By comparing the writings as well as the discoveries of these two

great philosophers, we shall readily perceive the intellectual

distinctions I have endeavoured to establish. "From their fruits

shall ye know them." The discoveries of Davy were the results of

extensive views and new analogies; those of Wollaston were derived

from a more exact examination of minute and, to ordinary observers,

scarcely appreciable differences. This is happily illustrated by a

comparison of the means by which each discovered new metals. The

alkaline bases were the products of a comprehensive investigation,

which had developed a new order of principles; the detection of

palladium and rhodium among the ores of platinum, was the reward

of delicate manipulation, and microscopic scrutiny. As chemical

operators, I have already pointed out their striking peculiarities,

and they will be found to be in strict keeping with the other

features of their respective characters. I might extend the

parallel farther; but Dr. Henry, in the eleventh edition of his

"System of Chemistry," has delineated the intellectual portraits of

these two philosophers with so masterly a hand, that by quoting the

passage, all farther observation will be rendered unnecessary.

"To those high gifts of nature, which are the characteristics of

genius, and which constitute its very essence, both those eminent

men united an unwearied industry and zeal in research, and habits

of accurate reasoning, without which even the energies of genius

are inadequate to the achievement of great scientific designs.

With these excellencies, common to both, they were nevertheless

distinguishable by marked intellectual peculiarities. Bold,

ardent, and enthusiastic, Davy soared to greater heights; he

commanded a wider horizon; and his keen vision penetrated to its

utmost boundaries. His imagination, in the highest degree fertile

and inventive, took a rapid and extensive range in pursuit of

conjectural analogies, which he submitted to close and patient

comparison with known facts, and tried by an appeal to ingenious

and conclusive experiments. He was imbued with the spirit, and

was a master in the practice, of the inductive logic; and he has

left us some of the noblest examples of the efficacy of that

great instrument of human reason in the discovery of truth. He

applied it, not only to connect classes of facts of more limited

extent and importance, but to develope great and comprehensive

laws, which embrace phenomena that are almost universal to the

natural world. In explaining those laws, he cast upon them the

illumination of his own clear and vivid conceptions;--he felt an

intense admiration of the beauty, order, and harmony, which are

conspicuous in the perfect Chemistry of Nature;--and he expressed

those feelings with a force of eloquence which could issue only

from a mind of the highest powers and of the finest sensibilities.

With much less enthusiasm from temperament, Dr. Wollaston was

endowed with bodily senses[125] of extraordinary acuteness and

accuracy, and with great general vigour of understanding. Trained

in the discipline of the exact sciences, he had acquired a powerful

command over his attention, and had habituated himself to the

most rigid correctness, both of thought and of language. He was

sufficiently provided with the resources of the mathematics, to be

enabled to pursue with success profound enquiries in mechanical and

optical philosophy, the results of which enabled him to unfold the

causes of phenomena not before understood, and to enrich the arts

connected with those sciences, by the invention of ingenious and

valuable instruments. In Chemistry, he was distinguished by the

extreme nicety and delicacy of his observations; by the quickness

and precision with which he marked resemblances and discriminated

differences; the sagacity with which he devised experiments and

anticipated their results; and the skill with which he executed

the analysis of fragments of new substances, often so minute as

to be scarcely perceptible by ordinary eyes. He was remarkable,

too, for the caution with which he advanced from facts to general

conclusions: a caution which, if it sometimes prevented him from

reaching at once to the most sublime truths, yet rendered every

step of his ascent a secure station, from which it was easy to rise

to higher and more enlarged inductions. Thus these illustrious men,

though differing essentially in their natural powers and acquired

habits, and moving, independently of each other, in different

paths, contributed to accomplish the same great ends--the evolving

new elements; the combining matter into new forms; the increase of

human happiness by the improvement of the arts of civilized life;

and the establishment of general laws, that will serve to guide

other philosophers onwards, through vast and unexplored regions of

scientific discovery."

[125] Mr. Babbage considers it as a great mistake to suppose

that Dr. Wollaston's microscopic accuracy depended upon the

extraordinary acuteness of the bodily senses; a circumstance,

he says, which, if it were true, would add but little to his

philosophical character. He is inclined to view it in a far

different light, and to see in it one of the natural results of

the precision of his knowledge and of the admirable training of

his intellectual faculties.

* * * * *

My history draws towards a conclusion.--Sir Humphry Davy, during

the latter days of his life, was cheered by the society and

affectionate attentions of his godson, the son of his old friend

Mr. James Tobin.[126] He had been the companion of his travels, and

he was the solace of his declining hours.

[126] This inestimable man died on his plantation at Nevis, on

the 19th of October 1814, in the forty-eighth year of his age.

He had been resident for some months at Rome, where he occupied

the second floor of a house in Via di Pietra, a street that leads

out of the Corso. During this period, he declined receiving any

visitors, and had constantly some one by his side reading light

works of interest to him, an amusement which was even continued

during his meals.

As soon as the account of Sir Humphry having sustained another

paralytic seizure was communicated to Lady Davy, who was in

London at the time, she immediately set off, and so rapidly was

her journey performed, that she reached Rome in little more than

twelve days. Dr. John Davy, also, hastened from Malta, on receiving

intelligence of his brother's imminent danger.

During his slow and partial recovery from this seizure, he

learnt the circumstance of his name having been introduced into

parliamentary proceedings, in the following manner. On the 26th

of March 1829, on presenting a petition in favour of the Catholic

claims from a very great and most respectable meeting at Edinburgh,

Sir James Mackintosh, after having mentioned the name of Sir

Walter Scott as being at the head of the petitioners, continued

thus:--"Although not pertinent to this petition, yet connected

with the cause, I indulge in the melancholy pleasure of adding to

the first name in British literature the first name in British

science--that of Sir Humphry Davy. Though on a sick-bed at Rome, he

was not so absorbed by his sufferings as not to feel and express

the glow of joy that shot across his heart at the glad tidings of

the introduction of a bill which he hailed as alike honourable to

his religion and his country."

I am assured that the last mark of satisfaction which he evinced

from any intelligence communicated to him was on reading the

above passage. He showed a pleasure unusual in his state of

languor at the justice thus done, in the face of his country, to

his consistency, to his zeal for religion and liberty, and to the

generous sentiments which cheered his debility. The marks of his

pleasure were observed by those who were brought most near to him

by the performance of every kind office.

Although there appeared some faint indications of reviving power,

his most sanguine friends scarcely ventured to indulge a hope

that his life would be much longer protracted. Nor did he himself

expect it. The expressions in his Will (printed in an Appendix)

sufficiently testify the opinion he had for some time entertained

of the hopelessness of his case.

In addition to this Will, he left a paper of directions, which have

been religiously observed by his widow. He desires, for instance,

that the interest arising from a hundred pounds stock may be

annually paid to the Master of the Penzance Grammar School, on

condition that the boys may have a holiday on his birthday.[127]

There is something singularly interesting in this favourable

recollection of his native town, and of the associations of his

early youth. It adds one more example to show that, whatever may

have been our destinies, and however fortune may have changed our

conditions, where the heart remains uncorrupted, we shall, as the

world closes upon us, fix our imaginations upon the simplicities of

our youth, and be cheered and warmed by the remembrance of early

pleasures, hallowed by feelings of regard for the memory of those

who have long since slept in the grave.

