THE PNEUMATIC INSTITUTION, BRISTOL, 1798-1801.
On October 2nd, 1798, Davy set out for Clifton with such books and
apparatus as he possessed, and the MSS. of his essays on Heat and Light
safely stowed away among his baggage. He was in the highest spirits,
and full of confidence in the future. On his way through Okehampton he
met the London coach decked with laurels and ribbons, and bringing the
news of Nelson’s victory of the Nile, which he interpreted as a happy
omen. A few days after his arrival, he thus wrote to his mother:--
“_October 11th, 1798._ Clifton.
“MY DEAR MOTHER,--I have now a little leisure time, and I am
about to employ it in the pleasing occupation of communicating to
you an account of all the _new_ and _wonderful_ events that have
happened to me since my departure.
“I suppose you received my letter, written in a great hurry last
Sunday, informing you of my safe arrival and kind reception. I
must now give you a more particular account of Clifton, the place
of my residence, and of my new friends Dr. and Mrs. Beddoes and
their family.
“Clifton is situated on the top of a hill, commanding a view
of Bristol and its neighbourhood, conveniently elevated above
the dirt and noise of the city. Here are houses, rocks, woods,
town and country in one small spot; and beneath us, the
sweetly-flowing Avon, so celebrated by the poets. Indeed there
can hardly be a more beautiful spot; it almost rivals Penzance
and the beauties of Mount’s Bay.
“Our house is capacious and handsome; my rooms are very large,
nice and convenient; and, above all, I have an excellent
laboratory. Now for the inhabitants, and, first, Dr. Beddoes,
who, between you and me, is one of the most original men I ever
saw--uncommonly short and fat, with little elegance of manners,
and nothing characteristic _externally_ of genius or science;
extremely silent, and in a few words, a very bad companion. His
behaviour to me, however, has been particularly handsome. He has
paid me the highest compliments on my discoveries, and has, in
fact, become a convert to my theory, which I little expected. He
has given up to me the whole of the business of the Pneumatic
Hospital, and has sent to the editor of the _Monthly Magazine_ a
letter, to be published in November, in which I have the honour
to be mentioned in the highest terms. Mrs. Beddoes is the reverse
of Dr. Beddoes--extremely cheerful, gay and witty; she is one of
the most pleasing women I have ever met with. With a cultivated
understanding and an excellent heart, she combines an uncommon
simplicity of manners. We are already very great friends. She
has taken me to see all the fine scenery about Clifton; for the
Doctor, from his occupations and his bulk, is unable to walk
much. In the house are two sons and a daughter of Mr. Lambton,
very fine children, from five to thirteen years of age.
“I have visited Mr. Hare, one of the principal subscribers to
the Pneumatic Hospital, who treated me with great politeness.
I am now very much engaged in considering of the erection of
the Pneumatic Hospital, and the mode of conducting it. I shall
go down to Birmingham to see Mr. Watt and Mr. Keir in about a
fortnight, where I shall probably remain a week or ten days;
but before then you will again hear from me. We are just going
to print at Cottle’s; in Bristol, so that my time will be much
taken up the ensuing fortnight in preparations for the press. The
theatre for lecturing is not yet open; but, if I can get a large
room in Bristol, and subscribers, I intend to give a course of
chemical lectures, as Dr. Beddoes seems much to wish it.
“My journey up was uncommonly pleasant; I had the good fortune
to travel all the way with acquaintances. I came into Exeter in
a most joyful time, the celebration of Nelson’s victory. The
town was beautifully illuminated, and the inhabitants loyal and
happy....
“It will give you pleasure when I inform you that all my
expectations are answered and that my situation is just what I
could wish. But, for all this, I very often think of Penzance and
my friends, with a wish to be there; however that time will come.
We are some time before we become accustomed to new modes of
living and new acquaintances.
“Believe me, your affectionate son,
“HUMPHRY DAVY.”
Mrs. Beddoes, of whom Davy speaks in such appreciative terms, was one
of the many sisters of Maria Edgeworth. She seems to have possessed
much of the intelligence, wit, vivacity, and sunny humour of the
accomplished authoress of “Castle Rackrent”; and, by her charm of
manner and her many social gifts, to have made her husband’s house the
centre of the literary and intellectual life of Clifton. Thanks to her
influence, Davy had the good fortune to be brought into contact, at
the very outset of his career, with Southey, Coleridge, the Tobins,
Miss Edgeworth, and other notable literary men and women of his time,
with many of whom he established firm and enduring friendships. He had
always a sincere admiration for his fair patroness, and a grateful
memory of her many acts of kindness to him at this period of his life.
That she in turn had an esteem amounting to affection for the gifted
youth is evident from the language of tender feeling and warm regard in
which her letters to him are expressed. The sonnets accompanying these
letters are couched in terms which admit of no doubt of the strength of
her sentiments of sympathy and admiration, and some of the best efforts
of his muse were addressed to her in return.
His work and prospects at the Pneumatic Institution are sufficiently
indicated in the following letter to his friend and patron, Mr. Davies
Gilbert, written five weeks after his arrival at Clifton:--
“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 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 [chlorine] would
stand the highest, if we may judge from its effects on the
lungs; then, probably, _gaseous oxyd of azote_ [nitrous oxide?]
and _hydrocarbonate_ [the gases obtained by passing steam over
red-hot charcoal].
