Davy's Bakerian Lecture of 1808.--Results obtained from
the mutual action of Potassium and Ammonia upon each
other.--His belief that he had decomposed Nitrogen.--He
discovers Telluretted Hydrogen.--Whether Sulphur, Phosphorus,
and Carbon, may not contain Hydrogen.--He decomposes
Boracic acid.--Boron.--His fallacies with regard to the
composition of Muriatic acid.--A splendid Voltaic Battery
is constructed at the Institution by subscription.--Davy
ascertains the true nature of the Muriatic and Oxymuriatic
Acids.--Important chemical analogies to which the discovery
gave origin.--Euchlorine.--Chlorides.--He delivers Lectures
before the Dublin Society.--He receives the Honorary Degree
of LL.D. from the Provost and Fellows of Trinity College.--He
undertakes to ventilate the House of Lords.--The Regent confers
upon him the honour of Knighthood.--He delivers his farewell
Lecture.--Engages in a Gunpowder manufactory.--His marriage.
The third Bakerian Lecture, which Davy read before the Royal
Society in December 1808, is entitled "An Account of some new
analytical Researches on the Nature of certain Bodies, particularly
the Alkalies, Phosphorus, Sulphur, Carbonaceous matter, and the
Acids hitherto undecompounded; with some general Observations on
Chemical Theory."
The object of this lecture was to communicate the results of
numerous experiments which had been instituted for the purpose of
still farther extending our knowledge of the elements of matter,
by the new powers and methods arising from the application of
electricity to chemical analysis.
Important as were the facts thus obtained, they disappointed
the expectation of those who did not consider, that the more
nearly we approach ultimate analysis,[86] the greater must be
the difficulties, the more numerous the fallacies, and the less
perfect the results, of our processes. In fact, his former
discoveries had spoilt us: their splendour had left our organs
of perception incapable of receiving just impressions from any
minor lights, and we participated with exaggerated feelings, in
the disappointment which he himself expressed at several of his
results. The confidence inspired by his former triumphs may be
compared to that which is felt by an army, when commanded by a
victorious General,--a conviction that, however difficult may be
the enterprise, it must be accomplished by the genius of him who
undertakes it. The moment we discovered that Davy was laying siege
to one of Nature's strongest holds,--that he was attempting to
resolve nitrogen into other elementary forms,--we regarded the
deed as already accomplished, and the repulse which followed most
unreasonably produced a feeling of dissatisfaction. Upon such
occasions, the severity of our disappointment will always be in
proportion to the importance of the object we desire to accomplish;
and it is impossible not to feel that the discovery of the true
nature of nitrogen would lead to new views in chemistry, the extent
of which it is not easy even to imagine.
[86] The difficulty of seizing upon elementary forms, as well
as the infinity of combinations of which they are susceptible,
are supposed by Mr. Sankey to be allegorized in the fable of
Proteus, [Greek: Prôteios], being derived from [Greek: prôtos],
signifying the first element. It is not a little singular that
Mr. Leslie, to whom such a speculation was wholly unknown, should
have recognised in the same fable a picture of the cautious
but intrepid advances of the skilful experimenter: he tries
to press Nature into a corner,--he endeavours to separate the
different principles of action,--he seeks to concentrate the
predominant agent, and labours to exclude as much as possible
every disturbing influence. Notwithstanding the confidence
with which modern philosophers have claimed the discovery, the
experimental mode of investigation was undoubtedly known and
pursued by the ancients, who appear, observes Mr. Leslie, to have
concealed their notions respecting it under the veil of allegory.
_Proteus_ signified the mutable and changing forms of material
objects; and the inquisitive philosopher was counselled by the
Poets to watch their slippery demon, when slumbering on the shore
to bind him, and to compel the reluctant captive to reveal his
secrets.--_Elements of Natural Philosophy._
The principal objects of research which this paper embraces
are,--the elementary matter of ammonia; the nature of phosphorus,
sulphur, charcoal, and the diamond; and the constituents of the
boracic, fluoric, and muriatic acids. Enquiries which are continued
and extended in two successive papers, viz. in one read before the
Society in February 1809, entitled "New Analytical Researches on
the Nature of certain Bodies; being an Appendix to his Bakerian
Lecture of 1808;" and in his fourth Bakerian Lecture of 1809,
"On some new Electro-chemical Researches on various Objects,
particularly the Metallic bodies from the Alkalies and Earths; and
on some Combinations of Hydrogen."
With regard to these admirable papers,--for such they must
undoubtedly be considered,--the biographer must confine his
observations to their general character and results. They are far
too refined to admit of a brief analysis, and too elaborate to
allow a successful abridgement. A just idea of their merit can
alone be derived from a direct reference to the Philosophical
Transactions.
The enquiry commences with experiments on the results produced
by the mutual action of potassium and ammonia on each other. His
object was twofold: to refute the hypothesis which assumed hydrogen
as an element of potassium, and to ascertain the nature of the
matter existing in the amalgam of ammonia, or the supposed metallic
basis of the volatile alkali: a question intimately connected with
the whole of the arrangements of chemistry. As to the former point,
it is unnecessary to enter into farther discussion; and with regard
to the latter, it is quite impossible to convey an adequate idea of
the extent of the enquiry: there does not exist in the annals of
chemistry a more striking example of experimental industry.
In the course of his experiments on potassium and ammonia, he
obtained an olive-coloured body, which he was inclined to regard
as a compound of the metallic base of ammonia (_ammonium_) and
potassium; and on submitting which to various trials, he uniformly
obtained, as the product of its decomposition, a proportion of
nitrogen considerably less than that which, upon calculations
founded on a rigid analysis of the volatile alkali, ought to
have been afforded under such circumstances, while the potassium
employed at the same time became oxidated. This result inspired a
hope that nitrogen might have been actually decomposed during the
process, and that its elements were oxygen and a metallic basis, or
oxygen and hydrogen.
That he was sanguine in that hope, appears from the whole tenor
of his paper; in farther proof of which, I can adduce a letter
which he addressed to Mr. Children during the progress of his
experiments, in which he says, "I hope on Thursday to show you
nitrogen as a complete wreck, torn to pieces in different ways."
His subsequent enquiries, however, although they did not strengthen
the suspicion he had formed respecting the decomposition of that
body, yet indirectly developed facts of considerable importance;
which, with his characteristic quickness of perception, he made
subservient to fresh investigation.
His researches into the phenomena exhibited by tellurium, when
forming a part of the Voltaic circuit, are highly interesting. It
had been stated by Ritter, that, of all the metallic substances he
tried for producing potassium by negative electricity, tellurium
was the only one by which he could not procure it; and he uses this
fact in support of his opinion, that potassium is a _hydruret_.
He says, that when a circuit of electricity is completed in water
by means of two surfaces of tellurium, oxygen is given off at the
positive surface, and instead of hydrogen at the negative surface,
a brown powder is formed and separated, which he regards as a
_hydruret_ of tellurium; and he conceives that the reason why
that metal prevents the metallization of potash is, that it has a
stronger attraction for hydrogen than that possessed by the alkali.
Davy's attention was naturally arrested by such a statement,
and, in pursuing the enquiry, he discovered a series of new
facts:--he found that tellurium and hydrogen were capable of
combining, and of forming a gas, to which he gave the name of
_telluretted hydrogen_,--that, so far from tellurium preventing the
decomposition of potash, it formed an alloy with potassium when
negatively electrified upon the alkali--and, such was the intense
affinity of potassium and tellurium for each other, that the
decomposition of potash might be effected by acting on the oxide
of the latter metal and the alkali, at the same time, by heated
charcoal.
With respect to the next subject of enquiry in these papers,
_viz._ whether sulphur, phosphorus, and carbon, in their ordinary
forms, may not contain hydrogen, it would appear that from an
experiment performed by Mr. Clayfield, and which Davy witnessed
at Bristol in the year 1799, he was very early led to suspect the
existence of hydrogen in sulphur; but it was not until 1807, that
he entered upon the investigation of the subject. From the general
tenor of his experiments he concluded that, in its common state,
it may be regarded as a compound, of small quantities of oxygen
and hydrogen, with a large quantity of a basis which, on account
of its strong attractions for other bodies, has not hitherto been
obtained in its pure form. The same analogies apply to phosphorus
and carbon. His conclusion was mainly derived from the fact,
that hydrogen is produced from sulphur and phosphorus in such
quantities by Voltaic electricity, that he thinks it cannot well be
considered as an accidental ingredient in them: the presence of
oxygen, he contends, may be inferred from the circumstance that,
when potassium is made to act upon these bodies, the sulphurets
and phosphurets so formed evolve by the action of an acid less
hydrogen, in the form of compound inflammable gas, than the same
quantity of potassium in an uncombined state. The question,
however, still remains in considerable doubt; and in his "Elements
of Chemical Philosophy," published four years afterwards, he admits
that no accurate conclusions have been formed on the subject.