[127] I understand that the present Master, the Reverend Mr.

Morris, has expressed his intention to apply the above sum to

purchasing a medal, which he intends to bestow as a Prize to the

most meritorious scholar.

With that restlessness which characterises the disease under

which Sir Humphry Davy suffered, he became extremely desirous of

quitting Rome, and of establishing himself at Geneva. His friends

were naturally anxious to gratify every wish; and Lady Davy kindly

preceded him on the journey, in order that she might at each stage

make arrangements for his comfortable reception. Apartments were

prepared for him at _L'Hotel de la Couronne_, in the Rue du Rhone;

and at three o'clock on the 28th of May, having slept the preceding

evening at Chambery, he arrived at Geneva, accompanied by his

brother, Mr. Tobin, and his servant.

At four o'clock he dined, ate heartily, was unusually cheerful,

and joked with the waiter about the cookery of the fish, which he

appeared particularly to admire; and he desired that, as long as

he remained at the hotel, he might be daily supplied with every

possible variety that the lake afforded. He drank tea at eleven,

and having directed that the feather-bed should be removed, retired

to rest at twelve.

His servant, who slept in a bed parallel to his own, in the same

alcove, was however very shortly called to attend him, and he

desired that his brother might be summoned. I am informed that,

on Dr. Davy's entering the room, he said, "I am dying," or words

to that effect; "and when it is all over, I desire that no

disturbance of any kind may be made in the house; lock the door,

and let every one retire quietly to his apartment." He expired at a

quarter before three o'clock, without a struggle.

On the following morning, his friends Sismondi[128] and De Candolle

were sent for; and the Syndics, as soon as the circumstance of

his death was communicated to them, gave directions for a public

funeral on the Monday; at which the magistrates, the professors,

the English residents at Geneva, and such inhabitants as desired

it, were invited to attend. The ceremony was ordered to be

conducted after the custom of Geneva, which is always on foot--no

hearse; nor did a single carriage attend. The cemetery is at

Plain-Palais, some little distance out of the walls of the town.

The Couronne being at the opposite extremity, the procession was

long.

[128] Simond de Sismondi, the celebrated author of the History of

the Italian Republic.

The following was the order of the procession:--[129]

[129] For these particulars I am indebted to Sir Egerton Brydges.

The Two Syndics, (_in their robes_) { M. MASTOW,

{ M. GALLATIN.

Magistrates of the Republic, { M. FAZIO,

{ M. SALLADIN.

Professors of the College, in their robes,

MM. Simond de Sismondi--A. de Candolle.

THE ENGLISH.

Lord EGLINGTON,

Lord TWEDELL,

Right Hon. WM. WYCKHAM,

Capt. ARCHIBALD HAMILTON,

Mr. CAMPBELL,

Mr. FRANKS,

WM. HAMILTON, Esq., Ex-Ambassador at Naples.

Sir EGERTON BRYDGES, Bart.

Colonel ALCOCK,

Captain SWINTERS,

Mr. ALCOCK,

Mr. DREW,

Mr. HEYWOOD,

Mr. SITWELL,

&c.

The Students of the College.

The Citizens of Geneva.

The English service was performed by the Rev. John Magers, of

Queen's College, and the Rev. Mr. Burgess.

The grave was stated in the public prints to be next to that of his

friend the late Professor M. A. Pictet: this is not the fact. It is

far away from it, on the second line of No. 29, the fourth grave

from the end of the west side of the Cemetery.

* * * * *

Sir Humphry Davy having died without issue, his baronetcy has

become extinct.

At present, the only memorial raised to commemorate the name of

this distinguished philosopher is a Tablet placed in Westminster

Abbey by his widow. It is thus inscribed:--

TO THE MEMORY OF

SIR HUMPHRY DAVY, BARONET;

DISTINGUISHED THROUGHOUT THE WORLD

BY HIS

DISCOVERIES IN CHEMICAL SCIENCE.

PRESIDENT OF THE ROYAL SOCIETY;

MEMBER OF THE NATIONAL INSTITUTE OF FRANCE.

BORN 17 DECEMBER 1778, AT PENZANCE.

DIED 28 MAY 1829, AT GENEVA,

WHERE HIS REMAINS ARE INTERRED.

The numerous scientific societies of which he was a member, will,

no doubt, consecrate his memory. An eloquent Eloge has been read

by Baron Cuvier before the Institute of France; but it has not

yet been published: I have obtained, however, a copy of a speech

delivered upon the same occasion, by H. C. Van der Boon Mesch,

before the Institute of the Netherlands.

Mr. Davies Gilbert, his early friend and patron, has likewise paid

to his memory a just and appropriate testimony of respect and

admiration, in an address from the chair of the Royal Society.

The inhabitants of Penzance and its neighbourhood, animated by

feelings of honourable pride and strong local attachment, will

shortly, it is understood, raise a pyramid of massive granite to

his memory, on one of those elevated spots of silence and solitude,

where he delighted in his boyish days to commune with the elements,

and where the Spirit of Nature moulded his genius in one of her

wildest moods.

As yet, no intention on the part of the Government to commemorate

this great philosopher, by the erection of a national monument,

has been manifested: for the credit, however, of an age which is

so continually distinguished as the most enlightened period in our

history, I do hope the disgrace of such an omission may pass from

us; although, I confess, it is rather to be wished than expected,

when it is remembered that not a niche has been graced by the

statue of Watt, while the giant iron children of his inventive

genius are serving mankind in every quarter of the civilized world.

A very erroneous impression would seem to exist with regard to the

object and importance of such monuments. They are not to honour

the dead, but to improve the living; not to give lustre to the

philosopher, but to afford a salutary incentive to the disciple;

not to perpetuate discoveries, for they can never be lost; but

to animate scientific genius, and to engage it upon objects that

may be useful to the commonwealth. Let it be remembered, that

the ardour of the Roman youth was kindled into active emulation,

whenever they beheld the images of their ancestors.

"Nam sæpe audivi, Q. Maximum, P. Scipionem, præterea civitatis

nostræ præclaros viros, solitos ita dicere, cùm majorum imagines

intuerentur, vehementissimè sibi animum ad virtutem accendi.

Scilicet non ceram illam, neque figuram tantam vim in sese habere;

sed memoriâ rerum gestarum eam flammam egregiis viris in pectore

crescere, neque prius sedari, quàm virtus eorum famam atque gloriam

adæquaverit."[130]

[130] Sallust. Bell. Jugurth.

The fame of such a philosopher as Davy can never be exalted by any

frail memorial which man can raise. His monument is in the great

Temple of Nature.[131] His chroniclers are Time and the Elements.

The destructive agents which reduce to dust the storied urn, the

marble statue, and the towering pyramid, were the ministers of his

power, and their work of decomposition is a perpetual memorial of

his intelligence.

[131] [Greek: Andrôn gar epiphanôn pasa gê taphos, kai ou

stêlôn monon en tê oikeia sêmainei epigraphê, alla kai en tê mê

prosêkousê agraphos mnêmê par' hekastô tês gnômês mallon ê tou

ergou endiaitatai.--Thucydides, B. 43.]

A SKETCH OF THE HISTORY OF CHEMICAL SCIENCE, WITH A VIEW TO EXHIBIT

THE REVOLUTIONS PRODUCED IN ITS DOCTRINES BY THE DISCOVERIES OF SIR

HUMPHRY DAVY.