“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.[B]...
“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 ... is as good, amiable, and elegant as when you
saw her.
“Believe me, dear Sir, with affection and respect, truly yours,
“HUMPHRY DAVY.”
[B] _Cf._ An account of several veins of Sulphate of
Strontites, found in the neighbourhood of Bristol, with
an Analysis of the different varieties. By W. Clayfield.
“Nicholson’s Journ.,” III., 1800, pp. 36-41.
The work alluded to in this letter made its appearance in the early
part of 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 half of the volume, in accordance with the
editor’s promise, is occupied by two essays from Davy: the first “On
Heat, Light, and the Combinations of Light, with a new Theory of
Respiration”; the second “On the Generation of Phosoxygen (Oxygen Gas),
and on the Causes of the Colours of Organic Beings.”
To the student these essays have no other interest than is due to
the fact that they are Davy’s first contribution to the literature
of science. No beginning could be more inauspicious. It is the first
step that costs, and Davy’s first step had well nigh cost him all that
he lived for. As additions to knowledge they are worthless; indeed,
a stern critic might with justice characterise them in much stronger
language. Nowadays such writings would hopelessly damn the reputation
of any young aspirant for scientific fame, for it is indeed difficult
to believe, as we read paragraph after paragraph, that their author had
any real conception of science, or that he was capable of understanding
the need or appreciating the value of scientific evidence.
The essays are partly experimental, partly speculative, and the
author apparently would have us believe that the speculations are
entirely subservient to and dependent on the experiments. Precisely
the opposite is the case. Davy’s work had its origin in Lavoisier’s
“Traité Elémentaire,” almost the only text-book of chemistry he
possessed. Lavoisier taught, in conformity with the doctrine of
his time, that heat was a material substance, and that oxygen
was essentially a compound body, composed of a simple substance
associated with the matter of heat, or caloric. The young novitiate
puts on his metaphysical shield and buckler; and with the same jaunty
self-confidence that he assailed Locke and criticised Berkeley, enters
the lists against this doctrine, determined, as he told Gregory Watt,
“to demolish the French theory in half an hour.”
After a few high-sounding but somewhat disconnected introductory
sentences, and a complimentary allusion to “the theories of a
celebrated medical philosopher, Dr. Beddoes,” he proceeds to put
Lavoisier’s question, “La lumière, est-elle une modification du
calorique, ou bien le calorique est-il une modification de la lumière?”
to the test of experiment. This he does by repeating Hawksbee’s old
experiment of snapping a gunlock “armed with an excellent flint” in an
exhausted receiver. The experiment fails in his hands; such phenomena
as he observes he misinterprets, and he at once concludes that light
and heat have nothing essentially in common. “Nor can light be as some
philosophers suppose, a vibration of the imaginary fluid ether. For
even granting the existence of this fluid it must be present in the
exhausted receiver as well as in atmospheric air; and if light is a
vibration of this fluid, generated by collision between flint and steel
in atmospheric air, it should likewise be produced in the exhausted
receiver, where a greater quantity of ether is present, which is not
the case.” Since, then, it is neither an effect of caloric nor of an
ethereal fluid, and “as the impulse of a material body on the organ
of vision is essential to the generation of a sensation, _light is
consequently matter of a peculiar kind_, capable when moving through
space with the greatest velocity, of becoming the source of a numerous
class of our sensations.”
By experiments, faultless in principle but wholly imperfect in
execution, he next seeks to show that caloric, or the matter of heat,
has no existence. His reasoning is clear, and his conceptions have
the merit of ingenuity, but any real acquaintance with the conditions
under which the experiments were made would have convinced him that
the results were untrustworthy and equivocal; and yet, in spite of
the dubious character of his observations, he arrived at a theory
of the essential nature of heat which is in accord with our present
convictions, and which he states in the following terms:--
“Heat, or that power which prevents the actual contact of the
corpuscles of bodies, and which is the cause of our peculiar
sensations of heat and cold, may be defined a peculiar motion,
probably a vibration, of the corpuscles of bodies, tending to
separate them.”
This conception of the nature of heat did not, of course, originate
with him, and it was a question with his contemporaries how far he was
influenced by Rumford’s work and teaching. On this point Dr. Beddoes’s
testimony is direct and emphatic. He says:--
“The author [Davy] derived no assistance whatever from the
Count’s ingenious labours. My first knowledge of him arose from
a letter written in April 1798, containing an account of his
researches on heat and light; and his first knowledge of Count
Rumford’s paper was conveyed by my answer. The two Essays contain
proofs enough of an original mind to make it credible that
the simple and decisive experiments on heat were independently
conceived. Nor is it necessary, in excuse or in praise of his
system, to add, that, at the time it was formed, the author was
under twenty years of age, pupil to a surgeon-apothecary, in the
most remote town of Cornwall, with little access to philosophical
books, and none at all to philosophical men.”