In his second Bakerian Lecture of 1807, Davy had given an account
of an experiment in which boracic acid appeared to be decomposed
by Voltaic electricity, a dark-coloured inflammable substance
separating from it on the negative surface. In the memoir now
under consideration, he procured the basis by heating together
boracic acid and potassium, when he ascertained it to be a peculiar
inflammable matter, which, after various experiments upon its
nature, he was inclined to regard as metallic; on which account he
proposed for it the name of _Boracium_. At about the same period,
MM. Gay Lussac and Thénard were engaged in investigating the same
subject in France, and they anticipated him in some of the results.
When Davy, by subsequent experiments, had ascertained that the base
of the boracic acid is more analogous to carbon than to any other
substance, he adopted the term _Boron_, as less exceptionable than
that of _Boracium_.
At this time, he also entered upon the investigation of
fluoric acid, the results of which must be reserved for future
consideration.
His experiments and reasonings upon muriatic acid, at this period
of his career, must be now considered as deriving their greatest
degree of interest from their fallacy; and they deserve an
examination in this work, if it be only to estimate the vigour
he subsequently displayed in disentangling himself from a web of
his own fabrication. The most satisfactory proof of intellectual
strength is to be found in the existence of a power which enables
the mind to conquer its prejudices and to correct its own errors.
How many remarkable instances does the history of science present,
in which the philosopher has treated his facts as Procrustes did
his victims, in order that they might accord with the measure most
convenient for his purpose!
Prejudiced by the general opinion respecting the hitherto
undecompounded nature of muriatic acid, he had long sought to
discover its radical by the agency of Voltaic electricity; but he
uniformly found that when its aqueous solution was thus acted upon,
the water alone underwent decomposition; while the electrization
of the gas afforded no other indication of its nature than the
presence of a much greater quantity of water than theory had
assigned to it. He proceeded, therefore, to examine the acid by
other modes of enquiry: he found, by the action of potassium upon
the gas, that a large volume of hydrogen was evolved, which,
in conjunction with other experiments, satisfied him that this
body, in its common aëriform state, contained at least one-third
of its weight of water; and he adopted various expedients with
the hopes of obtaining the acid free from it. Without pursuing
him through this research, I shall merely state the conclusions
at which he arrived, _viz._ that dry muriatic acid, could it be
obtained, would probably be found to possess the strongest and most
extensive powers of combination of all known substances belonging
to the class of acids; and that its basis, should it ever be
separated in a pure form, will be one of the most powerful agents
in Chemistry. From the fact of water appearing in a separate state,
and oxymuriatic acid being formed whenever a metallic oxide was
heated in muriatic acid gas, he was led to consider the muriatic
acid as a compound of a certain base, (not hitherto obtained in a
separate state,) and not less than one-third part of water; while
he regarded oxymuriatic acid as a compound of the same base (free
from water) with oxygen.
After the numerous experiments in which the original battery
of the Institution had been used, so greatly were its metallic
plates corroded, that it was found to be no longer serviceable;
in consequence of which, as it would appear from a minute, dated
July 11, 1808, "Mr. Davy laid before the Managers of the Royal
Institution the following paper, _viz._
"A new path of discovery having been opened in the agencies of
the electrical battery of Volta, which promises to lead to the
greatest improvements in Chemistry and Natural Philosophy, and the
useful arts connected with them; and since the increase of the
size of the apparatus is absolutely necessary for pursuing it to
its full extent, it is proposed to raise a fund by subscription,
for constructing a powerful battery, worthy of a national
establishment, and capable of promoting the great objects of
science.
"Already, in other countries, public and ample means have been
provided for pursuing these investigations. They have had their
origin in this country; and it would be dishonourable to a nation
so great, so powerful, and so rich, if, from the want of pecuniary
resources, they should be completed abroad.
"An appeal to enlightened individuals on this subject can scarcely
be made in vain. It is proposed that the instrument and apparatus
be erected in the Laboratory of the Royal Institution, where it
shall be employed in the advancement of this new department of
science."
The Minute goes on then to state that--
"The above paper having been laid before the Board of Managers,
they felt it their indispensable duty instantly to communicate
the same to every member of the Royal Institution, lest the
slightest delay might furnish an opportunity to other countries for
accomplishing this great work, which originated in the brilliant
discoveries recently made at the Royal Institution.
"The Managers present agree to subscribe to this undertaking.
"ORDERED, that a book be opened at the Steward's office for the
purpose of entering the names of all those members who may wish to
contribute towards this important National object."
To the great gratification of Davy, and to the honour of the
country, the list of subscribers was soon completed, and one of the
most magnificent batteries ever constructed was speedily in full
operation.
It is thus alluded to in his Elements of Chemical Philosophy:--"The
most powerful combination that exists, in which number of
alternations is combined with extent of surface, is that
constructed by the subscriptions of a few zealous cultivators and
patrons of science, in the Laboratory of the Royal Institution. It
consists of two hundred instruments connected together in regular
order, each composed of ten double plates arranged in cells of
porcelain, and containing in each plate thirty-two square inches;
so that the whole number of double plates is two thousand, and the
whole surface one hundred and twenty-eight thousand square inches."
This battery, when the cells were filled with sixty parts of water
mixed with one part of nitric acid, afforded a series of brilliant
and impressive effects. When pieces of charcoal, about an inch
long, and one-sixth of an inch in diameter, were brought near
each other, (within the thirtieth or fortieth parts of an inch,)
a bright spark was produced, and more than half the volume of the
charcoal became ignited to whiteness, and by withdrawing the points
from each other a constant discharge took place through the heated
air, in a space equal at least to four inches, producing a most
brilliant ascending arch of light, broad and conical in form in
the middle. When any substance was introduced into this arch, it
instantly became ignited; platina melted as readily in it as wax
in the flame of a common candle; quartz, the sapphire, magnesia,
lime, all entered into fusion; fragments of diamond, and points of
charcoal and plumbago rapidly disappeared, and seemed to evaporate
in it, even when the connexion was made in a receiver exhausted by
the air-pump; but there was no evidence of their having previously
undergone fusion.
All the phenomena of chemical decomposition were produced with
intense rapidity by this combination. When the points of charcoal
were brought near each other in non-conducting fluids, such as
oils, ether, and oxymuriatic compounds, brilliant sparks occurred,
and elastic matter was rapidly generated.
Among the numerous experiments performed by the aid of this
battery, he instituted several, in the hope of decomposing
nitrogen; and which are recorded in his Bakerian Lecture of 1809.
He ignited potassium, by intense Voltaic electricity, in this gas;
and the result was, that hydrogen appeared, and some nitrogen was
found deficient. This, on first view, led him to the suspicion that
he had attained his object; but, in subsequent experiments, in
proportion as the potassium was more free from a coating of potash,
which necessarily introduced water, so in proportion was less
hydrogen evolved, and less nitrogen found deficient. The general
tenor of these enquiries, therefore, did not strengthen the opinion
he had formed with respect to the compound nature of nitrogen.
It appears from the following letter, that Davy visited his friend
Mr. Andrew Knight at Downton, in September 1809. It is introduced
in these memoirs principally for the purpose of showing with what
boldness he was accustomed to depart from generally received
opinions, and to project new theories for the explanation of the
most abstruse subjects.
TO JOHN GEORGE CHILDREN, ESQ.
September 23, 1809.
MY DEAR FRIEND,
I am about to visit Downton, and shall return by the first of
October. I have neither seen nor heard from Lord Darnley, and I
conjecture he has not yet returned from Scotland.
I wish you great sport in pheasant-shooting, but I trust you have
had still nobler game in your Laboratory.
I doubt not you have found before this, as I have done, that the
substance we mistook for _sulphuretted_ hydrogen is _telluretted_
hydrogen, very soluble in water, combinable with alkalies and
earths, and a substance affording another proof that hydrogen is
an oxide. I have met with another analogous compound, that of
_boracium_ with hydrogen, which possesses very similar properties.
