated with mephitic air, by a simple but ingenious contrivance of

my friend Dr. Priestley.[20]

The patient's common drink might also be medicated in the same way. A

putrid DIARRH[OE]A frequently occurs in the latter stage of such

disorder, and it is a most alarming and dangerous symptom. If the

discharge be stopped by astringents, a putrid _fomes_ is retained in the

body, which aggravates the delirium and increases the fever. On the

contrary, if it be suffered to take its course, the strength of the

patient must soon be exhausted, and death unavoidably ensue. The

injection of mephitic air into the intestines, under these

circumstances, bids fair to be highly serviceable. And a case of this

deplorable kind, has lately been communicated to me, in which the vapour

of chalk and oil of vitriol conveyed into the body by the machine

employed for tobacco clysters, quickly restrained the _diarrhoea_,

corrected the heat and foetor of the stools, and in two days removed

every symptom of danger[21]. Two similar instances of the salutary

effects of mephitic air, thus administered, have occurred also in my own

practice, the history of which I shall briefly lay before the reader.

May we not presume that the same remedy would be equally useful in the

DYSENTERY? The experiment is at least worthy of trial.

Mr. W----, aged forty-four years, corpulent, inactive, with a short

neck, and addicted to habits of intemperance, was attacked on the 7th of

July 1772, with symptoms which seemed to threaten an apoplexy. On the

8th, a bilious looseness succeeded, with a profuse hoemorrhage from

the nose. On the 9th, I was called to his assistance. His countenance

was bloated, his eyes heavy, his skin hot, and his pulse hard, full, and

oppressed. The diarrhoea continued; his stools were bilious and very

offensive; and he complained of griping pains in his bowels. He had

lost, before I saw him, by the direction of Mr. Hall, a surgeon of

eminence in Manchester, eight ounces of blood from the arm, which was of

a lax texture; and he had taken a saline mixture every sixth hour. The

following draught was prescribed, and a dose of rhubarb directed to be

administered at night.

Rx. _Aq. Cinnam. ten._ oz. j.

_Succ. Limon. recent._ oz. ss.

_Salis Nitri gr. xij. Syr. e Succo Limon. dr. j. M. f. Haust._

_4tis horis sumendus._

July 11. The _Diarrhoea_ was more moderate; his griping pains were

abated; and he had less stupor and dejection in his countenance. Pulse

90, not so hard or oppressed. As his stools continued to be foetid,

the dose of rhubarb was repeated; and instead of simple cinnamon-water,

his draughts were prepared with an infusion of columbo root.

12. The _Diarrhoea_ continued; his stools were involuntary; and he

discharged in this way a quantity of black, grumous, and foetid blood.

Pulse hard and quick; skin hot; tongue covered with a dark fur; abdomen

swelled; great stupor. Ten grains of columbo root, and fifteen of the

_Gummi rubrum astringens_ were added to each draught. Fixed air, under

the form of clysters, was injected every second or third hour; and

directions were given to supply the patient plentifully with water,

artificially impregnated with mephitic air. A blister was also laid

between his shoulders.

13. The Diarrhoea continued, with frequent discharges of blood; but

the stools had now lost their foetor. Pulse 120; great flatulence in

the bowels, and fulness in the belly. The clysters of fixed air always

diminished the tension of the _Abdomen_, abated flatulence, and made the

patient more easy and composed for some time after their injection. They

were directed to be continued, together with the medicated water. The

nitre was omitted, and a scruple of the _Confect. Damocratis_ was given

every fourth hour, in an infusion of columbo root.

14. The Diarrhoea was how checked, His other symptoms continued as

before. Blisters were applied to the arms; and a drachm and a half of

the _Tinctura Serpentariae_ was added to each draught.

15. His pulse was feeble, quicker and more irregular. He dosed much;

talked incoherently; and laboured under a slight degree of _Dyspnaea_.

His urine, which had hitherto assumed no remarkable appearance, now

became pale. Though he discharged wind very freely, his belly was much

swelled, except for a short time after the injection of the

air-clysters. The following draughts were then prescribed.