Having thus, with Beddoes, expunged caloric from his chemical system,
Davy proceeds to elevate the matter of light into its place. According
to Lavoisier oxygen gas was a compound of a simple substance and
caloric; Davy seeks to show that it is a compound of a simple substance
and light. He objects to the use of the word “gas,” since, according to
French doctrine, it is to be taken as implying not merely a state of
aggregation but a combination of caloric with another substance, and
suggests therefore that what was called oxygen gas should henceforth be
known as _phosoxygen_. His “proofs” that oxygen is really a compound of
a simple substance with “matter in a peculiar state of existence” are
perhaps the most futile that could be imagined. Charcoal, phosphorus,
sulphur, hydrogen, and zinc were caused to burn in oxygen; _light_ was
evolved, oxides were formed, _and a deficiency of weight was in each
case observed_. He regrets, however, that he “possessed no balance
sufficiently accurate to determine exactly the deficiency of weight
from the light liberated in different combustive processes.”
“From these experiments, it appears that in the chemical process
of the formation of many oxyds and acids, light is liberated,
the phosoxygen and combustible base consumed, and a new body
formed.... Since light is liberated in these processes, it is
evident that it must be liberated either from the phosoxygen
or from the combustible body.... If the light liberated in
combustion be supposed (according to Macquer’s and Hutton’s
theories) to arise from the combustible body, then phosoxygen
must be considered as a simple substance; and it follows on this
supposition, that whenever phosoxygen combines with combustible
bodies, either directly or by attraction from any of its
combinations, light must be liberated, which is not the case, as
carbon, iron and many other substances, may be oxydated by the
decomposition of water without the liberation of light.”
Davy is here on the horns of a dilemma, but he ignores the difficulty,
and, with characteristic “flexibility of adaptation,” proceeds to offer
synthetical proofs “that the presence of light is absolutely essential
to the production of phosoxygen.” The character of the “proofs” is
sufficiently indicated by the following extracts:--
“When pure oxyd of lead is heated as much as possible, included
from light, it remains unaltered; but when exposed to the light
of a burning-glass, or even of a candle, phosoxygen is generated
and the metal revivified.”
“Oxygenated muriatic acid [chlorine] is a compound of muriatic
acid, oxygen and light, as will be hereafter proved. The combined
light is not sufficient to attract the oxygen from the base
[muriatic acid] to form phosoxygen; but its attraction for oxygen
renders the [oxygenated muriatic] acid decomposable. If this acid
be heated in a close vessel and light excluded no phosoxygen is
formed; but if it be exposed to the solar light, phosoxygen is
formed; the acid loses its oxygen and light and becomes muriatic
acid.”
“A plant of Arenaria Tenuifolia planted in a pot filled with
very dry earth, was inserted in carbonic acid, under mercury.
The apparatus was exposed to the solar light, for four days
successively, in the month of July. By this time the mercury had
ascended considerably. The gas in the vessel was now measured.
There was a deficiency of one-sixth of the whole quantity. After
the carbonic acid was taken up by potash, the remaining quantity,
equal to one-seventh of the whole, was _phosoxygen almost pure_.
From this experiment, it is evident that carbonic acid is
decomposed by two attractions; that of the vegetable for carbon
and of light for oxygen: the carbon combines with the plant,
and the light and oxygen combined are liberated in the form of
phosoxygen.”
The accounts which Davy gives of his experiments, as well as of the
phenomena which he professes to have observed, may awaken an uneasy
doubt as to his absolute integrity; for, it is hardly necessary to
point out, he could not possibly have obtained the results which he
describes. The presence or absence of light in no wise affects the
decomposition by heat of minium; chlorine, as he himself subsequently
established, contains no oxygen; and a plant is incapable of
decomposing pure undiluted carbonic acid, even in the brightest
sunshine. But the work of a youth of nineteen, imaginative, sanguine,
and impetuous, with no training as an experimentalist, and with only
a limited access to scientific memoirs, cannot be judged by too
severe a canon. The faculty of self-deception, even in the largest
and most receptive minds, often in those of matured power and ripened
experience, is boundless. Davy himself affords an exemplification of
the truth of his own words, written years afterwards: “The human mind
is always governed not by what it knows, but by what it believes; not
by what it is capable of attaining, but by what it desires.”
It is not necessary to show how the presumptuous youth drove his hobby
with all the reckless daring of a Phæton. Phlogiston and oxygen had in
turn been the central conceptions of theories of chemistry; phosoxygen
was to supplant them. It was to explain everything--the blue colour
of the sky, the electric fluid, the Aurora Borealis, the phenomena of
fiery meteors, the green of the leaf, the red of the rose, and the
sable hue of the Ethiopian; perception, thought, and happiness; and why
women are fairer than men. But Jupiter, in the shape of a Reviewer,
soon hurled the adventurous boy from the giddy heights to which he had
soared. The “West Country Collection” received scant sympathy from the
critics, and the phosoxygen theory was either mercilessly ridiculed, or
treated with contempt.
There is no doubt that Davy keenly felt the position in which he now
stood. His pride was humbled, and the humiliation was as gall and
wormwood. The vision of fame which his ardour had conjured up on the
top of the Bristol coach--was it all a baseless fabric, and its train
of honours and emoluments an insubstantial pageant? All he could plead
was that his critics had not understood that these experiments were
made when he had studied chemistry only four months, when he had never
seen a single experiment executed, and when all his information was
derived from Nicholson’s “Chemistry” and Lavoisier’s “Elements.” But
his good sense quickly came to his rescue. After the first feelings of
anger and mortification had passed, he recognised the justice of his
punishment, much as he might resent the mode in which it was inflicted.
