Cursory thoughts on the advantages of Biography.--Plan
and objects of the Pneumatic Institution.--Davy contracts
friendships during his residence at Bristol.--His first visit
to London.--His Letters to Mr. Davies Gilbert.--The publication
of the West Country Contributions, by Dr. Beddoes.--Davy's
Essays on Heat, Light, and Respiration.--His interesting
experiments on bonnet canes.--He commences an enquiry into
the nature of nitrous oxyd.--He publishes his chemical
researches.--A critical examination of the work.--Testimony of
Tobin, Clayfield, Southey, and others, respecting the powers
of nitrous oxyd.--Davy breathes carburetted hydrogen gas, and
nearly perishes from its effects.--His new Galvanic experiments
communicated in a Letter to Mr. Gilbert.
Having concluded the early history of the subject of these
memoirs, and conducted it to that memorable day on which he left
his native town, and bursting from obscurity, prepared to enter
upon a wider field of usefulness and honour, I shall accompany
him in his progress; and with the honest desire of affording
instruction as well as amusement,--for history is useful only as it
holds up the mirror of Truth,--I shall continue to point out the
various circumstances that may have contributed to his success and
scientific renown; and to offer such occasional reflections as may
be likely to illustrate not only the superficial peculiarities
which constitute the light and shade of character, but those deeper
varieties of mind, upon which the superiority of intellect may be
supposed to depend.
After all, the great end of biography is not to be found, as some
would seem to imagine, in a series of dates, or in a collection
of gossiping anecdotes and table-talk, which, instead of lighting
up and vivifying the features, hang as a cloud of dust upon the
portrait; but it is to be found in an analysis of human genius, and
in the developement of those elements of the mind, to whose varied
combinations, and nicely adjusted proportions, the mental habits,
and intellectual peculiarities of distinguished men may be readily
referred.
It has been stated that an arrangement had been concluded between
Dr. Beddoes and Davy: it is but an act of justice to say, that it
was of a liberal and honourable description; and let me also add in
this place, that no sooner had Davy found himself in a situation
which secured for him the necessaries of life, than he renounced
all claims upon his paternal property, in favour of his mother and
sisters.
By acceding to the proposal of Dr. Beddoes, he never intended to
abandon the profession in which he had embarked; on the contrary,
he persevered in his determination to study and graduate at
Edinburgh, and his patron promised that every opportunity should be
afforded him at Bristol for seeing medical practice: this part of
the arrangement, however, was voluntarily abandoned by him, for he
soon became so absorbed by the labours of the laboratory, as to
leave little leisure for the clinical studies of the hospital.
The Pneumatic Institution was established for the purpose of
investigating the medical powers of factitious airs or gases; and
to Davy was assigned the office of superintending the various
experiments.
It is now generally acknowledged, that the Art of Physic has not
derived any direct advantage from the application of a class of
agents which, undoubtedly, held forth the fairest promise of
benefit; but it is too frequently the case, that in physic, theory
and experience are in open hostilities with each other. The gases
are now never employed in the treatment of disease, except by a
few crafty or ignorant empirics, whose business it is to enrich
themselves by playing on the credulity of mankind: indeed, we may
say of popular remedies in general what M. de Lagrange has so
wittily said of popular prejudices, that they are the cast-off
clothes of philosophers, in which the rabble dress themselves.
The investigation, however, into the nature and composition of
the gases paved the way to some new and important discoveries in
science; so that, to borrow a Baconian metaphor, although our
philosophers failed in obtaining the treasure for which they so
eagerly dug, they at least, by turning up and pulverizing the soil,
rendered it fertile. The ingenuity of the chemist will for ever
remain on record; the phantoms of the physicians have vanished into
air.
Davy was now constantly engaged in the prosecution of new
experiments, in the conception of which, as he himself informs us,
he was greatly aided by the conversation and advice of Dr. Beddoes.
He was also occasionally assisted by Mr. William Clayfield, a
gentleman ardently attached to chemical pursuits, and whose name is
not unknown in the annals of science; indeed, it appears that to
him he was indebted for the invention of a mercurial air-holder,
by which he was enabled to collect and measure the various gases
submitted to examination. He had also the advantages of some
society of a highly intellectual cast: it is sufficient to mention
the names of Edgeworth and James Tobin.
In reply to a letter of enquiry which was lately addressed to her,
Miss Edgeworth observes, that "her father possessed much influence
over Davy's mind;" and that "when he was a very young man at
Clifton, unknown to fame, Mr. Edgeworth early distinguished and
warmly admired his talents, and gave him much counsel, which sunk
deep into his mind."
The present Lord Durham and his brother were also resident in the
house of Dr. Beddoes, not only for their education, but for the
benefit of his professional superintendence. Besides those who
were residing at Clifton, the most distinguished in the circles
of science and literature paid passing visits to Dr. Beddoes;
with many of whom Davy contracted an acquaintance, with some an
intimacy, and with a few a solid and permanent friendship. In
examining the individuals composing this latter class, we find them
differing so widely from each other in character and pursuit, that
we are led to enquire upon what principles of affinity his regards
could possibly have been attracted--the truth is, that there was
more than one avenue to his heart; and the philosopher, the poet,
the physician, the philanthropist, and the sportsman, found each,
upon different terms, a more or less ready access to its recesses.
The chemist who would aspire to his favour, could alone obtain it
by laborious application and novel research; the philanthropist,
by the practicability of his schemes for improving society, and
increasing the sum of its happiness; but the fisherman instantly
caught his affections by a hook and line. To be a fly-fisher
was, in his opinion, to possess the capabilities of intellectual
distinction, although circumstances might not have conspired to
call them into action; whilst a proficiency in this art, when
exhibited by an individual otherwise distinguished, gave him an
additional claim to his attention and regard. The stern courage
of Nelson, tempered as it was with all the kindly feelings of
humanity, was sufficient to excite in the breast of Davy the most
enthusiastic admiration; but the circumstance of his having been
a fly-fisher, and continued the sport, even with his left hand,
threw, in his opinion, a still brighter halo around his character.
No one who knew him can accuse him of inconstancy in his
friendships: amidst the excitements of his station, and the
abstractions incident to his pursuits, he might not always have
shown those little attentions which are received by the world as
the indications of personal regard; but his heart beat not less
warmly on that account: when the flame of affection had been
once kindled, it burnt with a pure and steady light through life.
This will be readily seen in the letters addressed to his several
early friends, more especially to Mr. Poole of Nether Stowey, in
Somersetshire, and to Mr. Clayfield of Bristol, from which I shall
have occasion to present some interesting extracts.
Those who had become acquainted with him in early life, and were
enabled to watch the whole progress of his career from obscurity to
the highest pinnacle of fame, have declared that his extraordinary
talents never at any period excited greater astonishment and
admiration than during his short residence at Bristol. His
simplicity of mind and manner was also at this time truly
delightful. He scarcely knew the names of our best authors, much
less read any of their works; yet upon topics of moral philosophy
and metaphysics he would enter into discussion with acknowledged
scholars, and not only delight them with the native energy of
his mind, but instruct them by the novelty and truth of his
conceptions. Mr. Coleridge lately expressed to me the astonishment
he felt, very shortly after his introduction to him, on hearing him
maintain an argument upon some abstruse subject with a gentleman
equally distinguished for the extent of his erudition, and for the
talent of rendering it available for illustration;--the contrast
was most striking--it was the fresh and native wild flower, opposed
to the elaborate exotic of the _Hortus Siccus_!
During this period he occasionally visited his friend Mr. Gregory
Watt, at Birmingham; at which place his ambition was constantly
excited by intercourse with congenial minds; and his letters to his
mother and relations represent him as rejoicing in the success of
his experiments, and as delighting in his association with kindred
genius; but always casting a longing, lingering thought on the
scenes of his boyhood, he spoke with joyful anticipation of the
period at which he proposed to revisit his mother and family.
That he still continued to regard the practice of physic as the
great end and object of all his pursuits, is evident from one of
these letters, written in 1799, in which he says, "Philosophy,
Chemistry, and Medicine, are my profession."
On the 1st of December 1799 he visited London for the first
time, and remained about a fortnight; the friends with whom he
associated upon this occasion were Coleridge, Southey, Gregory
Watt, Underwood, James and John Tobin, Thomson, and Clayfield; all
of whom vied with each other in their exertions to render his visit
agreeable, conducting him to such persons and places as were deemed
worthy of his notice.
Of all the letters placed at my disposal, those addressed to his
early friend and patron, Mr. Davies Gilbert, are, in my judgment,
the most interesting: it is true, that as specimens of epistolary
style they have but slender pretensions, and are far less pleasing
than those written to Mr. Poole and others, in later life; but let
it be remembered that, as yet, their writer had never enjoyed the
advantages of literary correspondence. For the defects, however,
of style, there is more than sufficient compensation; they speak
from the heart;--they carry with them internal evidence of the
honest simplicity of his mind, and they throw a light upon the
peculiarities of his genius, which without such aid might be less
perfectly understood; above all, they evince an ardour which no
difficulties could repress, and a confidence which no failures
could extinguish. We clearly discern from his first letters, that
he entered upon his career of experiment with an almost chivalrous
feeling, flushed with the consciousness of native strength, and
exulting in the prospect of destined achievements.