The rapidity with which chemical opinions have risen into

notice, flourished for a while, and then fallen into disrepute,

to be succeeded by others equally precarious in their tenure

and ephemeral in their popularity, are circumstances which the

superficial reasoner has ever deplored, and the Sciolist as

constantly converted into arguments against the soundness of the

science which produced them. The leaves of a season will sprout,

expand, and wither; and the dry foliage will be pushed off by

the propulsion of new buds; but this last change is not effected

in them, until they have absorbed the light and dews of heaven

for the nourishment of the plant that bore them; and when even

they shall have fallen to the earth, they will farther supply its

spreading roots with fresh soil for its future growth and healthy

developement; and entering into new combinations, will re-appear in

the same tree under fresh forms of usefulness and symmetry. In like

manner, chemical theories are but for a season; they are nothing

more than general expressions of known facts; they may delight by

their ingenuity, as vegetable forms captivate by their beauty, but

their real and substantial use is to extend science; and as facts

accumulate under their operation, they must give way to others

better adapted to the increased growth and expansion of knowledge;

nor does the utility of theories cease with their rejection,--they

afford objects of analogy and comparison which assist the

philosopher in his progress to truth, while their elements furnish

materials for future arrangements. Were it otherwise, we should

behold science in its advancement as a shapeless mass, enlarging by

constant appositions, but without a single sign of growth or inward

sympathy.

If chemical theories have undergone more rapid and frequent

changes than those of other branches, the circumstance has arisen

from the rapid manner in which new and important facts have been

successively added to the general store.

Whatever may be the vices attributed to Chemistry on such

occasions, they have belonged to the philosophers engaged in its

pursuit, and are no evidence of the frailty of the science itself;

and here it must be admitted, that there exists in one portion of

mankind a self-love which cannot patiently submit to a change of

opinions of which they are either the authors or defenders, while

in another there predominates a timidity which naturally leads

them, amidst the storm of controversy, to cling to the wreck of

a shattered theory, rather than to trust themselves to a new and

untried bark.

In our review of the history of Science, we have frequently to

witness how the wisest philosopher has strained truth, for the

support of a favourite doctrine, and measured and accommodated

facts to theory, instead of adapting theories to facts--but this

vice does not belong exclusively to chemical philosophers. Huygens,

the celebrated Dutch Astronomer, from some imaginary property

in the number _six_, having discovered _one_ of Saturn's moons,

absolutely declined looking for any more, merely because that one,

when added to the four moons of Jupiter, and to the one belonging

to the Earth, made up the required number.

Such reflections naturally arise on viewing, with a philosophic

eye, the progress and modifications of chemical opinions; and

it is essential that they should be duly appreciated upon the

present occasion; for, before any just estimate can be formed of

the talents and services of Sir Humphry Davy, we must thoroughly

consider, in all their bearings and relations, the various

prejudices with which he had to contend in his efforts to modify

a gigantic theory, which enjoyed an unrestrained dominion in the

chemical world, and for many years continued to be the pride of

France and the admiration of Europe.

It would be quite foreign to the plan of this sketch,[132] which

the reader must consider as wholly subservient to the object that

has been announced, to enquire how far the ancients, in their

metallurgical processes, can be said to have exercised the arts

of chemistry. Equally vain would it be to enter into a history of

that system of delusion and imposture, so long practised under the

denomination of Alchymy. It is only necessary to consider Chemistry

in its dignified and purely scientific form; and we have only to

notice those commanding discoveries and opinions which led to the

developement of that system, which the genius of Davy was destined

to modify.

[132] This historical sketch has no pretensions to originality.

It is compiled from the best authors, and from the Introduction

to Sir H. Davy's Elements of Chemical Philosophy.

The origin of Chemistry, as a science, cannot be dated farther

back than about the middle of the seventeenth century; and

Beccher, the contemporary of Boyle, who was born at Spires in

1635, was unquestionably the first to construct any thing like a

general theory. He formed the bold idea of explaining the whole

system of the earth by the mutual agency and changes of a few

elements. And by supposing the existence of a vitrifiable, a

metallic, and an inflammable earth, he attempted to account for

the various productions of rocks, crystalline bodies, and metallic

veins, assuming a continual interchange of principles between

the atmosphere, the ocean, and the solid surface of the globe,

and considering the operations of nature as all capable of being

imitated by art.

Albertus Magnus had advanced the opinion that the metals were

earthy substances impregnated with a certain inflammable principle;

but Beccher supported the idea of this principle not only as the

cause of metallization, but likewise of combustibility. Stahl,

however, one of the most extraordinary men that Germany ever

produced, having adopted and amplified this theory, carried off the

entire credit of being its founder, and it is universally spoken of

as the _Stahlian Theory_.

This theory forms so important a feature in the history of

chemistry, and so long maintained its ascendency in the schools,

that it will be necessary to give the reader a short summary of

its principles. It assumed that all _combustible_ bodies are

compounds: one of the constituents being volatile, and therefore

easily dissipated during the act of combustion; while the other,

being fixed, constantly remained as the residue of the process.

This volatile principle, for which Stahl invented the term

_Phlogiston_, was considered as being identical in every species

of combustible matter; in short, it was supposed that there was

but one principle of combustibility in nature, and that was the

imaginary phantom Phlogiston, which for nearly a century possessed

the schools of Europe, and, like an evil spirit, crossed the

path of the philosopher at every step, and by its treacherous

glare allured him from the steady pursuit of truth; for, whether

a substance were combustible or not, its nature could never be

investigated without a reference to its supposed relations with

Phlogiston; its presence, or its absence, was supposed to stamp a

character upon all bodies, and to occasion all the changes which

they undergo. Hence chemistry and combustion came to be in some

measure identified; and a theory of combustion was considered the

same thing as a theory of chemistry.

The identity of Phlogiston in all combustible bodies was founded

upon observations and experiments of so decisive a nature, that

after the existence of the principle itself was admitted, they

could not fail to be satisfactory. When phosphorus is made to

burn, it gives out a strong flame, much heat is evolved, and the

phosphorus is dissipated in fumes, which, if properly collected,

will quickly absorb moisture from the atmosphere, and produce

an acid liquid known by the name of phosphoric acid. Phosphorus

then must consist, say the Stahlians, of Phlogiston and this acid.

Again--If this liquid be evaporated to a dry substance, mixed with

a quantity of charcoal powder, and then heated in a vessel from

which the external air is excluded, a _portion_, or the _whole_ of

the charcoal will disappear, and phosphorus will be reproduced,

possessing all the properties that it had before it was subjected

to combustion. In this case, it was supposed that the charcoal

restored the phlogiston. There was much plausibility in all this,

as well as in the reasoning which followed. Since we may employ,

with equal success, any kind of combustible body for the purpose

of changing phosphoric acid into phosphorus, such as lamp-black,

sugar, resin, or even several of the metals, it was concluded that

all such bodies contain a common principle which they communicate

to the phosphoric acid; and since the new body formed is in all

cases identical, the principle communicated must also be identical.

Hence combustible bodies contain an identical principle, and this

principle is Phlogiston.

The same theory applied with equal force to the burning of sulphur

and several of the metals, and to their reconversion by combustible

bodies.