How keen was the smart will appear from the following reflection,
written in the August of the year in which the essays were published:--
“When I consider the variety of theories that may be formed
on the slender foundation of one or two facts, I am convinced
that it is the business of the true philosopher to avoid them
altogether. It is more laborious to accumulate facts than to
reason concerning them; but one good experiment is of more value
than the ingenuity of a brain like Newton’s.”
About the same time he wrote:--
“I was perhaps wrong in publishing, with such haste, a new theory
of chemistry. My mind was ardent and enthusiastic. I believed
that I had discovered the truth. Since that time my knowledge of
facts is increased--since that time I have become more sceptical.”
In the October of the same year he wrote:--
“Convinced as I am that chemical science is in its infancy, that
an infinite variety of new facts must be accumulated before our
powers of reasoning will be sufficiently extensive, I renounce my
own particular theory as being a complete arrangement of facts:
it appears to me now only as the most _probable_ arrangement.”
By the end of the year the repentance was complete, and recantation
followed. In a letter which appeared in Nicholson’s Journal in
February, 1800, he corrects some of the errors into which he had
fallen, and says, “I beg to be considered as a sceptic with regard to
my own particular theory of the combinations of light, and theories of
light in general.” To the end of his days Davy never forgot the lesson
which his earliest effort had taught him; and there is no question that
the memory of it acted as a salutary check on the exuberance of his
fancy and the flight of his imagination. The wound to his self-love
was, however, never wholly healed. Nothing annoyed him more than any
reference to Beddoes’s book, and he declared to Dr. Hope that he would
joyfully relinquish any little glory or reputation he might have
acquired by his later researches were it possible to withdraw his share
in that work and to remove the impression he feared it was likely to
produce.
And yet, in spite of the unqualified censure with which they were
received, and of the severe condemnation of them by their own author,
we are disposed to agree with Dr. Davy that posterity will not suffer
these essays to be wholly blotted out from the records of science. That
the experimental part was for the most part radically bad, that the
generalisation was hasty and presumptuous, and the reasoning imperfect,
cannot be gainsaid. But, withal, the essays display some of Davy’s
best and happiest characteristics. There is dignity of treatment and a
sense of the nobility of the theme on which he is engaged; the literary
quality is admirable; there is clearness of perception and perspicuity
of statement; the facts as he knew them--or as he thought he knew
them--are marshalled with ingenuity and with a logical precision
worthy of his model and teacher Lavoisier; his style is sonorous and
copious, even to redundancy--some of the periods indeed glow with all
the fervour and richness of his Royal Institution lectures. However
wild and visionary his speculations may seem, minds like those of
Coleridge and Southey were not insensible to the intrinsic beauty of
some of his ideas. His theory of respiration might not be true, but
it had at least the merit of poetic charm in its consequence that the
power and perspicacity of a thinker had some relation to the amount of
light secreted by his brain. Even good old Dr. Priestley, whose Pegasus
could never be stirred beyond the gentlest of ambles, tells us in the
Appendix to his “Doctrine of Phlogiston Established” that Mr. H. Davy’s
essays had impressed him with a high opinion of the philosophical
acumen of their author. “His ideas were to me new and very striking;
but,” he adds, with a caution that was not habitual, “they are of too
great consequence to be decided upon hastily.”
Among the letters entrusted to me is one from Priestley, which must
have been particularly gratifying to the young man. It is as follows:--
“Northumberland, _Oct. 31, 1801_.
“SIR,--I have read with admiration your excellent publications,
and have received much instruction from them. It gives me
peculiar satisfaction that, as I am far advanced in life,
and cannot expect to do much more, I shall leave so able a
fellow-labourer of my own country in the great fields of
experimental philosophy. As old an experimenter as I am, I was
near forty before I made any experiments on the subject of
Air, and then without, in a manner, any previous knowledge of
chemistry. This I picked up as I could, and as I found occasion
for it, from books. I was also without apparatus, and laboured
under many other disadvantages. But my unexpected success induced
the friends of science to assist me, and then I wanted for
nothing. I rejoice that you are so young a man; and perceiving
the ardour with which you begin your career, I have no doubt of
your success.
“My son, for whom you express a friendship, and which he warmly
returns, encourages me to think that it may not be disagreeable
to you to give me information occasionally of what is passing in
the philosophical world, now that I am at so great a distance
from it, and interested, as you may suppose, in what passes in
it. Indeed, I shall take it as a great favour. But you must not
expect anything in return. I am here perfectly insulated, and
this country furnishes but few fellow-labourers, and these are so
scattered, that we can have but little communication with each
other, and they are equally in want of information with myself.
Unfortunately, too, correspondence with England is very slow and
uncertain, and with France we have not as yet any intercourse at
all, tho we hope to have it soon....
“I thank you for the favourable mention you so frequently make of
my experiments, and have only to remark that in Mr. Nicholson’s
Journal you say that the conducting power of charcoal was first
observed by those who made experiments on the pile of Volta;
whereas it was one of the earliest that I made, and gave an
account of in my History of Electricity, and in the Philosophical
Transactions. And in your treatise on the Nitrous Oxide p. 55
you say, and justly, that I concluded this air to be lighter
than that of the atmosphere. This, however, was an error in the
printing that I cannot account for. It should have been _alkaline
air_, as you will see the experiment necessarily requires.