I find that taking _ammonium_ as the basis of hydrogen, according
to the ideas which I stated, all the compounds will agree with the
suppositions that I mentioned to you, _viz._ eight cubic inches
of hydrogen, two of oxygen, ammonia; four and two, water; four
and four, nitrogen; four and six, nitrous oxide; four and eight,
nitrous gas; four and ten, nitric acid. Where the multiples are not
in geometrical order, the decomposition is most easy, _i.e._ in
nitrous oxide and nitric acid; more easy in water than in ammonia;
but most difficult in nitrogen, where there is probably the most
perfect equilibrium of affinities.
I have kept charcoal white hot by the Voltaic apparatus, in
dry oxymuriatic acid gas for an hour, without effecting its
decomposition. This agrees with what I had before observed with a
red heat. It is as difficult to decompose as nitrogen, except when
all its elements can be made to enter into new combinations.
I find the radiation, _in vacuo_, from ignited platina, is to that
in air as three to one:--so much for Leslie's hypothesis.
A little electrical machine acts with a repulsion as two, in a
vacuum equal to five inches of mercury; as thirty, in common air;
as thirty, in oxygen; as twenty-nine or thirty, in hydrogen;
and as forty-five, in carbonic acid. I showed this experiment,
made with every precaution, to Mr. Cavendish, Dr. Herschell, Dr.
Wollaston, and Warburton: so much for the theory, that electricity
is dependent upon oxidation. I do not think our worthy friend Pepys
will resist any longer.
Pray let me know what you have been doing. I hope you will not
suffer these beautiful and satisfactory experiments of the
capacities of metals to remain still. Write me a letter as
egotistical as the one I have given you. You are pledged to do good
and noble things, and you must not disappoint the men of science of
this country.
With kindest remembrances to your excellent father, and with hopes
that we shall soon meet, I am, my dear friend,
Very faithfully and affectionately yours,
H. DAVY.
The genius displayed by Mr. Knight in investigating the phenomena
of vegetable nature, and in applying the knowledge thus acquired
to objects of practical improvement, excited in Davy, as might
have been expected, feelings of the highest admiration; and when,
in addition to such claims, he was the acknowledged patron and
hospitable friend of the angler, the reader will readily imagine
the warmth of feeling with which our philosopher cherished his
friendship.
On commencing the present work, I applied to Mr. Knight for any
assistance he might be able to afford me, in aid of so arduous a
labour; and he very kindly returned an answer, from which I extract
the following passage.
"My late lamented friend, Sir Humphry Davy, usually paid me a
visit in the autumn, when he chiefly amused himself with angling
for grayling, a fish which he appeared to take great pleasure in
catching. He seemed to enjoy the repose and comparative solitude of
this place, where he met but few persons, except those of my own
family, for we usually saw but little company. He always assured me
that he passed his visits agreeably, and I had reason to believe he
expressed his real feelings.
"In the familiar conversations of these friendly visits, he always
appeared to me to be a much more extraordinary being than even his
writings, and vast discoveries, would have led me to suppose him;
and, in the extent of intellectual powers, I shall ever think that
he lived and died without an equal."
The reader has already been made acquainted with those experiments
which led Davy to modify the prevailing opinions, with regard to
the constitution of the muriatic and oxymuriatic acids; and on the
false assumption that oxygen existed in the latter gas, to refer
the deposition of water which takes place upon heating a metallic
oxide in the former, to the supposition that muriatic acid contains
a large proportion of water as essential to its composition.
Upon observing, however, that charcoal, if freed from hydrogen
and moisture, even when ignited to whiteness in oxymuriatic, or
muriatic acid gas, by the Voltaic battery, did not effect the least
change in them, he was led to suspect the accuracy of his previous
conclusion; and on retracing his steps, and entering upon a new
path of enquiry, he ultimately succeeded, after one of the most
acute controversies that ever sprang from a chemical question,
in recalling philosophers to the original theory of Scheele, by
establishing the important truth, that oxymuriatic acid is, in the
true logic of chemistry, a simple body, which becomes muriatic acid
by its union with hydrogen.
The new views arising out of such a revolution in chemical opinion
are certainly not the least important of those to which the
discoveries of Davy have given birth. Dr. Johnson has remarked,
that "one of the most hazardous attempts of criticism is to choose
the best amongst many good." I am much mistaken, however, if the
chemists of Europe will not, without hesitation, pronounce his
researches into the nature of oxymuriatic acid, and its relations,
with the exception of those by which he established the chemical
laws of Voltaic action, to be by far the most important of all his
labours; not only as evincing the ascendancy of his genius, and the
steadiness of his perseverance, but as marking a new and splendid
era in chemical science.
It is much more difficult to eradicate an ancient error than to
establish a new truth; and on this occasion, he had not only to
contend against the pampered errors of a domineering system, but
against the equivocal and illusive evidence, or, if I may be
allowed the expression, the apparent neutrality of facts by which
the truth of his theory was to be judged. In consequence of the
constant and often unsuspected interference of water, there is
scarcely a result connected with the chemical history of the bodies
in dispute, that did not admit of being equally well explained upon
the hypothesis that oxymuriatic acid is a compound, as upon that
of its being a simple or undecompounded substance. The question
could never have been determined but by an investigation of the
most refined and subtile nature; so delicately was the evidence
balanced, that nothing but the keenest eye, and the steadiest hand,
could have determined the side on which the beam preponderated.
The illustrious discoverer of oxymuriatic acid considered that body
as muriatic acid freed from hydrogen, or, in the obscure language
of the Stahlian school, as muriatic acid deprived of phlogiston,
whence he assigned to it the name of _dephlogisticated_ muriatic
acid. Upon the establishment of the antiphlogistic theory by
Lavoisier, it became essential to the generalization which
distinguished it, that a body performing the functions of an acid,
and above all, supporting the process of combustion, should be
regarded as containing oxygen in its composition; and facts were
not wanting to sanction such an inference. The substance could
not even be produced from muriatic acid, without the action of
some body known to contain oxygen; while the fact of such a body
becoming deoxidated by the process, seemed to demonstrate, beyond
the possibility of error, that the conversion of the muriatic into
the oxymuriatic acid, was nothing more than a simple transference
of oxygen from the oxide to the acid: an opinion which was
universally adopted, and which for nearly thirty years triumphed
without opposition.
The body of evidence by which Davy overthrew this doctrine, and
established the undecompounded nature of oxymuriatic acid, is to
be found in a succession of papers read before the Royal Society,
_viz._ in that already announced,--in his Bakerian Lecture for
1810,--and in a subsequent memoir read in February 1811.
It will be impossible for me to follow the author through all the
intricacies of the enquiry; but I shall seize upon some of its more
prominent points, and give a general outline of its bearings.
No sooner had his suspicions been excited with regard to the
compound nature of oxymuriatic acid, than it occurred to him that,
if oxygen were really present in that body, he might readily obtain
it from some of its compounds; that, for instance, its combination
with tin would yield an oxide of that metal by ammonia; while
those with phosphorus would furnish, on analysis, either the
phosphor_ous_, or phosphor_ic_ acid. But after experiments in which
the presence of water was most cautiously excluded, the results he
had anticipated were not obtained. In the place of an oxide of tin,
the product, on the application of heat, volatilized in dense and
pungent fumes; and, instead of obtaining an acid of phosphorus, a
body possessing new and unexpected properties resulted. Again,--it
had been stated, in confirmation of the theory that recognised the
presence of oxygen in oxymuriatic acid, that when this latter body
and ammonia were made to act upon each other, water was formed: our
chemist frequently repeated the experiment, and convinced himself
that such was not the fact.
It had been shown by Mr. Cruickshank, and more recently proved by
MM. Gay Lussac and Thénard, that oxymuriatic acid and hydrogen,
when mixed in nearly equal proportions, produce a matter almost
entirely condensable by water, which is common muriatic acid;
and that water is not deposited in the operation. Davy made many
experiments on the subject, and he found, that when these gases
were mingled together in equal volumes over water, introduced into
an exhausted vessel, and fired by the electric spark, muriatic acid
resulted, although, at the same time, there was a certain degree of
condensation, and a slight deposition of vapour; but on repeating
the experiment in a manner still more refined, and by carefully
drying the gases, such condensation became proportionally less.