When lead is kept nearly at a red-heat in the open air for some

time, it is converted into a pigment called _red lead_; this is a

calx of lead. To restore this calx again to metallic lead, it is

only necessary to heat it in contact with almost any combustible

matter; all these bodies therefore must contain one common

principle, which they communicated to the red lead, and by so doing

reconverted it to the state of metal. Metals then were regarded

as compounds of _calces_ and phlogiston. Thus far the theory

works glibly enough; but now comes a startling fact, which was

long unnoticed by the blind adherents of Stahl, or, if noticed,

intentionally overlooked. It was observed very early, that when a

metal was converted into a calx, its weight was increased. When

this difficulty first forced itself upon the attention of the

Phlogistians, it was necessary that they should either explain it,

or at once abandon their theory. They accordingly endeavoured to

evade the difficulty, not only by asserting that phlogiston had no

weight, but that it was actually endowed with a principle of levity.

It was not possible, however, that any rational notions should

have been entertained upon the subject of combustion, at a

period when the composition of the atmosphere even was unknown.

Let us therefore follow the stream of discovery, skimming the

surface merely, as it flowed onward towards quite a new field of

science--Pneumatic Chemistry.

Boyle and Hooke, who had improved the air-pump invented by

Otto de Guericke, of Madenburgh, first used this apparatus for

investigating the properties of air; and they concluded from their

experiments that air was absolutely necessary to combustion and

respiration, and that one part of it only was employed in these

processes; and Hooke formed the sagacious conclusion, that this

principle is the same as the substance fixed in nitre, and that

combustion is a chemical process, the solution of the burning body

in elastic fluid, or its union with this matter.

Mayow, of Oxford, in 1674, published his treatises on the

Nitro-aërial spirit, in which he advanced opinions similar to those

of Boyle and Hooke, and supported them by a number of original and

curious experiments.

Dr. Hales, about 1724, resumed the investigations commenced with

so much success by Boyle, Hooke, and Mayow; and endeavoured to

ascertain the chemical relations of air to other substances, and

to ascertain by statistical experiments the cases in nature, in

which it is absorbed or emitted. He obtained a number of curious

and important results; he disengaged elastic fluids from various

substances, and drew the conclusion, that air was a chemical

element in many compound bodies, and that flame resulted from the

action and reaction of aërial and sulphurous particles; but all

his reasonings were contaminated with the notion of one elementary

principle constituting elastic matter, and modified in its

properties by the effluvia of solid or fluid bodies.

The light of Pneumatic science which had dawned under Hooke, Mayow,

and Hales, burst forth in splendour under the ascendency of that

constellation of British science, Black, Cavendish, and Priestley.

In 1756, Dr. Black published his researches on calcareous,

magnesian, and alkaline substances, by which he proved the

existence of a gaseous body, perfectly distinct from the air of

the atmosphere. He showed, that quick-lime differed from marble

and chalk by not containing this substance, which he proved to be

a weak acid, capable of being expelled from alkaline and earthy

bodies by stronger acids.

As nothing is more instructive than to enquire into the

circumstances which have led to a great discovery, I quote with

pleasure the following passage from Dr. Thomson's History of

Chemistry.

"It was the good fortune of chemical science that, at this time

(1751), the opinions of professors were divided concerning the

manner in which certain lithonthriptic medicines, particularly

lime-water, acted in alleviating the excruciating pains of the

stone and gravel. The students usually partake of such differences

of opinion: they are thereby animated to more serious study, and

science gains by their emulation.

"All the medicines which were then in vogue as solvents of calculi

had a greater or less resemblance to caustic potash or soda;

substances so acrid, when in a concentrated state, that in a short

time they reduce the fleshy parts of the animal body to a mere

pulp. They all seemed to derive their efficacy from quick-lime,

which again derived its power from the fire. It was therefore very

natural for them to ascribe its power to igneous matter imbibed

from the fire, retained by the lime, and communicated by it to

alkalies which it renders powerfully acrid. It appears from Dr.

Black's note-books, that he originally entertained the opinion,

that caustic alkalies acquired igneous matter from quick-lime. In

one of them, he hints at some way of catching this matter as it

escapes from lime, while it becomes mild by exposure to the air;

but on the opposite blank page is written, 'Nothing escapes--the

cup rises considerably by absorbing air.' A few pages further on,

he compares the loss of weight sustained by an ounce of chalk when

calcined, with its loss while dissolved in muriatic acid.

"These experiments laid open the whole mystery, as appears by

another memorandum. 'When I precipitate lime by a common alkali,

there is no effervescence: the air quits the alkali for the lime;

but it is lime no longer, but c. c. c: it now effervesces, which

good lime will not.'--What a multitude of important consequences

naturally flowed from this discovery! He now knew to what the

causticity of alkalies is owing, and how to induce it, or remove

it, at pleasure. The common notion was entirely reversed. Lime

imparts nothing to the alkalies; it only removes from them a

peculiar kind of air (_carbonic acid gas_) with which they were

combined, and which prevented their natural caustic properties

from being developed. All the former mysteries disappear, and the

greatest simplicity appears in those operations of nature which

before appeared so intricate and obscure."

Dr. Thomson afterwards observes,--"The discovery which Dr. Black

had made, that marble is a combination of lime and a peculiar

substance, to which he gave the name of _fixed air_, began

gradually to attract the attention of chemists in other parts of

the world. It was natural, in the first place, to examine the

nature and properties of this fixed air, and the circumstances

under which it is generated. It may seem strange and unaccountable

that Dr. Black did not enter with ardour into this new career

which he had himself opened, and that he allowed others to reap

the corn after having himself sown the grain. Yet he did take

some steps towards ascertaining the properties of _fixed air_;

though I am not certain what progress he made. He knew that a

candle would not burn in it, and that it is destructive to life,

when any living animal attempts to breathe it. He knew that it is

formed in the lungs during the breathing of animals, and that it

is generated during the fermentation of wine and beer. Whether

he was aware that it possesses the properties of an acid, I do

not know; though with the knowledge which he possessed that it

combines with alkalies and alkaline earths, and neutralizes them,

or at least blunts and diminishes their alkaline properties,

the conclusion that it partook of acid properties was scarcely

avoidable. All these, and probably some other properties of _fixed

air_, he was in the constant habit of stating in his lectures

from the very commencement of his academical career; though, as

he never published any thing on the subject himself, it is not

possible to know exactly how far his knowledge of the properties of

_fixed air_ extended. The oldest manuscript copy of his lectures

that I have seen was taken down in writing in the year 1773; and

before that time Mr. Cavendish had published his paper on _fixed

air_ and _hydrogen gas_, and had detailed the properties of each.

It was impossible from the manuscript of Dr. Black's lectures, to

know which of the properties of _fixed air_ stated by him were

discovered by himself, and which were taken from Mr. Cavendish."

An idea so novel and important as that of an air possessing

properties quite different from that of the atmosphere, existing in

a fixed and solid state in various bodies, was not received without

doubt, and even opposition. Several German enquirers endeavoured

to controvert it. Meyer attempted to show that limestone became

caustic, not by the emission of elastic matter, but by combining

with a peculiar substance in the fire; the loss of weight, however,

was wholly inconsistent with such a view of the question: and

Bergman at Upsal, Macbride in Ireland, Keir at Birmingham, and

Cavendish in London, fully demonstrated the truth of the opinion of

Black, and a few years were sufficient to establish his theory upon

an immutable foundation, and to open a new road to most important

discoveries.