“With the greatest esteem, I am Sir, yours sincerely
“J. PRIESTLEY.”
In Davy’s next contribution, “On the Silex composing the Epidermis, or
External Bark, and contained in other parts of certain Vegetables,”
published in Nicholson’s Journal in the early part of 1800, we find
the evidence of a chastened and contrite spirit. The theme is humble
enough, and the language as sober and sedate as that of Mr. Cavendish.
The chance observation of a child that two bonnet-canes rubbed together
in the dark produced a luminous appearance, led him to investigate the
cause, which he found to reside in the crystallised silica present
in the epidermis. Reeds and grasses, and the straw of cereals, were
also found to be rich in silica, from which he concludes that “the
flint entering into the composition of these hollow vegetables may
be considered as analogous to the bones of animals; it gives to them
stability and form, and by being situated in the epidermis more
effectively preserves their vessels from external injury.” It is
doubtful, however, whether the rigidity of the stems of cereals is
wholly due to the silica they contain.
From a letter to Mr. Davies Gilbert, dated April 10th, 1799, we
learn that he had now begun to investigate the effects of gases in
respiration. In the early part of the year he had removed to a house
in Dowry Square, Clifton, where he had fitted up a laboratory. After
thanking his friend for his critical remarks on his recently published
essays, he says:
“Your excellent and truly philosophic observations will induce
me to pay greater attention to all my positions.... 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.”
This observation of the respirability of nitrous oxide, and of the
effects of its inhalation, was quickly confirmed. Southey, Coleridge,
Tobin (the dramatist), Joseph Priestley, the son of the chemist, the
two Wedgwoods, and a dozen other people of lesser note were induced
to breathe the gas and to record their sensations. The discovery was
soon noised abroad; Dr. Beddoes dispatched a short note to Nicholson’s
Journal, and the fame of the Pneumatic Institution went up by leaps and
bounds.
Maria Edgeworth, who was at the time on a visit to her sister, thus
writes:--
“A young man, a Mr. Davy, at Dr. Beddoes’, who has applied
himself much to chemistry, has made some discoveries of
importance, and enthusiastically expects wonders will be
performed by the use of certain gases, which inebriate in the
most delightful manner, having the oblivious effects of Lethe,
and at the same time giving the rapturous sensations of the
Nectar of the Gods! Pleasure even to madness is the consequence
of this draught. But faith, great faith, is I believe necessary
to produce any effect upon the drinkers, and I have seen some of
the adventurous philosophers who sought in vain for satisfaction
in the bag of _Gaseous Oxyd_, and found nothing but a sick
stomach and a giddy head.”
Laughing-gas, indeed threatened to become, like Priestley’s
dephlogisticated air, “a fashionable article in luxury.” Monsieur
Fiévée, in his “Lettres sur l’Angleterre, 1802,” names it in the
catalogue of follies to which the English were addicted, and says the
practice of breathing it amounted to a national vice!
Davy had no sooner discovered that the gas might be respired, than he
proceeded to attack the whole subject of the chemistry of the oxides
of nitrogen, and of nitrous oxide in particular, and after ten months
of incessant labour he put together the results of his observations in
an octavo volume, entitled, “Researches, Chemical and Philosophical,
chiefly concerning Nitrous Oxide, or Dephlogisticated Nitrous Air,
and its Respiration. By Humphry Davy, Superintendent of the Medical
Institution.” The book appeared in the summer of 1800, and immediately
re-established its author’s character as an experimentalist. Thomson,
in his “History of Chemistry,” says of it: “This work gave him at once
a high reputation as a chemist, and was really a wonderful performance,
when the circumstances under which it was produced are taken into
consideration.” In spite, however, of the eulogies with which it was
welcomed, its sale was never very extensive, and a second edition was
not required. In fact, the work as a whole was hardly calculated to
attract the general public, whose only concern with laughing-gas was in
its powers as an exhilarant. Indeed, this aspect of the question is not
wholly lost on Davy himself, who is careful to point out that “if the
pleasurable effects or medical properties of the nitrous oxide should
ever make it an article of general request, it may be procured with
much less time, labour, and expense than most of the luxuries, or even
necessaries, of life”; and in a footnote he adds. “A pound of nitrate
of ammonia costs 5s. 10d. (its present price is 9d.!). This pound,
properly decomposed, produces rather more than 34 moderate doses of the
air, so that the expense of a dose is about 2d. What fluid stimulus
can be procured at so cheap a rate?”
To the chemical student the book had, and still has, many features of
interest. It contains a number of important facts, based on original
and fairly accurate observation. In the arrangement of these facts
“I have been guided as much as possible,” says their author, “by
obvious and simple analogies only. Hence, I have seldom entered into
theoretical discussions, particularly concerning light, heat, and other
agents, which are known only by isolated effects. Early experience
has taught me the folly of hasty generalisation.” The work is divided
into four main sections. The first chiefly relates to the production
of nitrous oxide, and the analysis of nitrous gas and nitrous acid.