When, in addition to the above experimental evidence, it is stated
that MM. Gay Lussac and Thénard had proved, by a copious collection
of instances, that in the usual cases where oxygen is eliminated
from oxymuriatic acid, water is always present, and muriatic acid
gas is formed; and as it has been moreover shown that oxymuriatic
is converted into muriatic acid gas by combining with hydrogen, it
is scarcely possible to avoid the conclusion, that the oxygen is
derived from the decomposition of water, and not from that of the
acid.
When mercury is made to act, by means of Voltaic electricity, upon
one volume of muriatic acid gas, all the acid disappears, calomel
is formed, and half a volume of hydrogen is evolved.
By such experiments and arguments, Davy was led to the conclusion
that, as yet, oxymuriatic acid has not been decompounded; that it
is a peculiar body, elementary as far as our knowledge extends, and
analogous, in its tendency of combination with inflammable matter,
to oxygen gas; that, in fact, it may be a _peculiar_ acidifying and
dissolving principle, forming with different substances compounds
analogous to acids containing oxygen, or to oxides, in their
properties and powers of combination, but differing from them in
being, for the most part, decomposable by water. On this idea, he
thinks that muriatic acid may be considered as having hydrogen for
its base, and oxymuriatic acid for its acidifying principle. In
confirmation of such an opinion, it is also important to remark,
that in its electrical relations, oxymuriatic acid maintains its
analogy to oxygen.
The vivid combustion of bodies in oxymuriatic acid gas, Davy
acknowledges, may, at first view, appear a reason why oxygen should
be admitted as one of its elements; but he answers this argument
by stating, that heat and light are merely results of the intense
agency of combination; and that sulphur and metals, alkaline earths
and acids, become alike ignited under such circumstances.
As change of theory with regard to the primitive must necessarily
modify all our views with respect to the nature of secondary
bodies, so must this new view of oxymuriatic acid affect all our
opinions respecting its compounds. Davy accordingly proceeded, in
the first place, to investigate the various bodies which had been
distinguished by the name of _hyper-oxymuriates_, _muriates_, &c.
It also became necessary to alter the nomenclature, since to call
a body which neither contains oxygen nor muriatic acid, by a term
which denotes the presence of both, is contrary to those very
principles which first suggested it. Having consulted some of the
most eminent philosophers, Davy proposed a name founded upon one of
the most obvious and characteristic properties of the oxymuriatic
acid, namely, its colour, and called it CHLORINE.
If then oxymuriatic acid, or chlorine, does not contain any oxygen,
a question immediately arises as to the true nature of those
compounds in which the muriatic acid has been supposed to exist in
combination with a much larger proportion of oxygen than in the
oxymuriatic acid,--in the state in which it has been named by Mr.
Chenevix _hyper-oxygenized_ muriatic acid.
In his Bakerian Lecture of 1810, entitled, "On some of the
Combinations of Oxymuriatic Gas and Oxygen, and on the Chemical
Relations of these Principles," he details a number of experiments
for the illustration of this subject, and arrives at the
conclusion, that the oxygen in the hyper-oxymuriate of potash is
in triple combination with the metal and chlorine. He likewise
confirms his views, with regard to the elementary nature of
this latter body, by a series of new enquiries, and shows that
they are not incompatible with known phenomena:--for instance,
Scheele explained the bleaching powers of oxymuriatic gas, by
supposing that it destroyed colours by combining with _Phlogiston_.
Berthollet[87] considered it as acting by imparting oxygen; Davy
now proves that the pure gas is wholly incapable of altering
vegetable colours, and that its operation in bleaching entirely
depends upon its property of decomposing water, and of thus
liberating its oxygen.[88] The experiment by which he demonstrated
this fact is so simple and satisfactory, that I shall here relate
it. Having filled a glass globe, containing dry powdered muriate of
lime, with oxymuriatic gas, he introduced into another globe, also
containing muriate of lime, some dry paper tinged with litmus,
that had been just heated; by which device the intrusion of
moisture was effectually prevented. After some time, this latter
globe was exhausted, and then connected with that containing the
oxymuriatic gas, and by an appropriate set of stop-cocks, the paper
was exposed to the action of the gas thus dried: no change of
colour in the test paper took place, and after two days, there was
scarcely a perceptible alteration; while some similar paper dried
and introduced into the gas, that had not been exposed to muriate
of lime, was instantly bleached.
[87] Berthollet first applied oxymuriatic acid for the purpose
of bleaching, in France; from whence Mr. Watt introduced it into
England.
[88] Dr. Thomson has more recently explained the operation,
by supposing that water is decomposed, and that its hydrogen
goes to the chlorine, and its oxygen to the water, forming with
the latter a deutoxide of hydrogen, or the oxygenated water of
Thénard, which he considers as the true bleaching principle.
As an illustration of the eagerness with which he seized upon
facts, in order to apply them to economical purposes, it may be
stated that, on reflecting upon the theory of bleaching, and on
the changes which its agents undergo, he was led to propose the
use of a liquor produced by the condensation of oxymuriatic gas in
water, containing magnesia diffused through it, as superior to the
oxymuriate of lime commonly employed.[89]
[89] Experience has not confirmed the value of this suggestion.
Davy imagined that the vegetable fibre was injured by the
saline residuum; and having found that muriate of magnesia was
less corrosive than muriate of lime, he was led to propose
the substitute above stated. The fact, however, is, that the
fibre is injured by the chlorine; and as this body has only a
slight affinity for magnesia, it too quickly abandons it; and
consequently the oxymuriate of lime is still preferred.
It has been very truly observed, that all knowledge which is gained
tends towards the acquisition of more, just as the iron dug from
the mine facilitates in return the working of the miner. Never
was this truth more forcibly illustrated than by the discovery of
the nature of chlorine. In the progress of that train of enquiry,
which became necessary for the adjustment of our views as they
regarded the combinations of that body, Davy discovered a series of
new compounds, the history of which he communicated in successive
papers to the Royal Society.
In a memoir read in February 1811, entitled, "On a Combination
of Oxymuriatic Gas and Oxygen Gas," he announced the existence
of a _protoxide_ of chlorine, under the name of _Euchlorine_;
and in a communication from Rome in the year 1815, he described
another compound of chlorine and oxygen, containing a still larger
proportion of this latter element, and which has since been made
the subject of a series of experiments by Count Stadion of Vienna.
As it does not exhibit any acid properties, Dr. Henry proposes
to call it a _Peroxide_, in preference to _Deutoxide_; thinking
it probable that intermediate compounds, between this and the
protoxide already mentioned, may be hereafter discovered.
His paper on _euchlorine_ abounds with interest. He found that
by acting on the salts formerly denominated _hyper-oxymuriates_,
by muriatic acid, the gas evolved differed very greatly in its
properties, with the different modes of preparing it. When
much acid was employed with a small quantity of the salt, and
the gas was collected over water, it was not found to differ
from oxymuriatic gas; but when, on the other hand, the gas was
procured by means of a weak acid, and a considerable excess of
the salt, at a low heat, and was collected over mercury, it
possessed properties essentially different. Its colour, under such
circumstances, was of a dense tint of brilliant yellow-green,
whence the name of _euchlorine_.[90] When in a pure form, this gas
is so readily decomposed, that it will sometimes explode during the
time of its transfer from one vessel to another, producing both
heat and light with an expansion of volume,[91] and it may always
be made to explode by a very gentle heat, often even by that of the
hand.
[90] From [Greek: eu] and [Greek: chlôros].
[91] The most vivid effects of combustion known are those
produced by the _condensation_ of oxygen, or chlorine: but
in this instance, a violent explosion with heat and light is
produced by their separation, and _expansion_; a perfectly novel
circumstance in chemical philosophy.
The results of its explosion indicate its composition to be one
atom of chlorine, and one of oxygen. None of the metals that burn
in chlorine act upon this gas at common temperatures; but when the
oxygen is separated, they then inflame in the residual chlorine.
This fact Davy illustrated by a series of experiments, one of
which, from its extreme beauty, I shall here relate. If a glass
vessel, containing copper-leaf, be exhausted, and the euchlorine
afterwards admitted, no action will take place; but throw in a
little nitrous gas, and a rapid decomposition will ensue, and the
metal will burn with its accustomed brilliancy.