I am aware that there are those who still object, with Dr. Sprat,
to the practice of publishing letters which were never intended for
the public eye, and I experience the inconvenience, while I respect
the delicacy, of such an opinion. I confess, on my own part, I have
always considered, with Mr. Mason, that the objections urged by the
learned historian of the Royal Society are wholly untenable. He
talks of "the souls of men thus appearing undressed, or in a habit
too negligent to go abroad in the streets, although they might be
seen by a few in a chamber." But the undress he would condemn,
is the nakedness of Truth--the negligent attire, the simple and
unadorned expression of those natural and significant traits,
whose value incomparably exceeds the premeditated and artificial
exhibitions of mind and manner. "_Nam in ingenio quoque sicut in
agro, quanquam alia diu serantur atque elaborantur, gratiora tamen
quæ sua sponte nascuntur._"[18]
[18] Dialogus de Oratoribus,--_Tacit._
I cannot but suspect that Dr. Sprat was, upon this occasion, more
anxious to display a metaphor, than to illustrate a truth. I have
often thought a very curious book might be written to show how
greatly, both in physics and in morals, the progress of truth
has been retarded, and the judgment of men warped, by the abuse
of metaphors; the most correct of which can be nothing more than
the image of Truth reflected, as it were, from a mirror, and
consequently liable to all the delusions of our mental optics. The
figure by which Nature was represented as "_abhorring a vacuum_,"
kept us in ignorance of the true theory of the pump for two
thousand years after the discovery of the weight, or gravity, of
the atmosphere;[19] and the unfortunate P. L. Courier positively
owed his conviction to a metaphor in the Judge's charge--"_Un écrìt
plein de poison._"--Well might the defendant exclaim, "_Sauvez-nous
de la Metaphore!_"
[19] Plutarch, in expressing the opinion of Asclepiades upon this
subject, represents him as saying, that the external air, _by
its weight_, opened its way with force into the breast. Seneca
also was acquainted with the weight and elastic force of the air;
for he describes the constant effort by which it expands itself
when it is compressed, and affirms that it has the property of
condensing itself, and of forcing its way through all obstacles
that oppose its passage.--Quæst. Nat. lib. v. c. v. and vi.
The first of the letters to which I have alluded appears to have
been written rather more than five weeks after his arrival at
Clifton.
TO DAVIES GIDDY, ESQ.
Clifton, November 12, 1798.
DEAR SIR,
I have purposely delayed writing until I could communicate to
you some intelligence of importance concerning the Pneumatic
Institution. The speedy execution of the plan will, I think,
interest you, both as a subscriber and a friend to science and
mankind. The present subscription is, we suppose, nearly adequate
to the purpose of investigating the medicinal powers of factitious
airs; it still continues to increase, and we may hope for the
ability of pursuing the investigation to its full extent. We are
negotiating for a house in Dowrie Square, the proximity of which to
Bristol, and its general situation and advantages, render it very
suitable to the purpose. The funds will, I suppose, enable us to
provide for eight or ten patients in the hospital, and for as many
out of it as we can procure.
We shall try the gases in every possible way. They may be condensed
by pressure and rarefied by heat. _Quere_,--would not a powerful
injecting syringe,[20] furnished with two valves, one opening into
an air-holder and the other into the breathing chamber, answer
the purpose of compression better than any other apparatus? Can
you not, from your extensive stores of philosophy, furnish us
with some hints on this subject? May not the non-respirable gases
furnish a class of different stimuli? of which the _oxymuriatic
acid gas_ would stand the highest, if we might judge from its
effects on the lungs; then, probably, _gaseous oxyd of azote_, and
_hydro-carbonate_.
I suppose you have not heard of the discovery of the native
_sulphate of strontian_ in England. I shall perhaps surprise you by
stating that we have it in large quantities here. It had long been
mistaken for _sulphate of barytes_, till our friend Clayfield,
on endeavouring to procure the _muriate of barytes_ from it by
decomposition, detected the strontian. We opened a fine vein of it
about a fortnight ago, at the Old Passage near the mouth of the
Severn. It was embodied in limestone and gypsum, the outside of
the vein, a striated mass; the internal parts finely crystallized
in cubes, of the Sp. Gr. 4·1. Clayfield has been working at it for
some time. We have persuaded him to publish his analysis in the
first volume of the Western Physical Collection.
I have made with him the phosphuret of barytes and of strontian:
they possess, in common with that of lime, the property of
producing phosphorized hydrogen gas; the phosphuret of strontian,
it appears, in a more eminent degree.
We have likewise attempted to decompose the boracic and muriatic
acids, by passing phosphorus, in vapour, through muriate, and
borate of lime, heated red. Phosphate of lime was found in the
experiment on the boracic acid; but, as no pneumatic apparatus was
employed, the experiment was uncertain. We shall repeat them next
week.
We are printing in Bristol the first volume of the 'West Country
Collection,' which will, I suppose, be out in the beginning of
January.
Mrs. Beddoes hopes that Miss Giddy received her letter, and desires
me to certify that she wrote almost immediately after the reception
of her epistle. She is as good, amiable, and elegant as when you
saw her. Believe me, dear Sir, with affection and respect,
Truly your's,
HUMPHRY DAVY.
[20] Here the reader will recognise the force of early
associations.
The work announced in the above letter was published in the
commencement of the year 1799, under the title of "Contributions
to Physical and Medical Knowledge, principally from the West of
England; collected by Thomas Beddoes, M.D."
The first two hundred pages, constituting very nearly half the
volume, are the composition of Davy, and consist of essays "On
Heat, Light, and the Combinations of Light." "On Phos-oxygen, or
Oxygen and its Combinations;" and "On the Theory of Respiration."
His first essay commences with an experiment, in order to show that
light is not, as Lavoisier supposed, a modification, or an effect,
of heat, but matter of a peculiar kind, _sui generis_, which, when
moving through space, or in a state of projection, is capable of
becoming the source of a numerous class of our sensations.
A small gunlock was armed with an excellent flint, and, on being
snapped in an exhausted receiver, did not produce any light. The
experiment was repeated in carbonic acid, and with a similar
result. Small particles were in each case separated from the steel,
which, on microscopic examination, evidently appeared to have
undergone fusion. Whence Davy argued, that light cannot be caloric
in a state of projection, or it must have been produced in these
experiments, where heat existed to an extent sufficient to fuse
steel. Nor, that it can be, as some have supposed, a vibration of
the imaginary fluid ether; for, granting the existence of such a
fluid, it must have been present in the receiver. If, then, light
be neither caloric in a state of projection, nor the vibration of
an imaginary ether, it must, he says, be a substance _sui generis_.
With regard to caloric, his opinion that it is not, like light,
material, has been already noticed. In the present essay he
maintains the proposition by the same method of reasoning as that
by which he attempts to establish the materiality of light, and
which mathematicians have termed the "_reductio ad absurdum_."
In his chapter on "Light and its Combinations," he indulges in
speculations of the wildest nature, although it must be confessed
that he has infused an interest into them which might almost be
called dramatic. They are certainly highly characteristic of that
enlightened fancy, which was perpetually on the wing, and whose
flight, when afterwards tempered and directed by judgment, enabled
him to abstract the richest treasures from the recesses of abstract
truth.
Taking it for granted that caloric has no existence as a material
body, or, in other words, that the phenomena of repulsion do not
depend upon the agency of a peculiar fluid, and that, on the
contrary, light is a subtle fluid acting on our organs of vision
_only when in a state of repulsive projection_, he proceeds to
examine the French theory of combustion; the defects of which he
considers to arise from the assumption of the imaginary fluid
_caloric_, and the total neglect of _light_. He conceives that
the light evolved during combustion previously existed in the
oxygen gas, which he therefore proposes for the future to call
PHOS-OXYGEN.[21]
[21] Brugnatelli considered that oxygen, in certain cases of
combination, entered into union with different bodies, without
parting with its _caloric_; and in that state he gave it the
name of THERM-OXYGEN; so that Davy had a precedent for his
nomenclatural innovation.
In following up this question, he would seem to consider Light
as the _Anima Mundi_, diffusing through the universe not only
organization, but even animation and perception.
_Phos-oxygen_ he considers as capable of combining with
additional proportions of Light, and of thus becoming '_luminated
Phos-oxygen!_'--from the decomposition of which, and the consequent
liberation of light, he seeks to explain many of the most recondite
phenomena of Nature.
We cannot but admire the eagerness with which he enlists known
facts into his service, and the boldness with which he ranges
the wilds of creation in search of analogies for the support and
illustration of his views. He imagines that the _Phos-oxygen_,
when thus _luminated_, must necessarily have its specific gravity
considerably diminished by the combination, and that it will
therefore occupy the higher regions of the atmosphere; hence, he
says, it is that combustion takes place at the tops of mountains
at a lower temperature than in the plains, and with a greater
liberation of light. The hydrogen which is disengaged from the
surface of the earth, he supposes, will rise until it comes into
contact with this _luminated Phos-oxygen_, when, by its attracting
the oxygen to form water, the light will be set free, and give
origin to the phenomena of fiery meteors at a great altitude.
The phenomenon termed '_Phosphorescence_,' or that luminous
appearance which certain bodies exhibit after exposure to heat, is
attributed by this theory to the light, which may be supposed
to quit such substances as soon as its particles have acquired
repulsive motion by elevation of temperature.