He minutely studies the mode of decomposition of ammonium nitrate
(first observed by Berthollet), and shows that it is an endothermic
phenomenon, varying in character with the temperature and manner of
heating. He is thus led to offer the following _Speculations on the
Decompositions of Nitrate of Ammonia_:--
“All the phenomena of chemistry concur in proving that the
affinity of one body, A, for another, B, is not destroyed by
its combination with a third, C, but only modified; either by
condensation or expansion, or by the attraction of C for B.
On this principle the attraction of compound bodies for each
other must be resolved into the reciprocal attractions of their
constituents, and consequently the changes produced in them by
variations of temperature explained from the alterations produced
in the attractions of those constituents.”
The singular property possessed by ammonium nitrate of decomposing
in several distinct modes according to the rapidity of heating and
the temperature to which the substance is raised, first indicated by
Davy, has been minutely studied by M. Berthelot, who has shown that
this comparatively simple salt may be decomposed in as many as six
different ways. It may be (1) dissociated into gaseous nitric acid and
ammonia; (2) decomposed into nitrous oxide and water; (3) resolved into
nitrogen, oxygen, and water, (4) or into nitric oxide, nitrogen, and
water, (5) or into nitrogen, nitrogen peroxide, and water; or lastly
(6), under the influence of spongy platinum, it may be resolved into
gaseous nitric acid, nitrogen, and aqueous vapour. These different
modes of decomposition may be distinct or simultaneous; or, more
exactly, the predominance of any one of them depends on relative
rapidity and on the temperature at which decomposition is produced.
This temperature is not fixed, but is itself subordinate to the
rapidity of heating (_cf._ Berthelot’s “Explosives and Their Power,”
translated by Hake and Macnab). The assertion of De la Metherie, that
the gas produced by the solution of platinum in nitromuriatic acid was
identical with the dephlogisticated nitrous air of Priestley (nitrous
oxide), led Davy to examine the gaseous products of this reaction more
particularly. He had no difficulty in disproving the statement of the
French chemist; but his observations, although accurate, led him to
no definite conclusion. “It remains doubtful,” he says, “whether the
gas consists simply of highly oxigenated muriatic acid and nitrogen,
produced by the decomposition of nitric acid from the coalescing
affinities of platina and muriatic acid for oxygen; or whether it is
composed of a _peculiar_ gas, analogous to oxigenated muriatic acid and
nitrogen, generated from some unknown affinities.” The real nature of
the gas, which has also been considered by Lavoisier as a particular
species, not hitherto described, was first established by Gay Lussac,
when Davy had himself proved that “oxigenated muriatic acid” was a
simple substance.
In the second section the combinations and composition of nitrous
oxide are investigated, and an account is given of its decomposition
by combustible bodies, and a series of experiments are described which
are now among the stock illustrations of the chemical lecture-room.
As to its composition, he says, “taking the mean estimations from the
most accurate experiments, we may conclude that 100 grains of the known
ponderable matter of nitrous oxide consist of about 36·7 oxygen and
63·3 nitrogen”--no very great disparity from modern numbers, viz. 36·4
oxygen and 63·6 nitrogen. He concludes this section with a short review
of the characteristic properties of the combinations of oxygen and
nitrogen, among which he is led to class atmospheric air.
“That the oxygen and nitrogen of atmospheric air exist in
chemical union, appears almost demonstrable from the following
evidences.
“1st. The equable diffusion of oxygen and nitrogen through
every part of the atmosphere, which can hardly be supposed
to depend on any other cause than an affinity between these
principles.
“2dly. The difference between the specific gravity of
atmospheric air, and a mixture of 27 parts oxygen and 73
nitrogen, as found by calculation; a difference apparently owing
to expansion in consequence of combination.”
These “evidences” had already been adduced by others, as stated by
Davy; the first was subsequently disproved by Dalton, the second was
based on inaccurate analyses of air.
To these Davy added two other “proofs” which originated with him:--
“3dly. The conversion of nitrous oxide into nitrous acid, and
a gas analogous to common air, by ignition.
“4thly. The solubility of atmospheric air undecompounded.”
Of these it may be stated that the first is invalid, and the second
not true. Nitrous oxide may, under certain circumstances, give rise
to a mixture of oxygen and nitrogen, but not necessarily in the same
proportion as in common air; and the air boiled out from water has not
the same composition as atmospheric air.
Davy a few years afterwards obtained much clearer views as to the real
nature of the atmosphere, and was, in fact, one of the earliest to
recognise that it is merely a mixture of oxygen and nitrogen.
The third section consists of an account of observations on the
action of nitrous oxide upon animals, and an investigation of the
changes effected in it by respiration; whilst the fourth and last
gives a history of the respirability and of the extraordinary effects
of nitrous oxide, with details of experiments on its powers made by
different individuals.
The last portion of the inquiry--in time of execution the first--is
particularly interesting to the biographer of Davy, not only because
the work in it was originated and carried out by him, but also from the
light it incidentally throws on his character and genius:--
“A short time,” he says, “after I began the study of chemistry,
in March 1798, my attention was directed to the dephlogisticated
nitrous gas of Priestley, by Dr. Mitchell’s Theory of Contagion.”