The discovery of this interesting gas, and that of the facts
connected with it, not only confirmed the novel views with regard
to the elementary nature of chlorine, but they reconciled the
contradictory accounts of different authors respecting the
properties of that body.
The weak attraction subsisting between the elements of this
compound gas, which by a comparatively low temperature are made
repulsive of each other, confirms also the supposition of Davy,
that oxygen and chlorine belong to the same class of bodies.
The discovery of the _peroxide of chlorine_ was made during an
examination of the action of acids on the _hyper-oxymuriates_ of
Chenevix, undertaken by Davy in consequence of a statement of
M. Gay Lussac, that a peculiar acid, which he called _chloric
acid_, might be procured from the _hyper-oxymuriate of baryta_ by
sulphuric acid. With regard to this acid, which its discoverer
considered as composed of one atom of chlorine and five atoms of
oxygen, Davy entered into a warm controversy, affirming that the
fluid in question owed its acid powers to combined hydrogen; and
that it was analogous to the other hyper-oxymuriates, as being
triple compounds of inflammable bases with chlorine and oxygen, in
which the two former determine the character of the compound: this
opinion, however, he afterwards abandoned, and I have reason to
believe that he regretted ever having advanced it.
Amidst these new views, it became necessary to alter our opinions
with regard to many of those compounds which have been termed
_muriates_, but which, it would appear, contain neither muriatic
acid nor oxygen, but are, strictly speaking, combinations of metals
with chlorine, held in union by a very powerful affinity, since
chlorine is capable of expelling the whole of the oxygen from any
metallic oxide, and of taking its place; even those metals that
are most distinguished by their affinity for oxygen, abandon it
whenever their oxides are heated in chlorine, in which case oxygen
gas is disengaged.
The same metal is also capable of uniting with different
proportions of chlorine, which, so far as has been yet ascertained,
are definite, and in no case exceed two proportions to one of
metal. Hence it was proposed by Davy, in fixing the nomenclature of
these compounds, to designate such as contain the least proportion
of chlorine by the termination _ane_, added to the Latin name
of the metal, as _cuprane_ for that of copper; those containing
the larger proportion of chlorine, by the termination _anea_,
as _cupranea_. The chemical name of our common culinary salt,
in conformity with such a nomenclature, would be _sodane_. This
proposition, however, has not been adopted;[92] the compounds
of metals and chlorine are either called _chlorurets_, or what
is preferable, from their analogy with the similar compounds
of oxygen, _chlorides_, and which are further distinguished as
_protochlorides_, _deutochlorides_, &c.
[92] A little reflection will convince us that such a
nomenclature could never have been adopted with propriety. It
is in direct defiance of the Linnæan precept, that a specific
name must not be united to the generic as a termination; besides
which, such terms could never have been preserved in translations
into other languages.
In connexion with the history of these chlorides, a question
arises of great interest and obscurity, and which has engaged the
attention of some of our most distinguished chemists,--whether
such a body, when dissolved by water, remains as a chloride; or,
by decomposing that fluid, and combining with its elements, is
not immediately converted into a muriate? With respect to several
of these chlorides, no doubt can be entertained as to the fact of
their decomposing water; for instance, the chloride of phosphorus
is thus acted upon, the oxygen of the water forms phosphorous acid
with the phosphorus, while its hydrogen unites with the chlorine
to form muriatic acid; and as those products are such as do not
combine with each other, but exist in a state of mixture in the
water, each may be recognised by its peculiar properties. In like
manner, as Davy has observed, when water is added in certain
quantities to Libavius's liquor (_deutochloride of tin_), a solid
crystalline mass is obtained, from which oxide of tin and muriate
of ammonia can be obtained by ammonia.
In his Elements of Chemical Philosophy, Davy has been, in many
instances, explicit on this point; and his opinions are favourable
to the idea that chlorides become muriates by being dissolved in
water: thus, he states that the perchloride of iron "acts with
violence upon water, and forms a solution of red muriate of iron;"
and he observes that the permuriate "forms a solution of green
muriate of iron by its action upon water."[93] With regard,
however, to the general principle, that chlorides become muriates
by solution, there are difficulties which do not fall within
the province of a biographer to discuss. I shall merely observe
that such a change is, in many cases, so inconsistent with our
preconceived opinions, that very strong evidence is required to
reconcile us to its truth. We are undoubtedly prepared to hear that
much may happen between the cup and the lip,--but that common salt
should be a _chloride of sodium_ on our plates, and a _muriate of
soda_ in our mouths, is certainly a very startling assertion.
[93] For an admirable paper upon this subject by Mr. R. Phillips,
in which all the material points of the subject are considered
with that acumen which distinguishes its author, see Annals of
Philosophy, vol. i. New Series.
The reception which the chloridic theory met with from the chemical
world might aptly enough be adduced in illustration of that remark
with which I commenced the preceding chapter. At first, its
truth was questioned, and no sooner had this been triumphantly
established, than an attempt was invidiously made to transfer the
glory of the discovery from Davy to the French philosophers. Upon
each of these points, I shall beg to offer a few observations.
First, with regard to the fact of chlorine being as yet an
undecompounded body. The very announcement of a theory so
adverse to the universal faith of Europe, was a signal for open
hostilities; the observations of Dr. Murray may be considered as
expressing the sentiments of most of the leading chemists on the
first publication of the novel views of Davy. "Opinions," says
he, "more unexpected have seldom been announced to chemists, than
those lately advanced by Mr. Davy with regard to the constitution
of the muriatic and oxymuriatic acids; _viz._ that the latter is
not a compound of muriatic acid and oxygen, but a simple substance,
and that the former is a compound of this substance with hydrogen.
The more general principle connected with these opinions, that
oxymuriatic acid is, like oxygen, an acidifying element, forming
with inflammables and metals an extensive series of analogous
compounds, leads still more directly to the subversion of the
established chemical systems, and to an entire revolution in some
of the most important doctrines of the science."
Dr. Murray entered the lists as the avowed partisan of the theory
of Berthollet; Dr. Davy, on the other hand, appeared as the
champion of his brother's doctrine. A severe contest ensued, and
both combatants displayed equal skill and strength. The object
of the former was to demonstrate the presence of water, or its
elements, as a constituent part of muriatic acid; and he proposed
to determine the point by combining the dry gases of muriatic acid
and ammonia; for as these bodies did not contain its elements,
should water appear, he maintained that it must be considered as
pre-existing in the muriatic acid; while, on the contrary, if no
water could be procured, it would be unphilosophical to suppose
it present, but that muriatic acid gas must, in that case, be
considered as a compound of hydrogen and chlorine. In performing
this experiment, Dr. Murray did succeed in obtaining a portion of
water; but the inference from such a fact was questioned on the
other side, upon the assumption of the humidity of the gases. As
all parties, however, seemed to agree, that if every source of
error could be excluded, the combination of these gases would
furnish an _experimentum crucis_, by which the truth or fallacy
of either theory might be established, Davy, when at Edinburgh,
was desirous of repeating the experiment with Dr. Hope, and it was
accordingly made in the College Laboratory. Sir George Mackenzie,
Mr. Playfair, and some other gentlemen, were present. The results
were communicated in Nicholson's Journal by Dr. Davy, and may be
briefly stated as follows:--The alkaline and acid gases were pure,
and both had been previously dried by exposure for sixteen hours
to substances having a strong attraction for water. The apparatus
consisted of a plain retort of about the capacity of twenty-six
cubic inch measures, with a stop-cock; and of a receiver, with a
suitable stop-cock. The latter was filled over mercury with one
of the gases, which from the receiver passed into the exhausted
retort by means of the stop-cocks; the other gas was introduced the
same way into the retort; and thus alternately about ninety cubic
inches of each gas were combined. All the salt having then been
driven into the bulb of the retort by the heat of a spirit lamp,
the neck was cooled and kept cold by moistened cloths, whilst the
bulb was heated by a coke fire, till the muriate began to sublime,
and to make its appearance at the curvature of the vessel when
the fire was withdrawn. The result was then examined, while the
bottom of the retort was still very hot: a dew, just perceptible,
was observed lining the cold neck. The quantity of water was so
extremely small, that the globular particles composing this dew
could scarcely be perceived by the naked eye; now the quantity
of water, according to hypothesis, should equal no less than
eight grains. There is no small difference, it must be confessed,
between that quantity and a dew barely perceptible, and which may
reasonably be referred to a minute quantity of vapour in the gases,
or to a little moisture derived from the mercury, a small quantity
of which entered the retort with the gases. Dr. Hope wished to
ascertain how much water would produce such a dew as was observed.