The knowledge of one elastic fluid, entirely different in its

properties from air, very naturally suggested the probability of

the existence of others. The processes of fermentation which had

been observed by the ancient chemists, and those by which Hales

had disengaged and collected elastic substances, were now regarded

under a novel point of view; and the consequence was, that a number

of new bodies, possessed of very extraordinary properties, were

discovered.

Mr. Cavendish, about the year 1765, invented an apparatus for

examining elastic fluids confined by water, which has since been

called the _hydro-pneumatic_ apparatus. He discovered inflammable

air, and described its properties; he ascertained the relative

weights of fixed air, inflammable air, and common air, and made a

number of beautiful and accurate experiments on the properties of

these elastic substances.

Dr. Priestley, in 1771, entered the same path of enquiry; and

principally by repeating the processes of Hales, added a number of

most important facts to this department of chemical philosophy. He

discovered nitrous air, nitrous oxide, and dephlogisticated air,

(oxygen) and by substituting mercury for water in the pneumatic

apparatus, ascertained the existence of several aëriform bodies

which are rapidly absorbable by water; such as muriatic acid gas,

sulphurous acid gas, and ammonia.

Scheele, independently of Priestley, also discovered several of the

aëriform bodies; he ascertained likewise the composition of the

atmosphere; he brought to light fluoric acid, prussic acid, and

the substance which he termed _dephlogisticated marine acid_, the

oxy-muriatic acid of the French school, and the chlorine of Davy.

Sir Humphry Davy, in the preface to his Chemical Philosophy,

observes that Black, Cavendish, Priestley, and Scheele, were

undoubtedly the greatest chemical discoverers of the eighteenth

century; and that their merits are distinct, peculiar, and of the

most exalted kind. He thus defines them:

"BLACK made a smaller number of original experiments than either of

the other philosophers; but being the first labourer in this new

department of the science, he had greater difficulties to overcome.

His methods are distinguished for their simplicity; his reasonings

are admirable for their precision; and his modest, clear, and

unaffected manner is well calculated to impress upon the mind a

conviction of the accuracy of his processes, and the truth and

candour of his researches.

"CAVENDISH was possessed of a minute knowledge of most of the

departments of Natural Philosophy: he carried into his chemical

researches a delicacy and precision, which have never been

exceeded: possessing depth and extent of mathematical knowledge,

he reasoned with the caution of a geometer upon the results of his

experiments; and it may be said of him, what, perhaps, can scarcely

be said of any other person, that whatever he accomplished, was

perfect at the moment of its production. His processes were all of

a finished nature; executed by the hand of a master, they required

no correction; the accuracy and beauty of his earliest labours even

have remained unimpaired amidst the progress of discovery, and

their merits have been illustrated by discussion and exalted by

time.

"DR. PRIESTLEY began his career of discovery without any general

knowledge of chemistry, and with a very imperfect apparatus. His

characteristics were ardent zeal and the most unwearied industry.

He exposed all the substances he could procure to chemical

agencies, and brought forward his results as they occurred, without

attempting logical method or scientific arrangement. His hypotheses

were usually founded upon a few loose analogies; but he changed

them with facility; and being framed without much effort, they

were relinquished with little regret. He possessed in the highest

degree ingenuousness and the love of truth. His manipulations,

though never very refined, were always simple, and often ingenious.

Chemistry owes to him some of her most important instruments of

research, and many of her most useful combinations; and no single

person ever discovered so many new and curious substances.

"SCHEELE possessed in the highest degree the faculty of invention;

all his labours were instituted with an object in view, and after

happy or bold analogies. He owed little to fortune or to accidental

circumstances: born in an obscure situation, occupied in the duties

of an irksome employment, nothing could damp the ardour of his

mind, or chill the fire of his genius; with very small means, he

accomplished very great things. No difficulties deterred him from

submitting his ideas to the test of experiment. Occasionally misled

in his views, in consequence of the imperfection of his apparatus,

or the infant state of the enquiry, he never hesitated to give

up his opinions the moment they were contradicted by facts. He

was eminently endowed with that candour which is characteristic

of great minds, and which induces them to rejoice as well in the

detection of their own errors, as in the discovery of truth. His

papers are admirable models of the manner in which experimental

research ought to be pursued; and they contain details on some of

the most important and brilliant phenomena of chemical philosophy."

The discovery of the gases, of a new class of bodies more active

than any others in most of the phenomena of nature and art, could

not fail to modify the whole theory of chemistry, and, under the

genius of Lavoisier, it ultimately led to the establishment of

those new doctrines, which it is the principal object of this

history to expound; but before this task can be accomplished, it

will be necessary to consider the rise and progress of opinion

concerning chemical attraction, and heat and light, since these

subjects are too intimately interwoven with the _anti-phlogistic_

system to be separated from any examination of its principles.

Boyle, says Sir Humphry Davy, was one of the most active

experimenters, and certainly the greatest chemist of his age. He

introduced the use of _tests_, or _re-agents_, active substances

for detecting the presence of other bodies: he overturned the ideas

which at that time were prevalent, that the results of operations

by fire were the real elements of things; and he ascertained a

number of important facts respecting inflammable bodies, and

alkalies, and the phenomena of combination; but neither he nor any

of his contemporaries endeavoured to account for the changes of

bodies by any fixed principles.

The solutions of the phenomena were attempted either on rude

mechanical notions, or by occult qualities, or peculiar subtile

spirits or ethers, supposed to exist in the different bodies. And

it is to the same great genius who developed the laws that regulate

the motions of the heavenly bodies, that chemistry owes the first

distinct philosophical elucidations of the powers which produce the

changes and apparent transmutations of the substances belonging to

the earth.

"Sugar dissolves in water, alkalies unite with acids, metals

dissolve in acids. Is not this," says Newton, "on account of an

attraction between their particles? Copper dissolved in aqua fortis

is thrown down by iron. Is not this because the particles of the

iron have a stronger attraction for the particles of the acid, than

those of copper; and do not different bodies attract each other

with different degrees of force?"

In 1719, Geoffroy endeavoured to ascertain the relative attractive

powers of bodies for each other, and to arrange them, under the

form of a table, in an order in which these forces, which he named

affinities, were expressed.

Concerning the nature of heat, there are two opinions which have

ever divided the chemical world. The one considers it merely as a

property of matter, and that it consists in an undefinable motion,

or vibration of its particles; the other, on the contrary, regards

it as a distinct and subtile substance, _sui generis_. Each of

these opinions has been supported by the greatest philosophers,

and for a long period the arguments on both sides appeared equally

plausible and forcible. The discovery of Dr. Black, however, gave a

preponderance to the scale in favour of its materiality.

"It was during his residence in Glasgow, between the year 1759

and 1763," says Dr. Thomson, "that he brought to maturity those

speculations concerning the combination of _heat_ with _matter_,

which had frequently occupied a portion of his thoughts."

Before Dr. Black's discovery, it was universally supposed that

solids were converted into liquids by a small addition of heat,

after they have been once raised to the melting point, and

that they returned again to the solid state on a very small

diminution of the quantity of heat necessary to keep them at

that temperature. An attentive view, however, of the phenomena

of liquefaction and solidification gradually led this sagacious

philosopher to a different conclusion. By observations which

it is unnecessary to detail, he became satisfied that when ice

is converted into water, it unites with a quantity of heat,

without having its temperature increased; and that when water

is frozen into ice, it gives out a quantity of heat without

having it diminished. The heat thus combined, then, is the cause

of the fluidity of the water; and as it is not sensible to the

thermometer, Dr. Black called it _latent heat_.