The Electric Fluid is considered as Light in a condensed state,
or, in other words, in that peculiar state in which it is not
supplied with a repulsive motion sufficiently energetic to impart
projection to its particles; for, he observes, that its chemical
action upon bodies is similar to that of Light; and when supplied
with repulsive motion by friction, or by the contact of bodies from
which it is capable of subtracting it, it loses the projectile
form, and becomes perceptible as Light. It is extremely probable,
he adds, that the great quantity of this fluid almost everywhere
diffused over our earth is produced by the condensation of Light,
in consequence of the subtraction of its repulsive motion by black
and dark bodies; while it may again recover the projectile force
by the repulsive motion of the poles, caused by the revolution
of the earth on its axis, and thus appear again in the state of
sensible light; and hence the phenomenon of the _Aurora Borealis_,
or Northern Lights.
In considering the theory of Respiration, he supposes that
_phos-oxygen_ combines with the venous blood without decomposition;
but that, on reaching the brain, the light is liberated in the form
of Electricity, which he believes to be identical with the nervous
fluid. On this supposition, sensations and ideas are nothing more
than motions of the nervous ether; or light exciting the medullary
substance of the nerves and brain into sensitive action!
He thinks it would be worth while to try, by a very sensible
electrometer, whether an insulated muscle, when stimulated into
action, would not give indications of the liberation of electric
fluid, although he suspects that in man the quantity is probably
too small, and too slowly liberated, to be ascertainable. In the
torpedo, and in some other animals, however, it is unquestionably
given out perceptibly during animal action.
When any considerable change takes place in the organic matter
of the body, so as to destroy the powers of life, new chemical
attractions and repulsive motions take place, and the different
principles of which the body is composed enter into new
combinations. In this process, which is called putrefaction, Davy,
in pursuance of this theory, thinks that in land-animals the latent
light of the system enters into new combinations with oxygen and
nitrogen, but that in fish no such combinations occur, and hence
the luminous appearance which accompanies their putrefaction.
Such is the outline of these extraordinary Essays. They stand upon
record, and therefore, as a faithful biographer, I was bound to
notice them; nor are they devoid of interest or instruction: I am
not quite sure that, amidst all the meteors of his fancy, there may
not be a gleam of truth. I allude to his theory of Respiration: it
certainly does not square aôwith the physiological opinions of the
day; nor did that of Newton, when he conjectured that water might
contain an inflammable element; but it was the refraction of a
great truth, at that time below the horizon.
It was a very ancient opinion, that life, being in its own
nature aëriform, is under the necessity of renewing itself by
inspiring the air. Modern chemistry, by teaching us the nature
of the atmosphere, has dispelled many fanciful theories of its
action, but it has not yet explained why respiration, the first
and last act of life,[22] cannot be suspended, even for a minute,
without the extinction of vitality. When we reflect upon this
fact, it is scarcely possible not to believe that the function has
been ordained for some greater purpose than that of removing a
portion of carbon from the circulating blood. Is it unreasonable
to conclude that some principle is thus imparted, which is too
subtle to be long retained in our vessels, and too important to
be dispensed with, even for the shortest period? "I offer this
opinion," as Montaigne says, "not as being good, but as being my
own."
[22] Breath and life are synonymous. In the Greek, the most
philosophically constructed language with which we are
acquainted, this _first_ and _last_ act is expressed by a verb
composed of alpha and omega--[Greek: aô]. In the Latin, the
connexion between _spiro_ and _spiritus_, breath and life, is
evident.
By these observations, I am not to be supposed as wishing, for a
moment, to uphold the wild hypotheses which I have just related; it
must be admitted that the theory of _phos-oxygen_ and _luminated
phos-oxygen_ has scarcely a parallel in extravagance and absurdity;
and I happen to know that, in after life, Davy bitterly regretted
that he had so committed himself; any allusion to the subject became
a source of painful irritation. It is to be remarked, that in every
course of lectures, although Davy did not refer to these theories,
he frequently alluded to the unphilosophic spirit that had given
origin to them; as if he had imposed upon himself this penance
as an atonement for his early follies. The following note
was taken at one of his lectures:--"After what has been said, it
will be useless to enter upon an examination of any of those
theories, which, assuming for their foundation the connexion of life
with respiration, have attempted to prove that oxygen is the
principle of life, and that the wonderful and mysterious
phenomena of perception arise from the action of common gravitating
substances upon each other. Such theories are the dreams of misemployed
genius, which the light of experiment and observation has
never conducted to truth, and are merely a collection of terms
derived from known phenomena, and applied by loose analogies
of language to unknown things."
The reader, however, will be disposed to treat him with all
tenderness when he remembers that the author of these Essays was
barely eighteen years of age. If blame is to fall on any one,
let it fall on Dr. Beddoes, who never should have sanctioned the
publication: had he curbed the ardent and untamed imagination of
the young philosopher, he would have acted the part of a wise
man and of a kind friend. But the truth is, that much as Davy
needed the bridle, Beddoes[23] required it still more; for,
notwithstanding his talents, he was as little fitted for a Mentor
as a weathercock for a compass; and had it not been for the
ascendency which Davy gained over his mind, the ardour of his
temperament would have continually urged him beyond the bounds of
reason.
[23] The only pun Davy is said to have ever made was upon the
occasion of Mr. Sadler being appointed by Dr. Beddoes as his
successor. "I cannot imagine," said he, "why he has engaged
_Sadler_, unless it is that he may be well _bridled_."
Caught by the loosest analogies, he would arrive at a conclusion
without examining all the conditions of his problem. In the
exercise of his profession, therefore, he was frequently led to
prescribe plans which he felt it necessary to retract the next
hour. His friend Mr. T---- had occasion to consult him upon the
case of his wife: the Doctor prescribed a new remedy; but, in the
course of the day he returned in haste, and begged that, before
Mrs. T---- took the medicine, its effect might be tried on a dog!
The following anecdote, which was lately communicated to me by
Mr. Coleridge, will not only illustrate a trait of character, but
furnish a salutary lesson to the credulous patron of empirics. As
soon as the powers of nitrous oxide were discovered, Dr. Beddoes
at once concluded that it must necessarily be a specific for
paralysis. A patient was selected for the trial, and the management
of it was entrusted to Davy. Previous to the administration of the
gas, he inserted a small pocket thermometer under the tongue of
the patient, as he was accustomed to do upon such occasions, to
ascertain the degree of animal temperature, with a view to future
comparison. The paralytic man, wholly ignorant of the nature of
the process to which he was to submit, but deeply impressed, from
the representations of Dr. Beddoes, with the certainty of its
success, no sooner felt the thermometer between his teeth than
he concluded that the _talisman_ was in full operation, and in
a burst of enthusiasm declared that he already experienced the
effects of its benign influence throughout his whole body:--the
opportunity was too tempting to be lost--Davy cast an intelligent
glance at Mr. Coleridge, and desired the patient to renew his visit
on the following day, when the same ceremony was again performed,
and repeated every succeeding day for a fortnight, the patient
gradually improving during that period, when he was dismissed as
cured, no other application having been used than that of the
thermometer. Dr. Beddoes, from whom the circumstances of the case
had been intentionally concealed, saw in the restoration of the
patient the confirmation of his opinion, and the fulfilment of
his most ardent hope--Nitrous Oxide was a specific remedy for
Paralysis! "It were criminal to retard the general promulgation of
so important a discovery; it were cruel to delay the communication
of the fact until the publication of another volume of his
'_Contributions_;' the periodical magazines were too slow in their
rate of travelling,--a flying pamphlet would be more expeditious;
paragraphs in the newspapers; circulars to the hospitals:"--such
were the reflections and plans which successively agitated the
physician's mind, when his eyes were opened to the unwelcome truth
by Davy's confessing the delusion that had been practised.
A short time after the publication of the first volume of the
"Contributions," Davy addressed to his friend the following
letter:--
TO DAVIES GIDDY, ESQ.
Clifton, Feb. 22, 1799.
DEAR FRIEND,--for I love you too well to call you by a more
ceremonious name,--I have delayed writing to you from day to day,
expecting that some of our experiments would produce results worthy
of communication. Since I received your last very acceptable
letter, I have been chiefly employed in pursuing the experiments on
Heat, Light, Respiration, &c. Of these experiments I shall give you
no account, as you will see them in print. I sent you a copy of my
Essays last week; if you have not received them, I trust you will
find them at my mother's, or at Mr. Tonkin's.
In the same parcel were two small packets, one from Mrs. Beddoes
for your father, the other for Miss Giddy from Mrs. Willoughby.
About a fortnight ago I sent a few chemical instruments to Mr.
Penneck of Penzance; and inclosed with them were specimens of the
different varieties of sulphate of strontian addressed to you. If
you have not received them, you will get them by sending to Mr.
Penneck.
On looking over a box of minerals last week, which was sent to
Dr. Beddoes from Cumberland, I found two very fine specimens of
sulphate of strontian, marked by the collector _Laminated Shorl_. I
suspect this mineral is not scarce in calcareous countries; it is,
I dare say, often mistaken for sulphate of barytes.
I have succeeded in combining strontian with the oxygenated
muriatic acid. This salt possesses most astonishing properties;[24]
you will find an account of them in my Essay.