For this purpose he heated in a retort, of a similar size to that
used in the experiment, a single drop of water, which it may be
said weighs about a grain. The appearance of condensed water, in
this instance, in the neck of the retort, was much greater than in
the preceding: he considered it as being three or four times as
great.[94]
[94] Sir Humphry Davy, during some experiments on the diamond,
subsequently ascertained that less than 100th of a grain of water
is sufficient to produce a sensible dew on a polished surface.
From these results it may be concluded, on Dr. Murray's own ground
of reasoning, that water is not a constituent part of muriatic
acid gas, and that this substance is a compound merely of chlorine
and hydrogen; for it is easy to account for the presence of about
one-third of a grain of water from various sources, while it is
impossible to account for the absence of eight grains upon any
theory except that which supposes the gas to be _anhydrous_.
I shall not pursue the numerous other experiments by which it was
attempted to prove the fallacy of Davy's views; they all turn upon
the same point, and were refuted by the same vigorous methods of
enquiry. The chloridic theory may therefore now be considered as
fully established: the philosophers who were for so long a period
hostile to its reception, have at length yielded their assent; and
Berzelius, in a paper published in the "Annales de Chimie," on the
subject of sulpho-cyanic acid, has unconditionally tendered his
allegiance; while the subsequent discovery of iodine and bromine
has confirmed, by the most beautiful analogies, the views so
satisfactorily explained by experiment.
As to the claim of priority which has been urged by several
philosophers in favour of the French chemists, Davy, in speaking
of Gay Lussac's paper, published in the "Annales de Chimie" for
July 1814, observes, that "the historical notes attached to it are
of a nature not to be passed over without animadversion. M. Gay
Lussac states, that he and M. Thénard were the first to advance
the hypothesis that chlorine was a simple body; and he quotes M.
Ampère as having entertained that opinion before me. On the subject
of the originality of the idea of chlorine being a simple body, I
have always vindicated the claims of Scheele; but I must assume
for myself the labour of having demonstrated its properties and
combinations, and of having explained the chemical phenomena it
produces; and I am in possession of a letter from M. Ampère, that
shows he has no claims of this kind to make."[95]
[95] Royal Institution Journal, vol. i. p. 283.
The question of priority appears to me to be readily settled by a
reference to printed documents. Davy published his "Elements of
Chemical Philosophy" in 1812, containing a systematic account of
his new doctrines concerning the combinations of simple bodies.
Chlorine is there placed in the same rank with oxygen, and finally
removed from the class of acids. In 1813, M. Thénard published
the first volume of his "Traité de Chimie Elémentaire Théorique
et Pratique," in which he states the composition of oxymuriatic
acid as follows:--"_Composition_. The oxygenated muriatic gas
contains the half of its volume of oxygen gas, not including that
which we may suppose in muriatic acid." It was not until the year
1816, that, by a note in his fourth volume, he appears to have
at all relaxed in his attachment to the old theory of Lavoisier
and Berthollet; and it will presently appear, that at the period
above mentioned, iodine had been discovered, and its analogies to
chlorine fully established, by the sagacity of Davy.
Having, as I trust, offered an impartial view of his claims to the
establishment of the chloridic theory, I shall resume my narrative
of those events which more immediately connect themselves with his
personal history at this period.
The great fame of Davy, and the high importance of the discoveries
which had bestowed it, became a general theme of admiration
throughout the scientific circles of Europe, and induced the
members of the Dublin Society to invite him to that city, for the
purpose of delivering a course of lectures. From the authentic
documents which have been placed in my hands, I am enabled to give
a particular account of this transaction.
At a meeting of the Dublin Society held on the 3rd of May 1810,
the following Resolutions were proposed and unanimously carried,
_viz._
1. "That it is the wish of the Society to communicate to the
Irish public, in the most extended manner consistent with the
other engagements of the Society, the knowledge of a Science so
intimately connected with the improvement of Agriculture and the
Arts, which it is their great object to promote; and that, with
this view, it appears to them extremely desirable to obtain the
fullest information respecting the recent discoveries made by Mr.
Davy, in Electro-chemical science.
2. "Resolved, That application be made to the Royal Society,
requesting that they will be pleased to dispense with the
engagements of Mr. Davy, so far as to allow the Dublin Society to
solicit the favour of his delivering a course of Electro-chemical
Lectures in their new Laboratory, as soon as may be convenient
after their present course of chemical lectures shall have been
completed by their Professor Mr. Higgins.
3. "That the sum of four hundred guineas be appropriated out
of the funds of the Society, to be presented to Mr. Davy, as a
remuneration for the trouble and expense which they propose he
should incur, and as a mark of the importance they attach to the
communication which they solicit."
Mr. Leslie Foster having stated to the Dublin Society that the
"Farming Society of Ireland" were desirous of availing themselves
of this opportunity to apply to Mr. Davy to repeat before them
the six lectures on the application of chemistry to agriculture,
which he delivered this year (1810) to the Board of Agriculture
in England, and that they requested the Dublin Society would
accommodate them with the use of their Laboratory for that purpose,
all the members of the Dublin Society having free admission to such
lectures--
The following Resolutions were passed by the Dublin Society:--
"That in the event of Mr. Davy coming over to Ireland, and
consenting to deliver the Course referred to, the Farming Society
shall be accommodated with the use of the Laboratory, according to
their request.
"That it be referred to the Committee of Economy to consider on
what terms, and under what regulations, it may be expedient to
issue tickets of admission to the Electro-chemical Course, so as to
reimburse to the Society the expenses attendant on the arrangement;
and that, in order to give the fullest effect to such regulations,
the members of the Society renounce any claim to gratuitous
admission to this course."
A letter having been addressed to Mr. Davy by the Secretary of the
Society, inviting him to Dublin, for the purpose of delivering
courses of lectures, in conformity with the foregoing resolutions,
the following answer was received from him:--
TO JOHN LESLIE FOSTER, ESQ. M. P. SECRETARY TO THE DUBLIN SOCIETY.
May 30, 1810.
SIR,
I had the honour of communicating your letter to the President
and Council of the Royal Society, who have desired me to express
to you, Sir, and through you, to the Dublin Society, the lively
interest they feel in the prosperity of that useful public body,
and the desire that they have to promote its important object.
On these grounds, they have been pleased to permit me to be absent
from the meetings of the Royal Society, during the period that may
be necessary for delivering a Course of Lectures at the Laboratory
of the Dublin Society, in the month of November next.
Be pleased to express to the Dublin Society my grateful
acknowledgments for the honour they have done me in making such a
proposition; and assure them that I shall use my best exertions
to promote their views for the extension of Chemical Science, and
every other species of useful knowledge.
I beg to be permitted to thank you, Sir, for the flattering manner
in which you had the goodness to convey to me their proposal.
I am, Sir, with great respect,
Your obliged and obedient servant,
H. DAVY, SEC. R. S.
On the commencement of the Course, on the 8th of November 1810,
three hundred and seventy-one admission tickets had been issued;
and the Committee of Chemistry having expressed their opinion to
the Society, that the lecture-room would not afford accommodation
for a greater number of persons, the Assistant Secretary was
directed to limit his tickets to that number. On the 15th instant,
however, the number was increased to four hundred, without
inconvenience.
At the close of the Course, on the 29th of November, the Dublin
Society passed the following Resolutions:--
"Resolved, That the thanks of the Society be communicated to
Mr. Davy for the excellent Course of Lectures which, at their
request, has been delivered by him in their Laboratory; and to
assure him that the views which led the Society to seek for these
communications, have been answered even beyond their hopes;--that
the manner in which he has unfolded his discoveries has not merely
imparted new and valuable information, but further appears to
have given a direction of the public mind towards Chemical and
Philosophical enquiries, which cannot fail in its consequences to
produce the improvement of the Sciences, Arts, and Manufactures in
Ireland.
"That the thanks of the Society be communicated to the Royal
Society for their ready compliance with our request, in dispensing
with the engagements of Mr. Davy, during the last six weeks.