There is such an analogy between the cessation of thermometric

expansion during the liquefaction of ice, and during the conversion

of water into steam, that there could be no hesitation about

explaining both in the same way. Dr. Black, therefore, immediately

concluded that, as water is ice united to a certain quantity of

_latent_ heat, so steam is water united to a still greater quantity.

This beautiful theory enables us to understand phenomena in nature

which were previously quite inexplicable. We now comprehend how the

thaw which supervenes after intense frost, should so slowly melt

the wreaths of snow and beds of ice. Had, indeed, the transition

of water from its solid into its liquid state not been accompanied

by this great change in its relation to heat, every thaw would

have occasioned a frightful inundation, and a single night's frost

must have solidified our rivers and lakes. Neither animal nor

vegetable life could have subsisted under such sudden and violent

transitions. It would appear, then, that water, during the act of

freezing, is acted upon by two opposite powers: it is deprived of

heat by exposure to a medium whose temperature is below 32°; and

it is supplied with heat by the evolution of that principle from

itself, _viz._ of that portion which constituted its fluidity. As

these powers are exactly equal, the temperature of the water must

remain unchanged till the latent heat, necessary to its fluidity,

is all evolved.

Although these facts have been admitted by all, it has been

contended by many that the absorption of heat by bodies is the

necessary _effect_, and not the efficient _cause_, of change of

form,--the consequence of what has been called a change of their

_capacity_: thus ice, it is supposed, in becoming water, has its

capacity for heat increased, and the absorption of heat is a

consequence of such increased capacity. This theory, however, is

deficient, inasmuch as it fails to explain the cause of that change

of form, which is assumed to account for the increase of capacity.

Light, like heat, has been considered by some philosophers as a

subtile fluid filling space, and rendering bodies visible by the

undulations into which it is thrown; while others, with Newton at

their head, regard it as a substance consisting of small particles,

constantly separating from luminous bodies, moving in straight

lines, and rendering objects visible by passing from them and

entering the eye. The late experiments of Dr. Young would incline

us to prefer the undulatory to the corpuscular hypothesis.

By this preliminary sketch, the reader has been prepared for

viewing with advantage the theory of Lavoisier; in the construction

of which he will see little more than a happy generalization of

the several discoveries which have been enumerated. Indeed, this

observation will apply to all great systems of philosophy; facts,

developed by successive enquirers, go on accumulating, until, after

an interval, a happy genius arises who connects and links them

together; and thus generally receives that meed of praise which, in

stricter justice, would be apportioned and awarded to the separate

contributors. It is far from my intention to disparage the merits

of Lavoisier; but the materials of his system were undoubtedly

furnished by Black, Priestley, and Cavendish.

The most important modification of the phlogistic theory--for

there were several others--may be said to be that suggested by

Dr. Crawford. Dr. Priestley had found that the air in which

combustibles were suffered to burn till they were extinguished,

underwent a very remarkable change, for no combustible would

afterwards burn in it, and no animal could breathe it without

suffocation. Dr. Crawford, like many others, concluded, that this

change was owing to phlogiston; but he for the first time applied

Dr. Black's doctrine of _latent_ heat, for the explanation of the

origin of the heat and light which appear during the process.

According to this philosopher, the phlogiston of the combustible

combines, during combustion, with the air, and at the same time

separates the caloric and light with which that fluid had been

previously united. The heat and the light, then, which appear

during combustion, exist previously in the air. This theory was

very different from Stahl's, and certainly a great deal more

satisfactory; but still the question--_What is phlogiston?_

remained to be answered.

Mr. Kirwan attempted to answer it, and to prove that phlogiston is

no other than hydrogen.

This opinion, which Mr. Kirwan informs us was first suggested

by the discoveries of Dr. Priestley, met with a very favourable

reception from the chemical world, and was adopted, amongst many

others, by Mr. Cavendish. The object of Mr. Kirwan was to prove,

that hydrogen exists as a component part of every combustible body;

that during combustion it separates from the combustible body, and

combines with the oxygen of the air. At the same time, Lavoisier

was engaged in examining the experiment of Bayen, and those of

the British philosophers. Bayen, in 1774, had shown that mercury

converted into a calx, or earth, by the absorption of air, could

be revived without the addition of any inflammable substance; and

hence he concluded, that there was no necessity for supposing

the existence of any peculiar principle of inflammability, in

order to account for the calcination of metals; but he formed no

opinion respecting the nature of the air produced from the _calx_

of mercury. Lavoisier, in 1775, showed that it was an air, which

supported flame and respiration better than common air, which he

afterwards named oxygen: the same substance that Priestley and

Scheele had procured from other metallic bodies the year before,

and had particularly described.

Lavoisier also discovered that the same air is produced during the

revivification of metallic calces by charcoal, as that which is

emitted during the calcination of limestones; hence he concluded,

that this elastic fluid is composed of oxygen and charcoal: and

from his experiments on nitrous acid and oil of vitriol, he also

inferred that this gas entered into the composition of these

substances.

Lavoisier was now enabled to explain the phenomena of combustion,

without having recourse, to phlogiston: a principle merely supposed

to exist, because combustion could not be explained without it.

His new theory depends upon the two laws discovered by himself

and Dr. Black; _viz._ that when a combustible is raised to a

certain temperature, it begins to combine with the oxygen of the

atmosphere, and that this oxygen during its condensation lets go

the _latent_ caloric, and the light with which it was combined

while in the gaseous state. Hence their appearance during every

combustion. Hence also the change which the combustible undergoes

in consequence of combustion.

It followed from this view, that the metallic _calces_ were

combinations of metals with oxygen; and on examining the products

of certain inflammable bodies, and finding them to be acid, the

conclusion was extended by a plausible analogy to other acids whose

bases were unknown, and the general proposition was established

that oxygen was the universal principle of acidity; that acids

resulted from the union of a peculiar combustible base, called the

_radical_, with the common principle, oxygen, technically termed

the _acidifier_.

These views, regarding the phenomena of combustion and

acidification, may be considered as constituting what has been

termed the _Anti-phlogistic system_.

It was some time, however, after this system was promulgated,

before its author was able to gain a single convert, notwithstanding

his unwearied assiduity, and the great weight which his

talents, his reputation, his fortune, and his situation

naturally gave him.

At length, M. Berthollet, at a meeting of the Academy of Sciences

in 1785, solemnly renounced his old opinions, and declared himself

a convert. Fourcroy followed his example; and two years afterwards

Morveau, during a visit to Paris, was prevailed upon to embrace the

new doctrine.

The theory of Lavoisier, soon after it had been framed, received

an important confirmation from the two grand discoveries of Mr.

Cavendish, respecting the composition of water and nitric acid,

and the elaborate and beautiful investigations of Berthollet into

the nature of ammonia; by which, phenomena, before anomalous, were

shown to depend upon combinations of aëriform matter.

The notion of phlogiston, however, was still defended with

remarkable tenacity by many distinguished philosophers. Mr.