Rx _Camphorae mucilag. G. Arab, solutae gr. viij. Infus. Rad.

Columbo oz. jfs Tinct. Serpent. dr. ij Confect. Card.

scruple j Syr. e Cort. Aurant dr. i m. f. Haust. 4tis horis

sumendus._

Directions were given to foment his feet frequently with vinegar and

warm water.

16. He has had no stools since the 14th. His _Abdomen_ is tense. No

change in the other symptoms. The _Tinct. Serpent._ was omitted in his

draughts, and an equal quantity of _Tinct. Rhaei Sp._ substituted in its

place.

In the evening he had a motion to stool, of which he was for the first

time so sensible, as to give notice to his attendants. But the

discharge, which was considerable and slightly offensive, consisted

almost entirely of blood, both in a coagulated and in a liquid state.

His medicines were therefore varied as follows:

Rx. _Decoct. Cort. Peruv. oz. iss Tinct. Cort. ejusd. dr. ij. Confect.

Card. scruple j Gum. Rubr. Astring. gr.

xv. Pulv. Alnmin. gr. vij. m. f. Haustus 4tis horis

sumendus._

Red Port wine was now given more freely in his medicated water; and his

nourishment consisted of sago and salep.

In this state, with very little variation, he continued for several

days; at one time ostive, and at another discharging small quantities of

faeces, mixed with grumous blood. The air-clysters were continued, and

the astringents omitted.

20. His urine was now of an amber colour, and deposited a slight

sediment. His pulse was more regular, and although still very quick,

abated in number ten strokes in a minute. His head was less confused,

and his sleep seemed to be refreshing. No blood appeared in his stools,

which were frequent, but small in quantity; and his _Abdomen_ was less

tense than usual. He was extremely deaf; but gave rational answers to

the few questions which were proposed to him; and said he felt no pain.

21. He passed a very restless night; his delirium recurred; his pulse

beat 125 strokes in a minute; his urine was of a deep amber colour when

first voided; but when cold assumed the appearance of cow's whey. The

_Abdomen_ was not very tense, nor had he any further discharge of blood.

Directions were given to shave his head, and to wash it with a mixture

of vinegar and brandy; the quantity of wine in his drink was diminished;

and the frequent use of the pediluvium was enjoined. The air-clysters

were discontinued, as his stools were not offensive, and his _Abdomen_

less distended.

22. His pulse was now small, irregular, and beat 130 strokes in a

minute. The _Dyspnoea_ was greatly increased; his skin was hot, and

bedewed with a clammy moisture; and every symptom seemed to indicate the

approach of death. In this state he continued till evening, when he

recruited a little. The next day he had several slight convulsions. His

urine which was voided plentifully, still put on the appearance of whey

when cold. Cordial and antispasmodic draughts, composed of camphor,

tincture of castor, and _Sp. vol. aromat._ were now directed; and wine

was liberally administered.

24. He rose from his bed, and by the assistance of his attendants walked

across the chamber. Soon after he was seized with a violent convulsion,

in which he expired.

To adduce a case which terminated fatally as a proof of the efficacy of

any medicine, recommended to the attention of the public, may perhaps

appear singular; but cannot be deemed absurd, when that remedy answered

the purposes for which it was intended. For in the instance before us;

fixed air was employed, not with an expectation that it would cure the

fever, but to obviate the symptoms of putrefaction, and to allay the

uneasy irritation in the bowels. The disease was too malignant, the

nervous system too violently affected, and the strength of the patient

too much exhausted by the discharges of blood which he suffered, to

afford hopes of recovery from the use of the most powerful antiseptics.

But in the succeeding case the event proved more fortunate.

Elizabeth Grundy, aged seventeen, was attacked on the 10th of December

1772, with the usual symptoms of a continued fever. The common method of

cure was pursued; but the disease increased, and soon assumed a putrid

type.