When you have perused my papers, I shall be very much obliged to
you for a criticism upon them. When I left Penzance, I was quite an
infant in speculation,--I knew very little of Light or Heat. I am
now as much convinced of the non-existence of caloric, as I am of
the existence of light. Independent of the experiments which appear
to demonstrate its non-existence directly, and of which you will
find an account in my Essay, the consideration of certain phenomena
leads me to suppose that there would be no difficulty in proving
its non-existence by reasoning. These considerations have occurred
to me since the publication of the work. I could now render it much
more perfect; but I hope soon to complete the investigation of the
combinations of Light, and to produce a much more perfect work on
the subject. I shall be infinitely obliged to you for any hints
or observations, as far as the detection of errors of any kind,
for it is no flattery to say that I pay greater deference to your
opinion than to that of any other philosopher.
We intend next week to endeavour to ascertain, by the aid of a
delicate balance, the quantities of Light liberated in different
combustive processes. That there is a deficiency of weight, I am
convinced from many experiments.
The experiments on Light, &c. have prevented me from attempting
the decomposition of the undecompounded acids. We have ordered an
apparatus at the glass-house for this purpose, and I hope next
week we shall be able to carry on the investigation. Two modes
of effecting these decompositions have occurred to me:--first,
to bring phosphorus or sulphur, in the gaseous state, in contact
with the acid gases in a tube heated intensely; secondly, to send
sulphur in the gaseous state through muriate of copper or lead,
heated white. The attraction of sulphur for oxygen, of copper
for oxygen, and of sulphur for copper, will probably effect the
decomposition.
Our laboratory in the Pneumatic Institution is nearly finished, and
we shall begin the investigations in about a fortnight. We shall
begin by trying the gases in their simplest mode of application,
and gradually carry on the more complex processes.
I hope the gaseous oxide of azote will prove to be a specific
stimulus for the absorbents.
I was last week surprised by a letter from Mr. Watt, announcing
the success of their trial. When I was at Birmingham five weeks
ago, the family were in very low spirits. I spent nine or ten
days there, chiefly with Mr. Keir and Mr. Watt: I had a great
deal of chemical conversation with them. Mr. Keir is one of the
best-informed men I have ever met with, and extremely agreeable.
Both he and Mr. Watt are still phlogitians; but Mr. Keir altogether
disbelieves the doctrine of _calorique_.
What news have you in Cornwall? Has Mr. John Hawkins returned to
his native county? he will doubtless be a great acquisition to you.
Pray do you know whether the Zoophyta and marine worms are
susceptible of the galvanic stimulus? Experiments on them would
go far to determine whether the irritable or sensitive fibre is
primarily affected.
I know of little general scientific news. In the last volume of the
_Annales de Chimie_ is a curious paper by Berthollet on sulphurated
hydrogen: he makes it out to be an acid. I shall most anxiously
expect a letter from you, and I remain with affection and respect,
Yours,
HUMPHRY DAVY.
[24] The following is the account given in his Essay. "When
sulphuric acid was poured into a solution of this salt in water,
a beautiful and unexpected phenomenon took place. The room was
accidentally darkened at the moment this experiment was made, so
that we were enabled to perceive a vivid luminous appearance.
This experiment, independent of its beauty, is extremely pleasing
as affording an instance of true combustion, that is, the
production of Light and Heat by the mixture of two incombustible
bodies." It may be presumed, that this phenomenon arose from the
developement and decomposition of a portion of Euchlorine, a
compound which he subsequently discovered in 1811. In the year
1813, Chevreul announced, as a new discovery, that if strontian
be heated in contact with muriatic acid gas, the gas is absorbed,
and the earthy salt becomes red hot.--_See Annals of Philosophy_,
vol. ii. p. 312.
The letter which follows may be considered as a reply to one
received from Mr. Davies Gilbert, which, it would appear, contained
strictures upon his recently published Essays.
TO DAVIES GIDDY, ESQ.
April 10, 1799.
MY DEAR FRIEND,
The engagements resulting from the establishment of the Pneumatic
Institution, and from a course of experiments, to which I have
been obliged to pay great attention, have prevented me from
acknowledging to you my obligations for the very great pleasure I
received from your last excellent letter.
In experiments on Light and Heat, we have to deal with agents whose
changes we are unable directly to estimate. The most we can hope
for is such an arrangement of facts as will account for most of the
phenomena.
The supposition of active powers common to all matter, from
the different modifications of which all the phenomena of its
changes result, appears to me more reasonable than the assumption
of certain imaginary fluids alone endowed with active powers,
and bearing the same relation to common matter, as the vulgar
philosophy supposes spirit to bear to matter.
That the particles of bodies must move, or separate from each
other, when they become expanded, is certain. A repulsive motion of
the particles is directly the cause of expansion; and when bodies
are expanded by friction, under circumstances in which there could
be no heat communicated by bodies in contact, no oxidation and
no diminution of capacity, I see no difficulty in conceiving the
repulsive motion generated by the mechanical motion.
Your excellent and truly philosophic observations will induce me to
pay greater attention to all my positions. It is only by forming
theories, and then comparing them with facts, that we can hope to
discover the true system of nature. I will endeavour very soon to
give an answer to the remaining part of your excellent letter.
I have now just room to give you an account of the experiments I
have lately been engaged in, though they are not much connected
with light and heat.
_First._--One of Mr. William Coate's children accidentally
discovered that two bonnet-canes rubbed together produced a faint
light. The novelty of this phenomenon induced me to examine it, and
I found that the canes on collision produced sparks of light, as
brilliant as those from the flint and steel.
_Secondly._--On examining the epidermis, I found, when it was taken
off, that the canes no longer gave light on collision.
_Thirdly._--The epidermis, subjected to chemical analysis, had all
the properties of silex.
_Fourthly._--The similar appearance of the epidermis of reeds,
corn, and grasses, induced me to suppose that they likewise
contained silex. By burning them carefully, and analysing their
ashes, I found that they contained it in rather larger proportions
than the canes.
_Fifthly._--The corn and grasses contain sufficient potash to form
glass with their flint. A very pretty experiment may be made on
these plants with the blow-pipe. If you take a straw of wheat,
barley, or hay,[25] and burn it, beginning at the top, and heating
the ashes with the blue flame, you will obtain a perfect globule of
hard glass fit for microscopic experiments.
I made a discovery yesterday which proves how necessary it is
to repeat experiments. The gaseous oxide of azote is perfectly
respirable when pure. It is never deleterious but when it contains
nitrous gas. I have found a mode of obtaining it pure, and I
breathed to-day, in the presence of Dr. Beddoes and some others,
sixteen quarts of it for near seven minutes. It appears to support
life longer than even oxygen gas, and absolutely intoxicated me.
Pure oxygen gas produced no alteration in my pulse, nor any other
material effect; whereas this gas raised my pulse upwards of twenty
strokes, made me dance about the laboratory as a madman, and has
kept my spirits in a glow ever since. Is not this a proof of the
truth of my theory of respiration? for this gas contains more light
in proportion to its oxygen than any other, and I hope will prove a
most valuable medicine.
We have upwards of eighty out-patients in the Pneumatic
Institution, and are going on wonderfully well.
I shall hope for the favour of a letter from you, and in my answer
to it will fully inform you of our proceedings. I have just room to
add that I am
Yours, with affection and respect,
HUMPHRY DAVY.
[25] It is very common, after the burning of a hay-stack, to find
glass in the ashes. P.
I cannot suffer the experiments with the bonnet-canes to pass,
without endeavouring to infuse into the reader a portion of that
admiration which I feel in relating them. They furnish a beautiful
illustration of that combination of observation, experiment, and
analogy, first recommended by Lord Bacon, and so strictly adopted
by Davy in all his future grand researches.
In alluding to this discovery--that siliceous earth exists
generally in the epidermis of hollow plants--Davy observes in his
agricultural lectures, that "the siliceous epidermis serves as a
support, protects the bark from the action of insects, and seems
to perform a part in the economy of these feeble vegetable tribes,
similar to that performed in the animal kingdom by the shell of the
crustaceous insects."
The circumstance that first led him to the investigation of the
nature of _nitrous oxide_, or the _gaseous oxide of azote_, alluded
to in the foregoing letter, has been thus recorded by himself. "A
short time after I began the study of Chemistry, in March 1798, my
attention was directed to the _dephlogisticated nitrous gas_ of
Priestley (nitrous oxide) by Dr. Mitchell's theory of Contagion, by
which he attempted to prove that _dephlogisticated nitrous gas_!
which he calls _oxide of septon_, was the principle of contagion,
and capable of producing the most terrible effects, when respired
by animals in the minutest quantities, or even when applied to the
skin, or muscular fibre.
"The fallacy of this theory was soon demonstrated by a few coarse
experiments, made on small quantities of this gas procured, in the
first instance, from zinc and diluted nitrous acid. Wounds were
exposed to its action; the bodies of animals were immersed in it
without injury; and I breathed it, mingled in small quantities
with common air, without any remarkable effects. An inability to
procure it in sufficient quantities prevented me, at this time,
from pursuing the experiments to any greater extent. I communicated
an account of them to Dr. Beddoes."