"That Mr. Davy be requested to accept the sum of five hundred
guineas from the Society."[96]
[96] There were four hundred tickets issued for the Course, sixty
of which were honorary; the produce of the remainder amounted to
672_l._ 5_s._ 3_d._ Davy received 525_l._; and the surplus went
to officers and servants, and for the discharge of incidental
expenses.
The following letter appears, from the date, to have been written
about a week before his arrival in Dublin.
TO THOMAS POOLE, ESQ.
October 12, 1810.
MY DEAR POOLE,
Upon every occasion your recommendation, or opinion, would have
great weight with me.
Amongst the candidates for the office of Clerk to the Royal
Society, there is one Mr. W----, that I am well acquainted with,
and who was formerly attached to the Royal Institution. He appears
to me, as well from his scientific character, as from his habits
and pursuits, to be admirably fitted for the situation. I advised
him nearly two months ago, in consequence of a conversation with
Sir Joseph Banks, to offer himself for the situation. I cannot
therefore interest myself for any other person who does not possess
superior qualifications.
Sir Joseph's maxim, which I hope will be adopted by all the
members, is--"let it be given to the most worthy." I have no doubt
that Mr.---- would fill the situation with credit, and that he
is a very worthy man; but, from all that I can learn, his claims
are much inferior to those of W----. We want not merely a civil,
gentlemanlike, honest man, but a man a little accustomed to
calculation, to astronomical observation, and to experiment.
I am in a delightful country here--the Valley of the Tyne--enjoying
a few days' leisure after a rather hard chemical campaign, and
preparing health and spirits for another in Ireland, where I am
going next week.
I hope to be in London by the first week in December. I intend next
summer to go into Cornwall--God willing; and I will not go through
without seeing you, and telling you that, under all circumstances,
I shall always think of you with the warmest esteem, and shall
always be
Your sincere friend,
H. DAVY.
In the following year, Davy was again solicited by the Dublin
Society to deliver lectures in their laboratory; and at a meeting
of the members on the 13th of June 1811, a series of resolutions
were passed, by which he was empowered to procure copies of many
of the geological sketches referred to in a course of lectures he
had delivered on Geology at the Royal Institution; and also to
superintend the construction of a large Voltaic battery, for the
illustration of the proposed lectures.
In compliance with this request, Davy delivered two distinct
courses; one on the Elements of Chemical Philosophy, the other on
Geology, for which he received the unanimous thanks of the Society,
and as a more substantial testimony of their gratitude, the sum[97]
of seven hundred and fifty pounds; the receipt of which Davy
acknowledged by the following letter.
[97] These Courses were more numerously attended than those in
1810, there having been issued about five hundred and twenty-five
tickets; the proceeds of which were 1101_l._ 2_s._
TO B. MAC CARTHY, ESQ. ASSISTANT SECRETARY TO THE DUBLIN SOCIETY.
Dublin, December 9, 1811.
SIR,
I have received your letter, inclosing a draught for seven hundred
and fifty pounds Irish.
I am very much gratified by the thanks of the Dublin Society, for
the courses of lectures which I had the honour of delivering in
their laboratory; and I am proud of their opinion, that they will
be useful to the Irish public.
The attention, candour, and indulgence with which they were
received by the audience, I shall remember with the warmest
feelings of gratitude as long as I live.
I have the honour to be, Sir, with much esteem, your obliged and
obedient servant,
H. DAVY.
Before he quitted Dublin, the Provost and Fellows of Trinity
College conferred upon him the honorary degree of LL.D., as an
expression of the high admiration which his eminent scientific
merits had so universally commanded.
In the month of August, in the same year, his opinion was requested
by a committee, as to the best method to be adopted for ventilating
the House of Lords; to which circumstance he alludes in the
following note to his friend Mr. Pepys.
August 10, 1811.
MY DEAR PEPYS,
I find that I am engaged on Wednesday, to meet Lord Liverpool, at
the House of Lords, to consider a mode of ventilating it.
This business, most unluckily, will prevent my accompanying you;
but I shall be glad to go with you on some other day, and to touch
up the trout at Cheynies, and afterwards to proceed to Serge Hill.
Very affectionately yours,
H. DAVY.
This undertaking, it must be allowed, was on Davy's part a most
complete failure: whether he had miscalculated the diameter and
number of the apertures necessary for establishing a current, it
is difficult to say, but it was obvious that the stream of fresh
air thus introduced was by no means adequate to the demand for
it.[98]
[98] In February 1812, he exhibited a model, in one of his
lectures at the Royal Institution, in illustration of his plan;
from which it appeared that the air deteriorated by respiration
was conducted through three copper pipes, terminating in a single
tube, to the roof of the building; and by means of ventilators
below, there was a constant supply of fresh air, the circulation
of which was promoted by a furnace.
The failure, so vexatious to Davy, became to others a fertile
source of pleasantry, and numerous epigrams, not exactly of a
character to meet the public eye, were very generally circulated,
and which, in recording the miscarriage of science, displayed the
triumph of wit.
The scientific renown of Davy having attracted the attention of
his late Majesty, at that time Prince Regent, he received from his
Royal Highness the honour of Knighthood, at a levee held at Carlton
House, on Wednesday, the 8th of April 1812; and it may be remarked,
that he was the first person on whom that honour had been conferred
by the Regent.
On the day following this occurrence, Sir Humphry delivered his
farewell lecture before the members of the Royal Institution;
for he was on the eve of assuming a new station in society,
which induced him to retire from those public situations which
he had long held with so much advantage to the world, and with
so much honour to himself. How far such a measure was calculated
to increase his happiness I shall not enquire; but I am bound to
observe, that it was not connected with any desire to abandon the
pursuit of science, nor even to relax in his accustomed exertions
to promote its interests. It was evident, however, to his friends,
that other views of ambition than those presented by achievements
in science, had opened upon his mind: the wealth he was about to
command might extend the sphere of his usefulness, and exalt him
in the scale of society: his feelings became more aristocratic, he
discovered charms in rank which had before escaped him, and he no
longer viewed Patrician distinction with philosophic indifference.
On the 11th of April 1812, Sir Humphry married Mrs. Apreece, the
widow of Shuckburgh Ashby Apreece, Esq. eldest son of Sir Thomas
Apreece: this lady was the daughter and heiress of Charles Kerr, of
Kelso, Esq. and possessed a very considerable fortune.
Immediately after the celebration of the marriage, Sir Humphry and
his bride proceeded to the hospitable mansion of Sir John Sebright,
and afterwards made a tour through Scotland, receiving wherever
they went the most flattering marks of attention.
During their excursion, Davy wrote various letters to his
scientific friends, several of which I shall introduce; but,
in order that those to Mr. Children may be understood, it will
be necessary that the reader should be made acquainted with a
transaction which occurred in the year 1811.
In consequence of some conversation on gunpowder, during which
Davy observed that its composition might be greatly improved
by rendering it less _hygrometric_, a proposition was started,
that he should join Mr. Children and Mr. Burton in establishing
a manufactory for its preparation upon chemical principles.
Whether Davy considered himself, in the strict commercial sense,
a partner, or merely a chemical adviser, it is perhaps not easy
to determine; but it is quite clear that both Mr. Children and
Mr. Burton considered him in the former light, although it is an
act of justice to those gentlemen to state, that the very moment
Davy expressed his disinclination to such an arrangement, they
immediately, without the slightest hesitation, released him from
all responsibility. This I am enabled to assert, after a most
careful investigation of all the correspondence that passed upon
the occasion.
TO JOHN GEORGE CHILDREN, ESQ.
Harewood House, July 14, 1812.
MY DEAR FRIEND,
I am very sorry that I missed you the day before I set out on my
journey. You will have learnt from your solicitor that I signed the
articles. I still think I shall return before any powder will be
made, at least if you do not make it till December, for our present
intention is to be in town early in that month.
I sent to you an imperfect copy of my book,[99] in which there were
no engravings, and in which one cancel was not inserted, thinking
that you would prefer a copy sent in that way: the cancelled
leaf, which you have not, contains a correction for the quantity
of nitrous acid gas and water to form the crystalline compound,
which is the base of oil of vitriol. Three parts nitrous acid gas
condense four parts sulphurous gas.