Kirwan, who considered hydrogen as the universal principle of

combustibility, undertook to prove that this element entered into

the composition of every body of the kind: a single exception, of

course, must necessarily prove fatal to the theory. Mr. Kirwan,

fortunately for the French chemists, founded his reasonings on the

inaccurate experiments of other chemists; and thus did he promote

the popularity of the anti-phlogistic system by the weakness of the

arguments by which he assailed it.

Lavoisier and his associates saw at once the important uses which

might be made of this essay: by refuting an hypothesis which had

been embraced by the most respectable chemists in Europe, their

cause would receive an _éclat_ which would make it irresistible.

The essay was accordingly translated into French, and each of the

sections into which it was divided was accompanied by a refutation.

Four of the sections were refuted by Lavoisier, three by

Berthollet, three by Fourcroy, two by Morveau, and one by Monge.

Mr. Cavendish, in a paper communicated to the Royal Society in

the year 1784, drew a comparison between the phlogistic and

anti-phlogistic theories, and showed that each of them was capable

of explaining the phenomena in a satisfactory manner; he however,

at the same time, gave the reasons which induced him to prefer the

earlier view. In the execution of this task, unlike Mr. Kirwan, he

never advanced a single opinion which he had not put to the test of

experiment; and he never suffered himself to go any farther than

his experiments would warrant. This paper, therefore, the French

chemists were unable to refute, and they were accordingly wise

enough to pass it over without notice. Had it been possible to have

preserved the phlogistic hypothesis, Mr. Cavendish would have saved

it--

"Si Pergama dextrâ

Defendi possent, etiam hâc defensa fuissent."

"Sooner or later," says Sir Humphry Davy, "that doctrine which

is an expression of facts, must prevail over that which is an

expression of opinion. The most important part of the theory of

Lavoisier was merely an arrangement of the facts relating to the

combinations of oxygen: the principle of reasoning which the French

school professed to adopt was, that every body which was not yet

decompounded, should be considered as simple; and though mistakes

were made with respect to the results of experiments on the nature

of bodies, yet this logical and truly philosophical principle was

not violated; and the systematic manner in which it was enforced

was of the greatest use in promoting the progress of science."

Till 1786, there had been no attempt to reform the nomenclature of

chemistry; the names applied by discoverers to the substances which

they made known were still employed. Some of these names, which

originated amongst the alchymists, were of the most barbarous kind;

few of them were sufficiently definite or precise, and most of them

were founded upon loose analogies, or upon false theoretical views.

"It was felt by many philosophers, particularly by the illustrious

Bergman, that an improvement in chemical nomenclature was

necessary; and in 1787, MM. Lavoisier, Morveau, Berthollet, and

Fourcroy, presented to the world a plan for an almost entire change

in the denomination of chemical substances, founded upon the idea

of calling simple bodies by some names characteristic of their

most striking qualities, and of naming compound bodies from the

elements which composed them." There was, besides, a secret feeling

in the breasts of the associated chemists, which, no doubt, had its

influence in suggesting and promoting such a scheme. The views of

Lavoisier had so changed the face of chemistry, as almost to have

rendered it a new science: by adopting a new nomenclature, they

identified, as it were, all the discoveries of the day with the new

theory, and thus appropriated to France the original and entire

merit of the system.

It is impossible to pass over this subject without a comment.

Lavoisier was unquestionably indebted to Dr. Black for the support,

if not for the suggestion, of the most brilliant part of his theory

of combustion; and yet he attempted even to conceal the name of the

discoverer of _latent heat_.

How far Lavoisier was really culpable, and whether he did not

intend to do full justice to all the claims of his predecessors,

cannot now be known; as he was cut off in the midst of his career,

while so many of his scientific projects remained unexecuted.

From the posthumous works of Lavoisier, there is some reason for

believing that, if he had lived, he would have done justice to

all parties; but there is no doubt that Dr. Black, in the mean

time, thought himself aggrieved by the publication of several

of Lavoisier's papers in the "Mémoires de l'Académie," and that

he formed the intention of doing himself justice, by publishing

an account of his own discoveries: this intention, however, was

unfortunately thwarted and prevented by bad health. But to return

to the subject of nomenclature. Sir H. Davy continues--"The

new nomenclature was speedily adopted in France; under some

modifications, it was received in Germany; and, after much

discussion and opposition, it became the language of a new and

rising generation of chemists in England. It materially assisted

the diffusion of the anti-phlogistic doctrine, and even facilitated

the general acquisition of the science; and many of its details

were contrived with much address, and were worthy of its celebrated

authors."

On the general adoption of this new theory of chemistry, it must be

admitted that its authors displayed an intemperate triumph wholly

unworthy of them. They held a festival, at which Madame Lavoisier,

in the habit of a priestess, burnt the works of Stahl on an altar

erected for the occasion, while solemn music played a requiem to

his departed system!

Sir Humphry Davy, in speaking of the merits of Lavoisier,

observes that "he must be regarded as one of the most sagacious

of the chemical philosophers of the last century; indeed, except

Cavendish, there is no other enquirer who can be compared to him

for precision of logic, extent of view, and sagacity of induction.

His discoveries are few, but he reasoned with extraordinary

correctness upon the labours of others. He introduced weight and

measure, and strict accuracy of manipulation into all chemical

processes. His mind was unbiassed by prejudice; his combinations

were of the most philosophical nature; and in his investigations

upon ponderable substances, he has entered the true path of

experiment with cautious steps, following just analogies, and

measuring hypotheses by their simple relations to facts."

It will be scarcely possible for a future generation of

philosophers to imagine with what an undisciplined ardour the

anti-phlogistic system, thus enhanced by a new and fascinating

nomenclature, was supported throughout Europe. Facts only were

appreciated in proportion to the evidence they furnished of its

truth; and a discovery even required the sanction of its authority

as the passport to notice and regard. The least expression of

doubt, as to the validity of any point in its doctrines, exposed

the sceptic to a host of assailants, and fortunate was he if he

escaped the fate of Peter Ramus, or of those who ventured to

question the infallibility of that great despot of another age,

Aristotle.

In no country of Europe did this feeling manifest itself to a

greater extent than in England. There was perhaps a political

prejudice co-operating upon the occasion: it is very difficult,

under any circumstances, to avoid connecting the man and his

works. The fate of Lavoisier[133] was truly affecting, and by a

species of retributive justice, he received the sympathy of the

world in the homage paid to his system; while the atrocity of

his assassination, on which every Englishman dwelt with horror,

appeared to be thus heightened by every praise bestowed upon his

merits.

[133] Lavoisier perished on the scaffold at the age of

fifty-one, during the sanguinary reign of Robespierre. The

fury of the revolutionary leaders of France was particularly

directed against the farmers-general of the revenue, who were

all executed, with the exception of a single individual, a M.

de Verdun. Sixty of them were guillotined at the same time,

in consequence of a report of Dupin, a frantic member of the

Convention. The revolutionary tribunal adopted a general formula,

as the ground of their condemnation, which is curious as applied

to Lavoisier, who was declared guilty of having "adulterated

snuff with water and ingredients destructive of the health of

the citizens." The unfortunate philosopher requested time to

complete some experiments on respiration. The reply of Coffinhal,

the President, was, that "the Republic did not want savans or

chemists, and that the course of justice could not be suspended."