“Dr. Mitchell,” he tells us in a foot-note, “attempted to prove
from some phenomenon connected with contagious diseases, that
dephlogisticated nitrous gas which he called 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,” he continues, “was soon
demonstrated by a few coarse experiments made on small quantities
of the gas procured from zinc and diluted nitrous [nitric] 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 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.”
In the early part of April, 1799, he obtained nitrous oxide in a state
of purity, and, as already stated, made the attempt to respire it.
“I was aware,” he says, “of the danger of this 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 be possibly 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 immediately injure
the powers of life.”
The experiment was made: the gas passed into the bronchia without
stimulating the glottis, and produced no uneasy feeling in the lungs.
There was a 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. In company with Dr. Beddoes the experiment was
repeated, with the following results:--
“Having previously closed my nostrils and exhausted my lungs,
I breathed four quarts of nitrous oxide from and in to 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 a highly pleasurable thrilling, particularly in the
chest and 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 respiration. 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 langour or exhaustion was consequent,
my feelings throughout the day were as usual, and I passed the
night in undisturbed repose. The next morning the recollections
of the effects of the gas were very indistinct, and had not
remarks written immediately after the experiment recalled them
to my mind I should have even doubted of their reality. I was
willing indeed to attribute some of the strong emotion to the
enthusiasm, which I supposed must have been necessarily connected
with the perception of agreeable feelings, when I was prepared to
experience painful sensations. Two experiments, however, made in
the course of this day, with scepticism, convinced me that the
effects were solely owing to the specific operation of the gas.”
Having thus ascertained the powers of the gas, he made many experiments
to ascertain the length of time it might be breathed with safety, its
action on the pulse, and its general effects on the health when often
respired.
After a number of experiments made to determine its effect in allaying
fatigue, in inducing sleep, or in alleviating the after-effects of
vinous intoxication, he resolved
“to breathe the gas for such a time and in such quantities as to
produce excitement equal in duration and superior in intensity to
that occasioned by high intoxication from opium or alcohol.”
For this purpose he was enclosed in an air-tight or box-chamber, into
which from time to time, by the help of Dr. Kinglake, successive
quantities of twenty quarts of nitrous oxide were introduced. As he
breathed the gas, he found that his temperature and pulse gradually
increased. He experienced a generally diffused warmth without the
slightest moisture of the skin, a sense of exhilaration similar to that
produced by a small dose of wine, and disposition to muscular motion
and to merriment. Luminous points seemed frequently to pass before his
eyes, his hearing became more acute, and he felt a pleasant lightness
and power of exertion in the muscles; and, on account of the great
desire of action, rest was painful. After having been in the box for
an hour and a quarter he began to respire twenty quarts of unmingled
nitrous oxide. What followed is best described in his own words:--
“A thrilling, extending from the chest to the extremities, was
almost immediately produced. I felt a sense of tangible extension
highly pleasurable in every limb; my visible impressions were
dazzling, and apparently magnified, I heard distinctly every
sound in the room, and was perfectly aware of my situation. By
degrees, as the pleasurable sensations increased, I lost all
connection with external things; trains of vivid visible images
rapidly passed through my mind, and were connected with words
in such a manner, as to produce perceptions perfectly novel.
I existed in a world of newly connected and newly modified
ideas: I theorised, I imagined that I made discoveries. When I
was awakened from this semi delirious trance by Dr. Kinglake,
who took the bag from my mouth, indignation and pride were the
first feelings produced by the sight of the persons about me. My
emotions were enthusiastic and sublime, and for a minute I walked
round the room perfectly regardless of what was said to me. As
I recovered my former state of mind I felt an inclination to
communicate the discoveries I had made during the experiment. I
endeavoured to recall the ideas: they were feeble and indistinct;
one collection of terms however presented itself; and with a most
intense belief and prophetic manner, I exclaimed to Dr. Kinglake,
‘_Nothing exists but thoughts! The universe is composed of
impressions, ideas, pleasures and pains!_’”
As might be anticipated, the friend of Coleridge and Southey, himself a
youth of sensibility and poetic feeling, was curious to learn whether
this wonderful gas would increase his stock of the divine afflatus. He
walked amidst the scenery of the Avon, “rendered exquisitely beautiful
by bright moonshine,” and, with a mind filled with pleasurable
feelings, he breathed the gas, and we have as a consequence the
following effusion:--
“Not in the ideal dreams of wild desire
Have I beheld a rapture-wakening form:
My bosom burns with no unhallow’d fire,
Yet is my cheek with rosy blushes warm;
Yet are my eyes with sparkling lustre fill’d;
Yet is my mouth replete with murmuring sound;
Yet are my limbs with inward transports fill’d,
And clad with new-born mightiness around.”
Whether, as the result of this effort, Davy ever again essayed to
tempt the muse when under the influence of nitrous oxide is doubtful.
Nowadays the gas is too frequently associated with unhappy memories of
the dentist’s chair to call up pleasurable associations in a poet’s
mind.
Davy concludes his memoir with some cautious speculations as to the
mode of action of nitrous oxide. That it acts on the blood he was well
aware, but it has been left for subsequent research to determine in
what manner. He points out that “as nitrous oxide in its extensive
operation appears capable of destroying physical pain, it may probably
be used with advantage during surgical operations in which no great
effusion of blood takes place.” As is well known, nitrous oxide is now
one of the commonest anæsthetic agents.