On the 23d I found her in a constant delirium, with a _subsultus

tendinum_. Her skin was hot and dry, her tongue black, her thirst

immoderate, and her stools frequent, extremely offensive, and for the

most part involuntary. Her pulse beat 130 strokes in a minute; she dosed

much; and was very deaf. I directed wine to be administered freely; a

blister to be applied to her back; the _pediluvium_ to be used several

times in the day; and mephitic air to be injected under the form of a

clyster every two hours. The next day her stools were less frequent, had

lost their foetor, and were no longer discharged involuntarily; her

pulse was reduced to 110 strokes in the minute; and her delirium was

much abated. Directions were given to repeat the clysters, and to supply

the patient liberally with wine. These means were assiduously pursued

several days; and the young woman was so recruited by the 28th, that the

injections were discontinued. She was now quite rational, and not averse

to medicine. A decoction of Peruvian bark was therefore prescribed, by

the use of which she speedily recovered her health.

I might add a third history of a putrid disease, in which the mephitic

air is now under trial, and which affords the strongest proof both of

the _antiseptic_, and of the _tonic_ powers of this remedy; but as the

issue of the case remains yet undetermined (though it is highly

probable, alas! that it will be fatal) I shall relate only a few

particulars of it. Master D. a boy of about twelve years of age, endowed

with an uncommon capacity, and with the most amiable dispositions, has

laboured many months under a hectic fever, the consequence of several

tumours in different parts of his body. Two of these tumours were laid

open by Mr. White, and a large quantity of purulent matter was

discharged from them. The wounds were very properly treated by this

skilful surgeon, and every suitable remedy, which my best judgment could

suggest, was assiduously administered. But the matter became sanious, of

a brown colour, and highly putrid. A _Diarrhoea_ succeeded; the

patient's stools were intolerably offensive, and voided without his

knowledge. A black fur collected about his teeth; his tongue was covered

with _Aphthae_; and his breath was so foetid, as scarcely to be

endured. His strength was almost exhausted; a _subsultus tendinum_ came

on; and the final period of his sufferings seemed to be rapidly

approaching. As a last, but almost hopeless, effort, I advised the

injection of clysters of mephitic air. These soon corrected the foetor

of the patient's stools; restrained his _Diarrhoea_; and seemed to

recruit his strength and spirits. Within the space of twenty-four hours

his wounds assumed a more favourable appearance; the matter discharged

from them became of a better colour and consistence; and was no longer

so offensive to the smell. The use of this remedy has been continued

several days, but is now laid aside. A large tumour is suddenly formed

under the right ear; swallowing is rendered difficult and painful; and

the patient refuses all food and medicine. Nourishing clysters are

directed; but it is to be feared that these will renew the looseness,

and that this amiable youth will quickly sink under his disorder[22].

The use of _wort_ from its saccharine quality, and disposition to

ferment, has lately been proposed as a remedy for the SEA SCURVY. Water

or other liquors, already abounding with fixed air in a separate state,

should seem to be better adapted to this purpose; as they will more

quickly correct the putrid disposition of the fluids, and at the same

time, by their gentle stimulus[23] increase the powers of digestion, and

give new strength to the whole system.

Dr. Priestley, who suggested both the idea and the means of executing

it, has under the sanction of the College of Physicians, proposed the

scheme to the Lords of the Admiralty, who have ordered trial to be made

of it, on board some of his Majesty's ships of war. Might it not however

give additional efficacy to this remedy, if instead of simple water, the

infusion of malt were to be employed?

I am persuaded such a medicinal drink might be prescribed also with

great advantage in SCROPHULOUS COMPLAINTS, when not attended with a

hectic fever; and in other disorders in which a general acrimony

prevails, and the crasis of the blood is destroyed. Under such

circumstances, I have seen _vibices_ which spread over the body,

disappear in a few days from the use of wort.

A gentleman who is subject to a scorbutic eruption in his face, for

which he has used a variety of remedies with no very beneficial effect,

has lately applied the fumes of chalk and oil of vitriol to the parts

affected. The operation occasions great itching and pricking in the

skin, and some degree of drowsiness, but evidently abates the serous

discharge, and diminishes the eruption. This patient has several

symptoms which indicate a genuine scorbutic DIATHESIS; and it is

probable that fixed air, taken internally, would be an useful medicine

in this case.