His situation in the "Medical Pneumatic Institution" in 1799,
imposing upon him the duty of investigating the physiological
effects of such aëriform fluids as held out any promise of useful
agency, he resumed the investigation; a considerable period,
however, elapsed, before he succeeded in procuring _nitrous oxide_
in a state of purity; he was therefore obliged to breathe it in
mixture with oxygen gas, or common air; but as no just conclusion
could be deduced from the action of an impure gas, he commenced an
enquiry for the purpose of discovering a process by which it might
be procured in an uncontaminated condition; when, after a most
laborious investigation concerning its composition, properties,
and combinations, enquiries which were necessarily extended to the
different bodies connected with nitrous oxide, such as _nitrous
gas_, _nitrous acid_, and _ammonia_, he was enabled, by a series
of intermediate and comparative experiments, to reconcile apparent
anomalies, and thus, by removing the greater number of those
difficulties which had previously obscured this branch of science,
to present to the chemical world the first satisfactory history of
the COMBINATIONS OF OXYGEN AND NITROGEN.
Thus prepared, he proceeded to examine the action of nitrous oxide
upon living beings, and to compare it with the effects of other
gases upon man; and in this manner he completed its physiological,
as he had already done its chemical history.
These interesting results were published in a distinct volume, in
the year 1800, entitled, "Researches Chemical and Philosophical,
chiefly concerning Nitrous Oxide, and its Respiration. By Humphry
Davy, Superintendent of the Medical Institution."
It may be observed in passing, that the merits of this work could
never have been inferred from the title-page, which its most
sanguine admirers must admit to be as clumsy and unpromising an
invitation as an author ever addressed to his scientific brethren.
Amongst Davy's letters to Mr. Gilbert, I find one written on a
proof sheet of the chapter of contents of the above work, and which
may not be uninteresting in this place.
TO DAVIES GIDDY, ESQ.
July 3, 1800.
That our feelings, as well as our actions, are rendered stronger
and more vivid by habit, is probable from many facts, and from no
one more so than that of procrastination. My much respected friend,
two months after my return,[26] I had formed the resolution of
writing to you; week after week this resolution was renewed and put
off to a future day, with the hope that this day, by presenting
something new, would enable me to make my letter more interesting.
In vain! the feeling of procrastination, thus increased by
association, at length became so strong as to prevent me from
writing at all.[27]
I have received your letter; it has awakened my duties, and has
been doubly welcome, as being unexpected and undeserved.
Since my return to the Pneumatic Institution in December, I have
been almost incessantly occupied, from January to April, in
completing a series of experiments on Gases, and their application;
and from April to the present time, in writing and printing an
account of them.
I have written this letter on the table of contents of a work which
will be published in the course of the month, and of which I shall
take the earliest opportunity to send you a copy. This table of
contents will give you a better idea of the nature and extent of
the investigation, than I could possibly have given in a letter.
We have been repeating the Galvanic experiments with success.
Nicholson, by means of a hundred pieces of silver and zinc, has
procured a visible spark. Cruickshank has revived oxidated metals
in solution, by means of the nascent hydrogen produced from the
decomposition of water by the shock; and both he and Carlisle have
absolutely resolved water into oxygen and hydrogen by means of
it, making use of silver and platina wires. An immense field of
investigation seems opened by this discovery: may it be pursued so
as to acquaint us with some of the laws of life!
You have, undoubtedly, heard of Herschel's discovery concerning
the production of heat by invisible rays emitted from the sun. By
placing one thermometer within the red rays, separated by a prism,
and another beyond them, he found the temperature of the outside
thermometer raised more than that of the inside one.
When I first heard of Mr. Tennant's discovery,[28] I was very much
struck by an observation which you long ago made to me, on the
fertility of the Cornish lands, in which there was decomposed,
_feltspar_ or _serpentine_.
Mr. Tennant spent a day here some time ago, when I mentioned
your observation to him, but he could not give any solution of
the phenomenon. _Quere._--As lime and magnesia are probably both
subservient to vegetation, only from supplying plants with carbonic
acid, may not lime, when mingled with magnesia, in the process of
vegetation, render it partially caustic, and thus enable it to
destroy them?
Your observation on the scale of numbers, and the fact relative
to it, are highly interesting. Reasoning on this subject would
literally form the logic of generalization, or the application of
one term to signify many terms, or many ideas, on which science
ultimately depends. _Quere._--How far have the first attempts
at generalization arisen from accident, and how far from the
resemblance between ideas?
Dr. Beddoes has always ridiculed the "_Tractors_," in common with
all other reasonable men. He is about to publish a new work on the
Nitrous Acid.
J. Wedgwood is returned, very little altered for the better.
Coleridge is gone to reside in Cumberland; he was here the week
before last, and spent much time with me, and often spoke of you
with the greatest interest. Clayfield is at this moment chiefly
engaged in commercial speculations. He has found a new mode of
making soda, which there is every reason to believe will turn out
profitable.
I hope some time in the autumn to see you, and to enjoy the well
remembered pleasure of your conversation; in the mean while, I
remain, with respects to your family,
Yours with sincere affection,
HUMPHRY DAVY.
[26] From his visit to London, as noticed at page 62.
[27] With respect to the metaphysical speculation contained in
this paragraph of his letter, had he not written it in haste, we
might presume he would have given a more exact expression to his
ideas. By the misapplied term "_Feeling of Procrastination_," he
doubtless meant to describe that aversion to labour which becomes
habit by indulgence, and the perception of which, so far from
increasing in vividness, actually languishes to obtuseness. To
borrow an expression from Dr. Johnson, Davy, in his metaphysical
speculations, not unfrequently trod upon the brink of meaning,
where light and darkness begin to mingle.
[28] Davy here alludes to the fact of magnesian earth being
prejudicial to vegetation.
In estimating the early genius of Davy, and his character as a
philosopher, the style and matter of his "RESEARCHES" will afford
us much assistance. The close philosophical reasoning,--the
patient and penetrating industry,--the candid submission to every
intimation of experiment, and the accuracy of manipulation, so
remarkably displayed throughout this work, have been rarely
equalled, and perhaps never surpassed.
There is scarcely to be found a more striking illustration
of chemical genius, than that afforded by his chapter on the
"Absorption of _Nitrous Gas by solutions of green Sulphate of
Iron_."
The address with which he gradually disentangles the subject of
its difficulties, and catches at every opening to truth, affords
a study which may be safely recommended to the attention of every
young experimentalist, as being no less instructive than it is
beautiful.
The phenomena attending the absorption of _nitrous gas_ by
solutions of _sulphate of iron_ had been examined by Vauquelin and
by Berthollet, but the conclusions of these chemical philosophers
were fatally infected by errors, arising from the neglected action
of the atmosphere. Davy, by conducting his experiments over
mercury, proved that, in the absence of air, the absorption was
simply owing to a combination between the gas and the fluid; but
that, on admitting air, the nitrous _gas_ became nitrous _acid_, a
portion of which, together with a part of the water, subsequently
underwent decomposition, and gave origin to _ammonia_, and
ultimately to _nitrate of ammonia_, while the iron passed into the
state of a _peroxide_.
We have also to admire in this work an ardour for investigation,
which even the most imminent personal danger could not repress. He
may truly be said to have sought the bubble reputation in the very
jaws of Death. What shall we say of that spirit which led him to
inspire nitrous gas, at the hazard of filling his lungs with the
vapour of _aqua fortis_! or what, of that intrepid coolness which
enabled him to breathe a deadly gas, and to watch the advances of
its chilling power in the ebbing pulsations at the wrist!
These experiments, however, are far too interesting and important
to be related in any other than the author's own words; but it is
first necessary that his trials with the _nitrous oxide_ should be
considered.
He found that this gas might be most conveniently, as well as most
economically, prepared by the decomposition of a salt known by the
name of _nitrate of ammonia_, by the application of a regulated
heat; but, as the researches by which he arrived at this conclusion
are recorded at length in his work, and as the most important of
them are now embodied in every elementary system of chemistry, it
would not only be tedious but useless, to enter into a detail of
them upon this occasion.
"In April," he says, "I obtained nitrous oxide in a state
of purity, and ascertained many of its chemical properties.
Reflections upon these properties, and upon former trials, made me
resolve to inspire it in its pure form, for I saw no other way in
which its respirability, or powers, could be determined.
"I was aware of the danger of the experiment. It certainly would
never have been made, if the hypothesis of Dr. Mitchell had in
the least influenced my mind. I thought that the effects might,
possibly, be depressing and painful; but there were many reasons
which induced me to believe, that a single inspiration of a gas,
apparently possessing no immediate action on the irritable fibre,
could neither destroy, nor materially injure, the powers of life.
"On April 11th, I made the first inspiration of pure nitrous oxide.
It passed through the bronchiæ without stimulating the glottis, and
produced no uneasy sensations in the lungs.
"The result of this experiment proved that the gas was respirable,
and induced me to believe that a farther trial of its effects might
be made without danger.
"On April 16th, Dr. Kinglake being accidentally present, I breathed
three quarts of nitrous oxide from and into a silk bag, for
more than half a minute, without previously closing my nose, or
exhausting my lungs. The first inspirations occasioned a slight
degree of giddiness, which was succeeded by an uncommon sense of
fulness in the head, accompanied with loss of distinct sensation
and voluntary power,--a feeling analogous to that produced in
the first stage of intoxication; but unattended by pleasurable
sensation. Dr. Kinglake, who felt my pulse, informed me that it was
rendered quicker and fuller.
"This trial did not satisfy me with regard to its powers: comparing
it with the former ones, I was unable to determine whether the
operation was stimulant or depressing.
"I communicated the result to Dr. Beddoes, and on April the 17th,
he was present when the following experiment was made.