As regards the general question how far the gases are likely to
subserve the interests of medicine, he is very guarded.
“Pneumatic chemistry,” he says, “in its application to medicine
is an art in infancy, weak, almost useless, but apparently
possessed of capabilities of improvement. To be rendered strong
and mature, she must be nourished by facts, strengthened by
exercise, and cautiously directed in the application of her
powers by rational scepticism.”
Davy’s success with nitrous oxide led him to attempt to respire other
gases--such as hydrogen, nitric oxide, carbonic acid--with in one
or two cases almost fatal consequences. On one occasion he tried to
breathe water-gas, made by passing steam over charcoal, and was with
difficulty brought to life again. These deleterious experiments,
carried on with all the ardour and impetuosity of his nature, and
at the expense of much nervous energy, reacted prejudicially on his
health, and he was obliged to seek relaxation and quiet in the pure
atmosphere of his native place.
With the approach of winter he was back again in Bristol, with health
restored and vigour renewed. The following letter to Mr. Davies Gilbert
is interesting as fixing the time at which he entered on the path of
inquiry which was to lead him to his greatest triumphs:--
“Pneumatic Institution, _Oct. 20, 1800_.
“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 hydrocarbonate [the gas obtained by
the action of steam on charcoal]; 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
[nitric] acid is employed. Five plates with nitrous [nitric] 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 remain with sincere respect and affection, yours
“HUMPHRY DAVY.”
To his mother he writes:--
“Hotwells, _November 19, 1800_.
“MY DEAR MOTHER,--Had I believed that my silence of six weeks
would have given you a moment’s uneasiness, I should have written
long ago. But I have been engaged in my favourite pursuit of
experimenting, and in endeavouring to amuse two of my friends
who have spent some days at the Institute. One of them is your
quondam lodger, Gregory Watt, who desired to be kindly remembered
to you and the family....
“Accept my affectionate thanks for your presents. I have received
them all, and I have made a good use of them all. Several
times has a supper on the excellent marinaded pilchards made
me recollect former times, when I sat opposite to you, my dear
mother, in the little parlour, round the little table eating of
the same delicious food, and talking of future unknown things.
Little did I then think of my present situation, or of the mode
in which I am, and am to be, connected with the world. Little did
I then think that I should ever be so long absent from the place
of my birth as to feel longings so powerful as those I now feel
for visiting it again....
“I shall see with heartfelt pleasure the time approaching when
I shall again behold my first home--when I shall endeavour
to repay some of the debts of gratitude I owe to you, to the
Doctor [Tonkin], and to my aunts. My next visit shall not be so
short a one as the last. I will stay with you at least two or
three months. You have let half your house. Have you a bed-room
reserved for me, and a little room for a laboratory? Which part
have you let? When I come to Penzance we will settle all about
John; till then I should like for him to learn French and Latin
with Mr. Dugart. The expense of this or any other part of his
education I will be glad to defray. Do not by any means put him
with Mr. Coryton.... I will write to Kitty in the course of next
month. I am glad to hear Grace is better....
“All in the way of progress goes on nobly. My health was never
better than it has been since I left Cornwall last. I shall be
very glad to hear from you soon. You have a hundred objects to
write about interesting to me. I can only write of myself....
Love to Kitty, Grace, Betsy and John.
“Farewell, my dear mother. I am your affectionate son
“H. DAVY.”
The following letter is to his old friend and benefactor, Mr. John
Tonkin:--
“Dowry Square, Clifton, _Jan. 12, 1801_.
“RESPECTED SIR, ... Natural philosophy has lately been enriched
with many curious discoveries, amongst which galvanism, a
phenomenon that promises to unfold to us some of the laws of our
nature is one of the most important. In medicine, the inoculation
for the cow-pox is becoming general, not in England alone, but
over the whole of Europe; and taking circumstances as they
now stand, it promises gradually to annihilate small-pox. My
discoveries relating to the nitrous oxide, the pleasure-producing
air, are beginning to make some noise; the experiments have
been repeated, with the greatest success, by the professors
of the University of Edinburgh, who have taken up the subject
with great ardour; and I have received letters of thanks and of
praises for my labours from some of the most respectable of the
English philosophers. I am sorry to be so much of an egotist;
yet I cannot speak of the Pneumatic Institution and its success
without speaking of myself. Our patients are becoming daily
more numerous, and our Institution, in spite of the political
odium attached to its founder, is respected, even in the trading
city of Bristol.... I am at this moment very healthy and very
happy; I have had great success in my experiments and I gain a
competence by my pursuits, at the same time that I am (in hopes
at least) doing something towards promoting the public good. If
I feel any anxiety, it is that of being removed so far from you,
my mother, and my relations and friends. If I was nearer, I would
endeavour to be useful to you: I would endeavour to pay some of
the debts of gratitude, I owe to you, my first protector and
earliest friend. As it is, I must look forward to a futurity that
will enable me to do this; but, believe me, wherever I am, and
whatever may be my situation, I shall never lose the remembrance
of obligations conferred on me, or the sense of gratitude which
ought to accompany them.
“I remain, respected Sir, with unfeigned duty and affection, yours
“H. DAVY.”