I have my little apparatus, which will enable me to pursue my
experiments on gunpowder. There is one conclusion very obvious
resulting from the new facts,--a _perfect_ gunpowder ought to
contain no more charcoal than is necessary to convert the oxygen of
the nitre into carbonic acid. Sulphur forms from nitre just as much
elastic fluid as charcoal, _i. e._ if similar quantities of nitre
be entirely decomposed, one by charcoal, and one by sulphur, and
if the sulphurous gas and the carbonic acid gas be compared, their
volumes will be equal. The advantage of forming carbonic acid gas
is, that it is more readily disengaged from the alkali. Now it is a
question, whether sulphur will decompose _sulphate_ of potash,--it
will decompose the carbonate; of this we are sure.
There ought, then, to be just as much sulphur as will form
sulphuret of potash with the potash: 191 of nitre, 28·5 of
charcoal, and 30 of sulphur, are the true proportions for forming
nothing but sulphuret of potash and elastic matter.
Pray send me some cards to circulate; address to me, Post Office,
Edinburgh. I hope you got Cavendish's balance.
I have been here for two days:--it is a very magnificent place:
good fishing for pike, trout, and grayling. Lady D. desires her
kind remembrances.
I am, my dear friend,
Most affectionately yours,
H. DAVY.
[99] "Elements of Chemical Philosophy," to be presently noticed.
TO THE SAME.
Dunrobin Castle, near Golspie, August 21.
MY DEAR FRIEND,
I hope you are making progress in our manufactory. I shall expect,
on my return, to find your powder the best and strongest, and to
make trial of it. I wish I had some of it here, the black-cock and
grouse would feel its efficacy. I have been expecting a letter from
you every day.
This house is so delightful, the scenery so grand, and the
field-sports so perfect, that I think we shall not quit it for a
fortnight.
I went to Inverness and fished for salmon. I also went to two or
three other places, but not one did I catch till I arrived here.
The first day I landed seven noble ones, and played three more in
four or five hours. The next day I played eight and landed three,
besides white trout in abundance.
I have shot only one day, for a few hours; but we found grouse
at every fifty yards, and I shot seven. We are just going to try
sea-fishing.
Pray write to me a little news of what is doing for science and the
world.
I beg you will remember me most kindly to your father and to Dr.
Babington, and Brande, when you see them.
I am, my dear friend,
Most affectionately yours,
H. DAVY.
TO WILLIAM CLAYFIELD, ESQ.
Dunrobin, near Golspie, August 28, 1812.
DEAR CLAYFIELD,
I am much obliged to you for two very kind letters, and for a box
containing specimens from St. Vincent.[100] I beg you will thank
the gentleman who was so good as to cause them to be collected for
me. The box followed me to Inverness.
The ashes, I think, are likely to fertilize Barbadoes. There is
a parallel case of materials having been carried so far in the
eruption in Iceland in 1783.
I have been with my wife making a tour through the North since the
beginning of July. We have arrived at our extreme point, and shall
slowly proceed South in about a fortnight.
I wish you could be of our party here; we are in a delightful
house, that of Lord Stafford, in a country abounding with fish and
game. I have caught about thirty salmon since I have been here, and
killed grouse, wild ducks, teal, &c. I have not yet shot a stag,
but I hope to do so this next week.
I have just published a volume of the Elements of Chemistry, and I
hope to publish another in the course of the Spring.
Having given up lecturing, I shall be able to devote my whole time
to the pursuit of discovery.
I have not sent you a copy of my book, for I have thought that the
best mode of avoiding giving offence to some, was by not making
presents at all. Had I not so determined, one of the first copies
would have been sent to you, as a mark of the warm esteem and
regard of
Your affectionate friend,
H. DAVY.
[100] Specimens of substances ejected from the crater in that
island, which Mr. Clayfield forwarded to Davy, in consequence
of having heard that he had been engaged in examining the sand
collected at Barbadoes, and which was a product of the same
eruption.
TO SAMUEL PURKIS, ESQ.
Dunrobin Castle, Aug. 29, 1812.
MY DEAR PURKIS,
You may probably be surprised to receive a letter from me from this
remote corner of the North; but I owe you a letter, and I have a
great inclination, wherever I may be, to discharge all debts, and
particularly those rendered due by kindness.
Receive my warm acknowledgments for your kind congratulations on my
becoming a Benedick. I can now speak from experience, in which you
have long participated. I am convinced that the natural state of
domestic society is the best fitted for man, whether he be devoted
to philosophy, or to active life.
I shall have much pleasure in presenting my wife to you and to Mrs.
Purkis, on my return.
We have had a delightful tour through the Highlands. We are at
the extreme point of our journey. The pleasures of a refined
society--that of Lord and Lady Stafford's family--have induced
us to make a long pause here. We think we shall be in London the
beginning of December.
I have spent some days such as we passed together in Wales. We have
had all the varieties of river, mountain, and wood scenery. The
Lakes of Scotland are infinitely finer than those of Wales; but
the glens of the Principality may fairly stand in competition with
those of the Highlands.
I hope I shall find you and your family in good health, and that
you will have spent a very pleasant summer. I am, my dear Purkis,
Very sincerely and affectionately yours,
H. DAVY.
TO JOHN GEORGE CHILDREN, ESQ.
Dunkeld, Sept. 27, 1812.
MY DEAR FRIEND,
I have received your two kind letters. I hope your quiet life, and
reasonable medical discipline, will entirely restore your health.
We are now on our return, and probably shall arrive in London
before the middle of November: our time, however, is uncertain, as
the Election may hasten, or keep us back for want of horses.
I can do nothing respecting the licence till my return; I will
then see Mr. Wharton, or Mr. Vansittart. I have another subject
of conversation in which they are interested, and I can easily
introduce that of gunpowder.
I have been tolerably successful as a shot lately. I have not
fished. My last adventure was at the Spey, near Gordon Castle,
where I killed some noble salmon. At Blair Athol I shot some
ptarmigans and a stag. I am now at Dunkeld, which I think the most
beautiful habitable spot in the Highlands. The Tay, a noble river,
rolls with a majestic stream through lofty woods seated upon cliffs
and rounded hills; and in the background are the Mountains of
Benyglor and the hills of Killycrankie.
My wife desires her kind remembrances. Pray offer mine to
your father and daughter, and believe me to be always most
affectionately yours,
H. DAVY.
TO THE SAME.
Edinburgh, October 14.
MY DEAR FRIEND,
We are on our return: I am well, but I am sorry to say that Lady D.
is very much indisposed, and anxiety for her hastens my journey to
town.
* * * * *
I have received a very interesting letter from Ampère. He says
that a combination of chlorine and azote has been discovered at
Paris, which is a fluid, and explodes by the heat of the hand; the
discovery of which cost an eye and a finger to the author. He gives
no details as to the mode of combining them. I have tried in my
little apparatus with ammonia cooled very low, and chlorine, but
without success.
There is little doing here ... dresses and dances. Sir James Hall
is writing on a sort of Deluge. Playfair is the true and amiable
Philosopher. My brother is making experiments on animal matter.
I hope your gunpowder works are nearly finished. I shall be at the
opening ball. As soon as I return I shall give my mind up to this
matter. My wife desires her kind remembrances. Mine to your worthy
father and Anna.
God bless you, my dear friend, and believe me
Ever affectionately yours,
H. DAVY.
On his return to town, after this tour, the following letter was
addressed to his friend at Tonbridge:--
October 24, 1812.
MY DEAR CHILDREN,
I have just seen Pepys, and rejoice that he gives me so good an
account of your health. My wife is much better, except that she
has a swollen foot. I have never seen her in such good health and
spirits. She is resolved to lead a home life of perfect quiet for
six weeks, and I fear you will not be able to tempt her to quit her
fire-side, though there is no visit she would make with greater
pleasure: but lameness does not suit the country; and for one so
enthusiastically fond of nature, it would be vexatious to be in the
country, and not to be able to enjoy hills, and meads, and woods.
But I am ready to come to my business whenever you think I can be
useful. I shall set to work to make gunpowder with as much ardour
as Miles Peter--I hope with similar results.
I shall not be able to endure a very long separation from my wife,
but for three or four days I am at your command.
I have been working yesterday and to-day on some new objects; and
we are to have a meeting on Wednesday, at one o'clock, at the
Institution, to try to make this compound of azote and chlorine,
and to try some other experiments. Afterwards we (Angling Chemists)
propose a dinner at Brunet's. If you can come to town on that day,
I will promise to return with you.
God bless you, my dear Children, and believe me to be most
affectionately yours,
H. DAVY.