"Having previously closed my nostrils, and exhausted my lungs, I
breathed four quarts of the gas from and into a silk bag. The first
feelings were similar to those produced in the last experiment;
but in less than half a minute, the respiration being continued,
they diminished gradually, and were succeeded by a sensation
analogous to gentle pressure on all the muscles, attended by an
highly pleasurable thrilling, particularly in the chest and in the
extremities. The objects around me became dazzling, and my hearing
more acute. Towards the last inspirations, the thrilling increased,
the sense of muscular power became greater, and, at last, an
irresistible propensity to action was indulged in: I recollect but
indistinctly what followed; I know that my motions were various and
violent.
"These effects very soon ceased after the respiration of the
gas. In ten minutes I had recovered my natural state of mind.
The thrilling in the extremities continued longer than the other
sensations.
"This experiment was made in the morning; no languor or exhaustion
was consequent; my feelings throughout the day were as usual, and I
passed the night in undisturbed repose.
"The next morning the recollection of the effects of the gas was
very indistinct; and had not remarks written immediately after the
experiment recalled them to my mind, I should even have questioned
their reality."
Our philosopher very naturally doubted whether some of these strong
emotions might not, after all, be attributed to the enthusiasm
necessarily connected with the perception of agreeable feelings,
when he was prepared to expect painful sensations; but he says,
that subsequent experiments convinced him that the effects were
solely owing to the specific operation of the gas. He found that
he could breathe nine quarts of nitrous oxide for three minutes,
and twelve quarts for rather more than four; but that he could
never breathe it, in any quantity, so long as five minutes.
Whenever its operation was carried to the highest extent, the
pleasurable thrilling, at its height about the middle of the
experiment, gradually diminished, the sense of pressure on the
muscles was lost, impressions ceased to be perceived, vivid ideas
passed rapidly through the mind, and voluntary power was altogether
destroyed, so that the mouthpiece generally dropped from his
unclosed lips. When he breathed from six to seven quarts, muscular
motions were produced to a great extent: sometimes he manifested
his pleasure by stamping, or laughing only; at other times, by
dancing round the room, and vociferating.
During the progress of these experiments, it occurred to him that,
supposing _nitrous oxide_ to be analogous in its operation to
common stimulants, the debility occasioned by intoxication from
fermented liquors ought to be increased after excitement from this
gas, in the same manner as the debility produced by two bottles of
wine is increased by a third. To ascertain whether this was the
case, he drank a bottle of wine, in large draughts, in less than
eight minutes. His usual drink, he tells us, was water; he had
been little accustomed to take spirits or wine, and had never been
intoxicated but once before in the course of his life. Under such
circumstances, we may readily account for the powerful effects
produced by this quantity of wine, and which he describes in the
following manner:--
"Whilst I was drinking, I perceived a sense of fulness in the
head, and throbbing of the arteries, not unlike that produced in
the first stage of nitrous oxide excitement: after I had finished
the bottle, this fulness increased, the objects around me became
dazzling, the power of distinct articulation was lost, and I was
unable to stand steadily. At this moment, the sensations were
rather pleasurable than otherwise; the sense of fulness in the
head, however, soon increased, so as to become painful, and in
less than an hour I sunk into a state of insensibility. In this
situation I must have remained for two hours, or two hours and a
half. I was awakened by head-ache and painful nausea. My bodily and
mental debility were excessive, and the pulse feeble and quick.
"In this state, I breathed for near a minute and a half five quarts
of gas, which was brought to me by the operator for nitrous oxide;
but as it produced no sensations whatever, and apparently rather
increased my debility, I am almost convinced that it was, from some
accident, either common air, or very impure nitrous oxide.
"Immediately after this trial, I respired twelve quarts of oxygen
for nearly four minutes. It produced no alteration in my sensations
at the time, but immediately afterwards I imagined that I was a
little exhilarated.
"The head-ache and debility still, however, continuing with
violence, I examined some nitrous oxide which had been prepared
in the morning, and finding it very pure, I respired seven quarts
of it for two minutes and a half. I was unconscious of head-ache
after the third inspiration; the usual pleasurable thrilling
was produced, voluntary power was destroyed, and vivid ideas
rapidly passed through my mind; I made strides across the room,
and continued for some minutes much exhilarated; but languor and
depression, not very different in degree from those existing
before the experiment, succeeded; they however gradually went off
before bed-time.
"This experiment proved, that debility from intoxication was not
increased by excitement from nitrous oxide. The head-ache and
depression would probably have continued longer, had it not been
administered."
The same work contains an account of many other trials; but
sufficient has been extracted to show the zeal and intrepidity
with which he conducted his researches. To withhold, however, the
testimony which several other scientific persons have given, with
respect to the intoxicating influence of this gas, would be to
deprive the reader of some very amusing descriptions.
First appears Mr. W. Tobin, who tells us that he soon found his
nervous system agitated by the highest sensations of pleasure,
but which were difficult of description. When the bags were
exhausted and taken from him, he suddenly started from his chair,
and vociferating with pleasure, made towards those that were
present, as he wished they should participate in his feelings. He
struck gently at Davy, and a stranger entering the room at the
same moment, he made towards him, and gave him several blows,
but he adds, it was more in the spirit of good-humour, than in
that of anger. He then ran through different rooms in the house,
and at last returned to the laboratory, somewhat more composed,
although his spirits continued much elevated for some hours after
the experiment; he felt, however, no consequent depression,
either in the evening or day following. Upon another occasion,
he states that his sensations were superior to any thing he ever
before experienced; his step was firm, and all his muscular
power increased. His nerves were more alive to every surrounding
impression; he threw himself into several theatrical attitudes,
and traversed the laboratory with a quick step, while his mind was
elevated to a most sublime height: he says that "it is giving but
a faint idea of his feelings to say, that they resembled those
produced by a representation of an heroic scene on the stage, or by
reading a sublime passage in poetry, when circumstances contribute
to awaken the finest sympathies of the soul." The influence,
however, of this inspiring agent appears to have been as transitory
as its effects were vivid; for he afterwards observes, "I have
seldom lately experienced vivid sensations. The pleasure produced
by the gas is slight and tranquil, and I rarely feel sublime
emotions, or increased muscular power."
The first time that Mr. Clayfield breathed the gas, it produced
feelings analogous to those of intoxication. He was for some time
unconscious of existence, but at no period of the experiment
were his sensations agreeable; a momentary nausea followed, but
unconnected with languor or head-ache.
In a subsequent trial, it would appear that he did experience
certain thrillings which were highly pleasurable.
The account given by Dr. Kinglake agrees pretty much with those
already cited. He adds, however, that the inspiration of the gas
had the further effect of reviving rheumatic irritations in the
shoulder and knee-joints, which had not been previously felt for
many months.
Next appears Mr. Southey, the Laureate. The reader will no doubt be
prepared to hear that the nitrous oxide transported him, at least,
to the summit of Parnassus;--by no means: he laughed when the bag
was removed from his mouth, but it may be fairly questioned whether
this might not have been an expression of joy at the terrors he
had escaped; for he freely confesses that he could not distinguish
between the first feelings it occasioned, and an apprehension of
which he was unable to divest himself.
The first time Mr. Coleridge inspired the nitrous oxide, he felt
a highly pleasurable sensation of warmth over his whole frame: he
adds, that the only motion which he felt inclined to make, was
that of laughing at those who were looking at him: a symptom as
equivocal, perhaps, as that exhibited by the Laureate.
A number of other accounts are given, but those already related are
perhaps sufficient to establish the fact, that the gas in question
possesses an intoxicating quality, to which the enthusiasm of
persons submitting to its operation has imparted a character of
extravagance wholly inconsistent with truth.
It will be admitted that there must have been something singularly
ludicrous in the whole exhibition. Imagine a party of grave
philosophers, with bags of silk tied to their mouths, stamping,
roaring, and laughing about the apartment; it is scarcely possible
to conceive a richer subject for the pencil of a Bunbury. We cannot
then be surprised at any terms of ridicule in which a stranger,
witnessing such an operation, might describe it. M. T. Fievée[29]
appears to have considered the practice as a national vice, and
whimsically introduces it amongst the catalogue of follies to which
he considers the English nation to be addicted.
[29] Lettres sur l'Angleterre, 1802.
Taking leave of these laughing philosophers, we must now proceed to
a much more serious branch of the subject of Pneumatic Medicine.
"Having observed," says Davy, "that no painful effects were
produced by the application of nitrous gas to the bare muscular
fibre, I began to imagine that this gas might also be breathed with
impunity, provided it were possible in any way to free the lungs of
common air before inspiration, so as to prevent the formation of
nitrous acid.
"On this supposition, during a fit of enthusiasm produced by the
respiration of nitrous oxide, I resolved to endeavour to breathe
nitrous gas: one hundred and fourteen cubic inches of it were
accordingly introduced into the large mercurial air-holder; two
small silk bags of the capacity of seven quarts were filled with
nitrous oxide.
"After a forced exhaustion of my lungs, my nose being accurately
closed, I made three inspirations and expirations of nitrous oxide
in one of the bags, in order to free my lungs, as much as possible,
from atmospheric oxygen; then, after a full expiration of the
nitrous oxide, I transferred my lips from the mouthpiece of the bag
to that of the air-holder, and, turning the stop-cock, attempted to
inspire the nitrous gas. In passing through my mouth and fauces,
it tasted astringent and highly disagreeable; it occasioned a sense
of burning in the throat, and produced a spasm of the epiglottis,
so painful as to oblige me to desist immediately from attempts to
inspire it. After removing my lips from the mouthpiece, when I
opened them to inspire common air, _nitrous acid_ was immediately
formed in my mouth, which burnt the tongue and palate, injured the
teeth, and produced an inflammation of the mucous membrane, which
lasted for some hours.