The saline draughts of Riverius are supposed to owe their antiemetic

effects to the air, which is separated from the salt of wormwood during

the act of effervescence. And the tonic powers of many mineral waters

seem to depend on this principle. I was lately desired to visit a lady

who had most severe convulsive REACHINGS. Various remedies had been

administered without effect, before I saw her. She earnestly desired a

draught of malt liquor, and was indulged with half a pint of Burton beer

in brisk effervescence. The vomitings ceased immediately, and returned

no more. Fermenting liquors, it is well known, abound with fixed air. To

this, and to the cordial quality of the beer, the favourable effect

which it produced, may justly be ascribed. But I shall exceed my design

by enlarging further on this subject. What has been advanced it is

hoped, will suffice to excite the attention of physicians to a remedy

which is capable of being applied to so many important medicinal

purposes.

NUMBER IV.

_Extract of a Letter from WILLIAM FALCONER, M.D. of BATH._

Jan 6, 1774,

Reverend Sir,

I once observed the same taste you mention (Philosophical Transactions,

p. 156. of this Volume, p. 35.) viz. like tar water, in some water that

I impregnated with fixed air about three years ago. I did not then know

to what to attribute it, but your experiment seems to clear it up. I

happened to have spent all my acid for raising effervescence, and to

supply its place I used a bottle of dulcified spirit of nitre, which I

knew was greatly under-saturated with spirit of wine; from which, as

analogous to your observation, I imagine the effect proceeded.

As[24] to the coagulation of the blood of animals by fixed Air, I fear

it will scarce stand the test of experiment, as I this day gave it, I

think, a fair trial, in the following manner.

A young healthy man, at 20 years old, received a contusion by a fall,

was instantly carried to a neighbouring surgeon, and, at my request,

bled in the following manner.

I inserted a glass funnel into the neck of a large clear phial about oz.

x. contents, and bled him into it to about oz. viii. By these means the

blood was exposed to the air as little a time as possible, as it flowed

into the bottle as it came from the orifice.

As soon as the quantity proposed was drawn, the bottle was carefully

corked, and brought to me. It was then quite fluid, nor was there the

least separation of its parts.

On the surface of this I conveyed several streams of fixed air (having

first placed the bottle with the blood in a bowl of water, heated as

nearly to the human heat as possible) from the mixture of the vitriolic

acid and lixiv. tartar, which I use preferably to other alkalines, as

being (as Dr. Cullen observes) in the mildest state, and therefore most

likely to generate most air.

I shook the phial often, and threw many streams of air on the blood, as

I have often practised with success for impregnating water; but could

not perceive the smallest signs of coagulation, although it stood in an

atmosphere of fixed air 20 minutes or more. I then uncorked the bottles,

and poured off about oz. ii to which I added about 6 or 7 gtts of spirit

of vitriol, which coagulated it immediately. I set the remainder in a

cold place and it coagulated, as near as I could judge, in the same time

that blood would have done newly drawn from the vein.

P. 82. Perhaps the circumilance of putrid vegetables yielding all fixed

and no inflammable air may be the causes of their proving so antiseptic,

even when putrid, as appears by Mr. Alexander's Experiments.

P. 86. Perhaps the putrid air continually exhaled may be one cause of

the luxuriancy of plants growing on dunghills or in very rich soils.

P. 146. Your observation that inflammable air consists of the union of

some acid vapour with phlogiston, puts me in mind of an old observation

of Dr. Cullen, that the oil separated from soap by an acid was much more

inflammable than before, resembling essential oil, and soluble in V. sp.

I have tried fixed air as an antiseptic taken in by respiration, but

with no great success. In one case it seemed to be of service, in two it

seemed indifferent, and in one was injurious, by exciting a cough.

NUMBER V.

_Extract of a Letter from Mr. WILLIAM BEWLEY, of GREAT MASSINGHAM,

NORFOLK._

March 23, 1774.