"As, after the respiration of nitrous oxide, a small portion of the
residual atmospheric air always remained in the lungs mingled with
the gas, so is it probable that, in the experiment just related, a
minute portion of nitrous acid was formed; and, if so, I perhaps
owe the preservation of my life to the circumstance; for, supposing
that I had succeeded in taking a full inspiration of nitrous
gas, and even that it had not produced any positive effects, it
is not likely that I should, by breathing nitrous oxide, have
so completely freed my lungs from it, as to have prevented the
formation of nitrous acid, when I again inspired common air. I
never design again to attempt so rash an experiment."
His attempt to breathe carburetted hydrogen gas was scarcely less
terrific and appalling.
"Mr. Watt's observations on the respiration of diluted
_hydro-carbonate_ by man, and the experiments of Dr. Beddoes on the
destruction of animals by the same gas, proved that its effects
were highly deleterious.
"As it destroyed life, apparently by rendering the muscular fibre
inirritable, without producing any previous excitement, I was
anxious to compare its sensible effects with those of nitrous
oxide, which at this time I believed to destroy life by producing
the highest possible excitement.
"In the first experiment, I breathed for nearly a minute three
quarts of _hydro-carbonate_, mingled with nearly two quarts of
atmospheric air.[30] It produced a slight giddiness, pain in
the head, and a momentary loss of voluntary power; my pulse was
rendered much quicker and more feeble. These effects, however, went
off in five minutes, and I had no return of giddiness.
[30] "I believe it had never been breathed before by any
individual in a state so little diluted."
"Emboldened by this trial, I introduced into a silk bag four
quarts of gas nearly pure, which was carefully produced from the
decomposition of water by charcoal an hour before, and which had a
very strong and disagreeable smell.
"My friend Mr. James Tobin, junior, being present, after a forced
exhaustion of my lungs, the nose being accurately closed, I made
three inspirations and expirations of the hydro-carbonate. The
first inspiration produced a sort of numbness and loss of feeling
in the chest, and about the pectoral muscles. After the second, I
lost all power of perceiving external things, and had no distinct
sensation, except that of a terrible oppression on the chest.
During the third expiration, this feeling subsided, I seemed
sinking into annihilation, and had just power enough to cast off
the mouthpiece from my unclosed lips.
"A short interval must have passed, during which I respired
common air, before the objects around me were distinguishable.
On recollecting myself, I faintly articulated, '_I do not think
I shall die._' Placing my finger on the wrist, I found my pulse
thread-like, and beating with excessive quickness. In less than a
minute, I was able to walk, and the painful oppression on the chest
directed me to the open air.
"After making a few steps, which carried me to the garden, my
head became giddy, my knees trembled, and I had just sufficient
voluntary power to throw myself on the grass. Here the painful
feelings of the chest increased with such violence as to threaten
suffocation. At this moment I asked for some nitrous oxide. Mr.
Dwyer brought me a mixture of that gas with oxygen, and I breathed
it for a minute, and believed myself recovered.
"In five minutes the painful feelings began gradually to diminish;
in an hour they had nearly disappeared, and I felt only excessive
weakness, and a slight swimming of the head. My voice was very
feeble and indistinct.
"I afterwards walked slowly for half an hour with Mr. Tobin, and on
my return was so much stronger and better as to believe that the
effects of the gas had entirely passed off; though my pulse was
120, and very feeble. I continued without pain for nearly three
quarters of an hour, when the giddiness returned with such violence
as to oblige me to lie on the bed; it was accompanied with nausea,
loss of memory, and deficient sensation.
"In about an hour and a half, the giddiness went off, and was
succeeded by an excruciating pain in the forehead, and between the
eyes, with transient pains in the chest and extremities.
"Towards night these affections gradually diminished; and at ten no
disagreeable feeling, except weakness, remained. I slept sound, and
awoke in the morning very feeble and very hungry. No recurrence of
the symptoms took place, and I had nearly recovered my strength by
the evening.
"I have been minute in the account of this experiment, because
it proves, that _hydro-carbonate_ acts as a sedative; that is,
it produces diminution of vital action, and consequent debility,
without previously exciting. There is every reason to believe that,
had I taken four or five inspirations, instead of three, they would
have destroyed life immediately, without producing any painful
sensation."
The scientific and medical world are alike indebted to Davy for
this daring experiment; and, if the precautions it suggests be
properly attended to, it may become the means of preserving
human life. The experiment is also valuable as affording support
to physiological views, with which its author was probably not
acquainted.
In the first place, it may be necessary to apprize some of my
readers, that the "_hydro-carbonate_" here spoken of, differs
very little from the gas now so generally used to illuminate our
streets and houses. We have just seen how deadly are its qualities,
and that even in a state of extreme dilution it will affect our
sensations. The question then necessarily suggests itself, how
far this gas can be safely introduced into the interior of our
apartments? Did we not possess any direct evidence upon the
subject, the answer would be sufficiently obvious, since it is
impossible so to conduct its combustion, that a portion shall not
escape unburnt. Such is the theory; but what is our experience
upon the subject?--that pains in the head, nausea, and distressing
languor, have been repeatedly experienced in our theatres and
saloons, by persons inhaling the unburnt gas; that the atmosphere
of a room, although spacious and empty, will, if lighted with gas,
convey a sense of oppression to our organs of respiration, as if
we were inhaling an air contaminated with the breath of a hundred
persons.
In the next place, Davy's experiment is important, inasmuch as it
proves that, in cases of asphyxia, or suspended animation, there
exists a period of danger after the respiration has been restored,
and the circulation re-established, at which death may take place,
when we are the least prepared to expect it.
Bichat has shown that, when dark-coloured blood is injected into
the vessels of the brain by means of a syringe connected with the
carotid artery, the functions of the brain become immediately
disturbed, and in a short time entirely cease: the effect is
precisely similar, whether the dark-coloured blood be transmitted
to the brain by the syringe of the experimentalist, or by the heart
itself. Thus in cases of asphyxia, the dark-coloured blood which
has been propelled through the vessels during the suspension or
imperfect performance of respiration, acts like a narcotic poison
upon the brain; and no sooner, therefore, does it extend its malign
influence to that organ, than deleterious effects are produced,
and the animal, after apparent recovery, falls into a state of
stupor, the pupils of the eyes become dilated, the respiration
laborious, the muscles of the body convulsed, and it speedily dies,
_poisoned by its own blood_.
We are much indebted to Mr. Brodie for a series of experiments in
confirmation of these views; and a very interesting case occurred
some time since, in the neighbourhood of Windsor, which is well
calculated for their illustration. A corporal in the Guards, whose
name, if I am not mistaken, was Schofield, was seized with cramp
as he was bathing in the Thames, and remained for several minutes
under water. By judicious assistance, however, he was recovered,
and appeared to those about him to be free from any danger, when he
was attacked by convulsions and expired. Had the respiration been
artificially supported at this period, so as to have maintained the
action of the heart until the black blood had returned from the
brain, the life of the soldier might possibly have been saved.
In the experiment which has given origin to these reflections, Davy
distinctly states, that after having recovered from the _primary_
effects of the carburetted hydrogen gas, and taken a walk with
his friend Mr. Tobin, he was again seized with violent giddiness,
attended with nausea and loss of sensation. The imperfectly
oxygenized or dark-coloured blood had evidently affected the brain,
and his life, at this period, was probably in greater jeopardy than
in any other stage of the experiment.
Nothing daunted by the dangers to which the preceding experiments
had exposed him, Davy did not allow more than a week to elapse
before he attempted to respire _fixed air_, or _carbonic acid gas_;
but it was in vain that he made voluntary efforts to draw it into
the windpipe; for, the moment the epiglottis was raised a little,
such a painful irritation was induced as instantly to close it
spasmodically on the glottis; and thus, in repeated trials, was he
prevented from taking a single particle of carbonic acid into the
lungs. When, however, the gas was diluted with a little more than
double its volume of common air, he was enabled to breathe it for
nearly a minute, when it produced a slight degree of giddiness, and
an inclination to sleep.[31]
[31] It would thus appear that carbonic acid, in its most
concentrated form, may kill by exciting a spasmodic action,
in which the epiglottis is closed, and the entrance of air
into the lungs altogether prevented. In a diluted form, it may
destroy by its specific influence upon the blood, which would
seem to be of a highly sedative character. Death produced by
such an agent is probably attended with little or no suffering.
The younger Berthollet destroyed his life by inclosing himself
in an atmosphere of this description; and on commencing his
fatal experiment, he registered all the successive feelings he
experienced, which were such as would have been occasioned by a
narcotic:--a pause, and then an almost illegible word occurred:
it is presumed that the pen dropped from his hand,--and he was no
more.
It may perhaps appear extraordinary to the reader of the
"RESEARCHES," that although they were published not more than
eighteen months after the appearance of his "Essays on Heat and
Light," no allusion is made in them either to his theory or to his
new nomenclature. In relating his experiments upon Respiration,
he employs the conventional language of the schools, and the
word "_phos-oxygen_" does not once occur in the volume. This is
fully explained in a communication made by him to Mr. Nicholson,
and which was printed in his Journal a short time after the
publication of his Essays in the West Country Contributions; in
which he says,--"As facts have occurred to me with regard to
the decomposition of bodies, which I had supposed to contain
light, without any luminous appearance, I beg to be considered
as a _sceptic_ with respect _to my own_ particular theory of
the combinations of light, until I shall have satisfactorily
explained those anomalies by fresh experiments. On account of this
scepticism, and for other reasons, I shall in future use the common
nomenclature; excepting that, as my discoveries concerning the
gaseous oxide would render it highly improper to call a principle,
which in one of its combinations is capable of being absorbed by
venous blood, and of increasing the powers of life, _azote_,--I
shall name it, with Dr. Pearson, Chaptal, and others, NITROGENE;
and the _gaseous oxide of azote_ I shall call NITROUS OXIDE."
The same feeling is expressed at the conclusion of his Third
Research.--"It would be easy to form theories referring the
action of blood impregnated with _nitrous oxide_, to its power of
supplying the nervous and muscular fibre with such proportions of
condensed nitrogen, oxygen, light, or ethereal fluid, as enabled
them more rapidly to pass through those changes which constitute
their life; but we are unacquainted with the composition of dead
organized matter; and new instruments of experiment, and new
modes of research, must be found, before we can ascertain even our
capabilities of discovering the laws of life."
There is one circumstance connected with the views entertained
in this work which must not be passed over without notice. In
several passages he advocates the theory of the atmosphere being
a _chemical compound_ of oxygen and nitrogen; whereas, in later
years, he was amongst the first to insist upon its being simply a
mechanical mixture of these gases.
In consequence of the highly deleterious experiments which have
been already described, and of the constant labours of the
laboratory, and the repeated inhalation of acid and other vapours,
his health began visibly to decline, and he retired into Cornwall,
where he informs us that "the associations of ideas and feelings,
common exercise, a pure atmosphere, luxurious diet, and a moderate
indulgence in wine, in the course of a month, restored him to
health and vigour."
I find an allusion to this visit in a letter from his sister. "He
had," she says, "written to his mother of his intention to visit
her, but before the post had quitted Bristol, he was already on
his way to Penzance, and would have reached it before his letter,
had not his aunt, on whom he called in the neighbouring town of
Marazion, struck with his appearance of ill health, insisted on his
remaining there till the next day, lest his mother should be doubly
alarmed at his unexpected visit and altered looks." Miss Davy adds,
"This one fact will serve, at the same time, to illustrate his
attachment to home, and the impetuosity of his mind, which never
rested till the object he proposed was accomplished."
The following letter is inserted in this place, for the purpose
of fixing the period at which he first ascertained those new
facts in Voltaic electricity, which formed the basis of a future
communication to the Royal Society, and which may be said to
have paved the way to his grand discoveries in that branch of
science;--the dawning of that glorious day, which we shall
presently view in all its splendour and glory.
There is, moreover, something extremely interesting in receiving
from himself a simple and unadorned statement of results, as they
successively presented themselves to his observation--"Truths
plucked as they are growing, and delivered to you before their dew
is brushed off."
TO DAVIES GIDDY, ESQ.
Pneumatic Institution, October 20, 1800.
Be assured, my respected friend, that your last letter, though
short, was highly gratifying to me. At the moment it was brought
to me, I was about to depart with King and Danvers on an excursion
to the banks of the Wye. Our design was to see Tintern Abbey by
moonlight, and it was perfectly accomplished.
After viewing for three hours all the varieties of light and
shade which a bright full moon and a blue sky could exhibit in
this beautiful ruin, and after wandering for three days among
the many-coloured woods and rocks surrounding the river between
Monmouth and Chepstow, we arrived on the fourth day at Bristol,
having to balance against the pleasure of the tour, the fatigue of
a stormy voyage down the Wye, across the mouth of the Severn, and
up the Avon.
On analysing, after our return, specimens of the air collected from
Monmouth, from the woods on the banks of the Wye, and from the
mouth of the Severn, there was no perceptible difference; they were
all of similar composition to the air in the middle of Bristol;
that is, they contained about twenty-two per cent. of oxygen.
The air from the bladders of some sea-weed, apparently just cast
on shore, at the Old Passage, likewise gave the same results; so
that, comparing these experiments with those made by Cavendish,
Berthollet, &c. and by myself on other occasions, at different
temperatures, in different weather, and with different winds, I
am almost convinced that the whole of the lower stratum of the
atmosphere is of uniform composition.
No test can be more fallacious and imperfect than nitrous gas, on
account of the different composition of nitrous acid, formed in the
different manipulations of eudiometrical experiments.
The eudiometer that I have lately employed gives, in a few minutes,
the proportions of oxygen without correction.
In pursuing experiments on galvanism, during the last two months,
I have met with unexpected and unhoped-for success. Some of the
new facts on this subject promise to afford instruments capable of
destroying the mysterious veil which Nature has thrown over the
operations and properties of ethereal fluids.
Galvanism I have found, by numerous experiments, to be a _process
purely chemical_, and to depend wholly on the oxidation of metallic
surfaces, having different degrees of electric conducting power.
Zinc is incapable of decomposing _pure_ water; and if the zinc
plates be kept moist with _pure_ water, the galvanic pile does not
act; but zinc is capable of oxidating itself when placed in contact
with water, holding in solution either oxygen, atmospheric air,
or nitrous or muriatic acid, &c.: and under such circumstances,
the galvanic phenomena are produced, and their intensity is in
proportion to the rapidity with which the zinc is oxidated.
The galvanic pile only acts for a few minutes, when introduced into
hydrogen, nitrogen, or hydro-carbonate; that is, only as long as
the water between its plates holds some oxygen in solution: immerse
it for a few moments in water containing air, and it acts again.
It acts very vividly in oxygen gas, and less so in the atmosphere.
When its plates are moistened by marine acid, its action is very
powerful, but infinitely more so when nitrous acid is employed.
Five plates with nitrous acid gave sparks equal to those of the
common pile. From twenty plates the shock was insupportable.
I had almost forgotten to mention, that charcoal is a good galvanic
exciter, and decomposes water, like the metals, in the pile; but
I must stop, without being able to expatiate on the connection
which is now obvious between galvanism and some of the phenomena
of organic motion. I never consider the subject without having
forcibly impressed upon my imagination your observations[32] on the
science of the ethereal fluids, and I cannot help flattering myself
that this age will see your predictions verified. I remain with
sincere respect and affection,
Yours,
HUMPHRY DAVY.
[32] On conversing with Mr. Gilbert on the above passage, I
understand that it is an allusion to his opinion, that the
discovery of Galvanic power would ultimately lead to a knowledge
of the nature of light and heat.
That a work, of the character of the "RESEARCHES," replete with
ingenious novelty, and rich in chemical discovery, proceeding
from the pen of so young a man, should have excited very general
admiration in the philosophic world, is a circumstance that cannot
surprise us; but in a majority of cases, precocious merit enjoys
only an ephemeral popularity; the sensations it excites are too
vivid to be permanent, and the individual sinks into an obscurity
rendered ten times more profound by the brilliancy of the flash
which preceded it; but every event of Davy's life would appear
as if created, and directed for his welfare, by some presiding
genius, whose activity, in throwing opportunities in his way was
rivalled only by the address with which he converted them to his
advantage. Fortune and talent, then, were both equally engaged
in accomplishing the elevation of Davy, and it is probable that
eminent success generally requires a combination of these elements
for its production, and that the maxim of Plautus is therefore as
remote from truth as that of Theophrastus, the one assigning all to
fortune, the other all to talent.
The experiments to which allusions have been frequently made
during the present chapter, favourably as they were received,
might have shared the fate of many other discoveries which did
not admit of an immediate and obvious application to the purposes
of common life; for statistical value is a necessary passport to
popular favour. Fortunately, however, for Davy, before the vivid
impression produced by his new work had lost the glow of novelty,
Count Rumford was anxiously seeking for some rising philosopher,
who might contribute his energies towards the support, and farther
increase, of the chemical fame of the recently established
"INSTITUTION OF GREAT BRITAIN."
It is not surprising that his attention should have been readily
directed to one whose genius had been so lately displayed, and
whose views regarding Caloric[33] were in such exact conformity
with his own opinions.
[33] Mr. Gilbert no sooner discovered the tendency of Davy's
opinions respecting the immateriality of Caloric, than he urged
him to communicate them to Count Rumford, but he considered
himself pledged to Dr. Beddoes, and his Essays were accordingly
printed in the West Country Contributions. Count Rumford, it may
be observed, maintained that Caloric, like _Phlogiston_, was
merely a creature of the chemist's imagination, and had no real
existence. He considered heat as nothing more than the motions
of the constituent particles of bodies amongst themselves,--an
hypothesis which has no claims to novelty, being perhaps one
of the most ancient on record.--See his paper on Heat, _Phil.
Trans._ for 1804.
As the philosophical public must feel a lively interest in every
incident connected with a transaction so important to the interests
of science, as that by which Davy was placed in the chemical chair
of the Institution, I am fortunate in being able, through the
kindness of his two friends, Mr. Thomson and Mr. Underwood, to
present a clear and satisfactory statement of all its circumstances
and details.