Dear Sir,

When I first received your paper, I happened to have a process going on

for the preparation of _nitrous ether_, without distillation.[25] I had

heretofore always taken for granted that the elastic fluid generated in

that preparation was _fixed_ air: but on examination I found this

combination of the nitrous acid with inflammable spirits, produced an

elastic fluid that had the same general properties with the air that you

unwillingly, though very properly, in my opinion, term _nitrous_; as I

believe it is not to be procured without employing the _nitrous_ acid,

either in a simple state, or compounded, as in _aqua regia_. I shall

suggest, however, by and by some doubts with respect to it's title to

the appellation of _air_.

Water impregnated with your nitrous air _certainly_, as you suspected

from it's taste, contains the nitrous acid. On saturating a quantity of

this water with a fixed alcali, and then evaporating, &c. I have

procured two chrystals of nitre. But the principal observations that

have occurred to me on the subject of nitrous air are the following. My

experiments have been few and made by snatches, under every disadvantage

as to apparatus, &c. and with frequent interruptions; and yet I think

they are to be depended upon.

My first remark is, that nitrous air does not give water a sensibly acid

impregnation, unless it comes into contact, or is mixed with a portion

of common or atmospherical air: and my second, that nitrous air

principally consists of the nitrous acid itself, reduced to the state of

a _permanent_ vapour not condensable by cold, like other vapours, but

which requires the presence and admixture of common air to restore it to

its primitive state of a liquid. I am beholden for this idea, you will

perceive, to your own very curious discovery of the true nature of Mr.

Cavendish's _marine_ vapour.

When I first repeated your experiment of impregnating water with nitrous

air, the water, I must own tasted acid; as it did in one, or perhaps two

trials afterwards; but, to my great astonishment, in all the following

experiments, though some part of the factitious air, or vapour, was

visibly absorbed by the water, I could not perceive the latter to have

acquired any sensible acidity. I at length found, however, that I could

render this same water _very_ acid, by means only of the nitrous air

already included in the phial with it. Taking the inverted phial out of

the water, I remove my finger from the mouth of it, to admit a little

of the common air, and instantly replace my finger. The redness,

effervescence, and diminution take place. Again taking off my finger,

and instantly replacing it, more common, air rushes in, and the same

phenomena recur. The process sometimes requires to be seven or eight

times repeated, before the whole of the nitrous _vapour_ (as I shall

venture to call it) is condensed into nitrous _acid_, by the successive

entrance of fresh parcels of common air after each effervescence; and

the water becomes evidently more and more acid after every such fresh

admission of the external air, which at length ceases to enter, when the

whole of the vapour has been condensed. No agitation of the water is

requisite, except a gentle motion, just sufficient to rince the sides of

the phial, in order to wash off the condensed vapour.

The acidity which you (and I likewise, at first) observed in the water

agitated with nitrous air _alone_, I account for thus. On bringing the

phial to the mouth, the common air meeting with the nitrous vapour in

the neck of the phial, condenses it, and impregnates the water with the

acid, in the very act of receiving it upon the tongue. On stopping the

mouth of the phial with my tongue for a short time and afterwards

withdrawing it a very little, to suffer the common air to rush past it

into the phial, the sensation of acidity has been sometimes intolerable:

but taking a large gulph of the water at the same time, it has been

found very slightly acid.--The following is one of the methods by which

I have given water a very strong acid impregnation, by means of a

mixture of nitrous and common air.

Into a small phial, containing only common air, I force a quantity of

nitrous air at random, out of a bladder, and instantly clap my finger on

the mouth of the bottle. I then immerse the neck of it into water, a

small quantity of which I suffer to enter, which squirts into it with

violence; and immediately replacing my finger, remove the phial. The

water contained in it is already _very_ acid, and it becomes more and

more so (if a sufficient quantity of nitrous air was at first thrown in)

on alternately stopping the mouth of the phial, and opening it, as often

as fresh air will enter.

Since I wrote the above, I have frequently converted a small portion of

water in an ounce phial into a weak _Aqua fortis_, by repeated mixtures

of common and nitrous air; throwing in alternately the one or the other,

according to the circumstances; that is, as long as there was a

superabundance of nitrous air, suffering the common air to enter and

condense it; and, when that was effected, forcing in more nitrous air

from the bladder, to the common air which now predominated in the

phial--and so alternately. I have wanted leisure, and conveniences, to

carry on this process to its _maximum_, or to execute it in a different

and better manner; but from what I have done, I think we may conclude

that nitrous air consists principally of the nitrous acid,

phlogisticated, or otherwise so modified, by a previous commenstruation

with metals, inflammable spirits, &c. as to be reduced into a durably

elastic vapour: and that, in order to deprive it of its elasticity, and

restore it to its former state, an addition of common air is requisite,

and, as I suspect, of water likewise, or some other fluid: as in the

course of my few trials, I have not yet been able to condense it in a

perfectly dry bottle.

NUMBER VI.

_A Letter from_ Dr. FRANKLIN.

Craven Street, April 10, 1774.

Dear Sir,

In compliance with your request, I have endeavoured to recollect the

circumstances of the American experiments I formerly mentioned to you,

of raising a flame on the surface of some waters there.

When I passed through New Jersey in 1764, I heard it several times

mentioned, that by applying a lighted candle near the surface of some of

their rivers, a sudden flame Would catch and spread on the water,

continuing to burn for near half a minute. But the accounts I received

were so imperfect that I could form no guess at the cause of such an

effect, and rather doubted the truth of it. I had no opportunity of

seeing the experiment; but calling to see a friend who happened to be

just returned home from making it himself, I learned from him the manner

of it; which was to choose a shallow place, where the bottom could be

reached by a walking-stick, and was muddy; the mud was first to be

stirred with the stick, and when a number of small bubbles began to

arise from it, the candle was applied. The flame was so sudden and so

strong, that it catched his ruffle and spoiled it, as I saw. New-Jersey

having many pine-trees in different parts of it, I then imagined that

something like a volatile oil of turpentine might be mixed with the

waters from a pine-swamp, but this supposition did not quite satisfy me.

I mentioned the fact to some philosophical friends on my return to

England, but it was not much attended to. I suppose I was thought a

little too credulous.

In 1765, the Reverend Dr. Chandler received a letter from Dr. Finley,

President of the College in that province, relating the same experiment.

It was read at the Royal Society, Nov. 21, of that year, but not printed

in the Transactions; perhaps because it was thought too strange to be

true, and some ridicule might be apprehended if any member should

attempt to repeat it in order to ascertain or refute it. The following

is a copy of that account.

"A worthy gentleman, who lives at a few miles distance, informed me that

in a certain small cove of a mill-pond, near his house, he was surprized

to see the surface of the water blaze like inflamed spirits. I soon

after went to the place, and made the experiment with the same success.

The bottom of the creek was muddy, and when stirred up, so as to cause a

considerable curl on the surface, and a lighted candle held within two

or three inches of it, the whole surface was in a blaze, as instantly as

the vapour of warm inflammable spirits, and continued, when strongly

agitated, for the space of several seconds. It was at first imagined to

be peculiar to that place; but upon trial it was soon found, that such a

bottom in other places exhibited the same phenomenon. The discovery was

accidentally made by one belonging to the mill."

I have tried the experiment twice here in England, but without success.

The first was in a slow running water with a muddy bottom. The second in

a stagnant water at the bottom of a deep ditch. Being some time employed

in stirring this water, I ascribed an intermitting fever, which seized

me a few days after, to my breathing too much of that foul air which I

stirred up from the bottom, and which I could not avoid while I stooped

in endeavouring to kindle it.--The discoveries you have lately made of

the manner in which inflammable air is in some cases produced, may throw

light on this experiment, and explain its succeeding in some cases, and

not in others. With the highest esteem and respect,

I am, Dear Sir,

Your most obedient humble servant,

B. FRANKLIN.

NUMBER VII.

_Extract of a Letter from_ Mr. HENRY _of_ Manchester.

It is with great pleasure I hear of your intended publication _on air_,

and I beg leave to communicate to you an experiment or two which I

lately made.

Dr. Percival had tried, without effect, to dissolve lead in water

impregnated with fixed air. I however thought it probable, that the

experiment might succeed with nitrous air. Into a quantity of water

impregnated with it, I put several pieces of sheet-lead, and suffered

them, after agitation, to continue immersed about two hours. A few drops

of vol. tincture of sulphur changed the water to a deep orange colour,

but not so deep as when the same tincture was added to a glass of the

same water, into which one drop of a solution of sugar of lead had been

instilled. The precipitates of both in the morning, were exactly of the

same kind; and the water in which the lead had been infused all night,

being again tried by the same test, gave signs of a still stronger

saturnine impregnation--Whether the nitrous air acts as an acid on the

lead, or in the same manner that fixed air dissolves iron, I do not

pretend to determine. Syrup of violets added to the nitrous water became

of a pale red, but on standing about an hour, grew of a turbid brown

cast.

Though the nitrous acid is not often found, except produced by art, yet

as there is a probability that nitre may be formed in the earth in large

towns, and indeed fossile nitre has been actually found in such

situations, it should be an additional caution against the use of leaden

pumps.

I tried to dissolve mercury by the same means, but without success.

I am, with the most sincere esteem,

Dear Sir,

Your obliged and obedient servant,

THO. HENRY.

_FINIS._

FOOTNOTES:

[15] See Dr. Falconer's very useful and ingenious treatise on the Bath

water, 2d edit. p. 313.

[16] May, 1772.

[17] Vid. Mr. White's useful treatise on the management of pregnant and

lying-in women, p. 279.

[18] See the author's observations on the efficacy of external

applications in the ulcerous sore throats, Essays medical and

experimental, Vol. I. 2d edit. p. 377.

[19] The author of these observations.

[20] Directions for impregnating water with fixed air, in order to

communicate to it the peculiar spirit and virtues of Pyrmont water, and

other mineral waters of a similar nature.

[21] Referring to the case communicated by Mr. Hey.

[22] He languished about a week, and then died.

[23] The vegetables which are most efficacious in the cure of the

scurvy, possess some degree of a stimulating power.

[24] This refers, to an experiment mentioned in the first publication of

these papers in the Philosophical Transactions, but omitted in this

volume.

[25] The first account of this curious process was, I believe, given in

the Mem. de l'Ac. de Sc. de Paris for 1742. Though seemingly less

volatile than the vitriolic ether, it boils with a much smaller degree

of heat. One day last summer, it boiled in the coolest room of my house;

as it gave me notice by the explosion attending its driving out the

cork. To save the bottle, and to prevent the total loss of the liquor by

evaporation, I found myself obliged instantly to carry it down to my

cellar.

ERRATA.

P. 15. l. 13. _for_ it to _read_ to it

p. 24. l. 20. ---- has ---- had

p. 60. l. 22. ---- inflammable ---- in inflammable

p. 84. l. 5. ---- experiments ---- experiment

p. 145. l. 16. ---- with ---- of

p. 153. l. 1. ---- that is ---- this air

p. 199. l. 17. ---- ingenious ---- ingenuous

p. 211. l. 23. ---- of ---- , if

p. 243. l. 27. ---- diminishing ---- diminished

p. 272. l. 21. ---- seem ---- seems

p. 301. l. 31. ---- ---- ---- one end

p. 303. l. 5. ---- ---- ---- the nitrous

p. 304. l. 21. ---- deslrium ---- delirium

p. 306. l. 2. ---- recet. ---- recent.

p. 308. l. 7. ---- per ---- Peruv.

p. 313. l. 27. ---- usual ---- useful

p. 300. to 314. passim ---- Diarrhaea ---- Diarrhoea

p. 316. l. 11. ---- remains ---- remainder

p. 524. l. 15. ---- it ---- iron.

A CATALOGUE of BOOKS written by

JOSEPH PRIESTLEY, LL.D. F.R.S.,

_And printed for_

J. JOHNSON, BOOKSELLER, at No. 72,

St. Paul's Church-Yard, London.

1. The HISTORY and PRESENT STATE of ELECTRICITY, with original

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THE THEOLOGICAL REPOSITORY.

Consisting of original Essays, Hints, Queries, &c. calculated to

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[Illustration: _To face the last page._]