It is not the least surprising circumstance in the history of

this system, that with such a blind and idolatrous admiration of

its principles, so few facts should have been distorted. It is

true that, from the belief that combustion could never take place

without the presence of oxygen, the elementary principle of Scheele

became, according to these views, a compound of oxygen and an acid;

and the name of _dephlogisticated marine acid_ was exchanged for

that of _oxy-muriatic acid_, a circumstance which spread a cloud

of error over the science, and perhaps retarded its progress in

a greater degree than is generally imagined. In like manner, the

chemist neglected to avail himself of the hint which, under other

impressions, would have proved an important clue to discovery,

_viz._ the acid properties of sulphuretted hydrogen.

We have now arrived at that stage in our history, when it may with

propriety and advantage be asked--WHAT HAS DAVY DONE IN CORRECTING

ERROR, OR IN ADVANCING TRUTH?

The answer to this question will be nothing more than a summary of

those discoveries which have been successively investigated during

the progress of the present work.

The new doctrines of chemistry were highly instrumental in

encouraging more extended investigations into all the different

productions of nature and art; and we may observe, that one of the

first efforts of Sir Humphry Davy was to improve our knowledge of

the nature and habitudes of the tanning and astringent principles

of vegetables,--an enquiry which had been commenced by Seguin and

Proust. In pursuing even the most beaten path, he was sure to

discover objects of novelty. Look at his early experiments on the

cane, and on the straw of wheat, barley, and hay, and we shall see

how magically he raised from their ashes a new flower of knowledge.

He soon, however, quitted the track of other experimentalists;

although we learn from the whole tenor of his researches, that he

could obey as well as he could command, and he could act in the

ranks, although he more frequently appeared as a general in the

field of science.

Sir Humphry Davy has observed, that "at the time when the

anti-phlogistic theory was established, electricity had little or

no relation to chemistry. The grand results of Franklin respecting

the cause of lightning, had led many philosophers to conjecture,

that certain chemical changes in the atmosphere might be connected

with electrical phenomena; and electrical discharges had been

employed by Cavendish, Priestley, and Van-Marum, for decomposing

and igniting bodies; but it was not till the era of the wonderful

discovery of Volta, in 1800, of a new electrical apparatus, that

any great progress was made in chemical investigation by means of

electrical combinations.

"Nothing tends so much to the advancement of knowledge as the

application of a new instrument. The native intellectual powers of

men in different times are not so much the causes of the different

success of their labours, as the peculiar nature of the means and

artificial resources in their possession. Independent of vessels of

glass, there could have been no accurate manipulations in common

chemistry: the air-pump was necessary for the investigation of the

properties of gaseous matter; and without the Voltaic apparatus,

there was no possibility of examining the relations of electrical

polarities to chemical attractions."

There is a candour in this statement which we cannot but admire.

Nor does the admission diminish the glory of him who, by the

application of such new instruments of research, was enabled to

penetrate into the hidden mysteries of Nature. What avails the

telescope, without the eye of the observer?

To Davy, the Voltaic apparatus was the _golden branch_, by which

he subdued the spirits that had opposed the advance of former

philosophers; but what would its possession have availed him, had

not his genius, like the ancient Sibyl, pointed out its use and

application?

It will be seen that he was thus enabled, not only to discover laws

which are in constant operation, modifying the forms of matter, and

influencing all the operations of chemistry, but, by applying them,

to determine the elements of the fixed alkalies to be oxygen and a

metallic base: a fact obviously opposed to the idea of oxygen being

the general principle of acidity; for here it was the principle

of alkalinity, if it may be so expressed. This was shaking the

corner-stone of the edifice, and his subsequent researches into

the nature of oxy-muriatic acid may be said to have overthrown it;

for if either of the elements of this body can be considered as

the acidifier, it is hydrogen. The consequences which flowed from

this truth were of the highest importance, not only in correcting

errors, which the progress of discovery, instead of rectifying,

was actually multiplying, but in leading to the developement of

new bodies. Iodine might have been recognised as an elementary

body; but its relations to oxygen and hydrogen would probably have

remained unknown, had not a knowledge of the true character of

chlorine assisted the enquiry.

The same observation will apply to the recently discovered body,

Bromine. In like manner has the chemist been led, by the chloridic

theory, to a more accurate acquaintance with the composition of

the fluoric, hydriodic, and hydrocyanic acids; while he has also

learnt that hydrogen alone can convert certain undecompounded bases

into well characterised acids, without the aid of oxygen. The same

discovery has completely changed all our opinions with regard to

a very important series of saline combinations, and developed the

existence of new compounds of a most interesting description.

Thus, then, has the _acidifying_ hypothesis of Lavoisier been

overturned, and a new theory constructed out of its ruins, which

acknowledges no distinct element as the one imparting to matter the

characters of an acid.

Equally complete has been the downfall of the theory of combustion.

The discovery of the true nature of chlorine was, in itself,

sufficient to show that bodies might combine, with the phenomena

of heat and light, without the presence of oxygen; but Davy has

brought a mass of evidence from other sources in proof of the

same truth. He has shown that, whenever the chemical forces which

determine either composition or decomposition are energetically

exercised, the phenomena of combustion, or incandescence, with a

change of properties, are displayed. He has therefore annulled the

distinction between supporters of combustion and combustibles,

since he has shown that, in fact, one substance frequently acts in

both capacities, being a supporter _apparently_ at one time, and a

combustible at another. But in both cases the heat and light depend

on the same cause, and merely indicate the energy and rapidity

with which reciprocal attractions are exerted. Thus sulphuretted

hydrogen is a combustible with oxygen and chlorine; a supporter

with potassium. Sulphur, with chlorine and oxygen, has been called

a combustible basis; with metals, it acts the part of a supporter.

In like manner, potassium unites so powerfully with arsenic and

tellurium, as to produce the phenomena of combustion. Nor can

we ascribe the appearances to the liberation of latent heat, in

consequence of condensation of volume. The protoxide of chlorine,

a body destitute of any combustible constituent, at the instant of

decomposition evolves light and heat with explosive violence; and

its volume becomes one-fifth greater. Chloride and iodide of azote,

compounds alike destitute of any inflammable matter, according to

the ordinary belief, are resolved into their respective elements

with tremendous force of inflammation; and the first expands

into more than six hundred times its bulk. Now, instead of heat

and light, a prodigious degree of _cold_ ought to accompany such

an expansion, according to the hypothesis of latent heat. Other

instances might be cited, and other arguments adduced on the same

subject, but time and space fail me.[134]

[134] The reader who wishes for further details, will consult

with advantage the article Combustion in Dr. Ure's Dictionary of

Chemistry; a work to which I acknowledge myself much indebted on

this and other occasions.

Such, then, are the facts developed by the experimental researches

of Sir Humphry Davy; from which it follows, that--

1. Combustion is not necessarily dependent on the agency of oxygen.

2. That it cannot be regarded as dependent upon any peculiar

principle or form of matter, but must be considered as a general

result of intense chemical action.

3. That the evolution of light and heat cannot be ascribed simply

to a gas parting with its latent store of those ethereal fluids.

4. That, since all bodies which act powerfully upon each other are

in the opposite electrical relations of positive and negative, the

evolution of heat and light may depend upon the annihilation of

these opposite states, which will happen whenever they combine.

Thus has Sir H. Davy, by refuting the opinions of the French

philosophers, respecting the relations of oxygen to the phenomena

of combustion, and the nature of its products, removed the pillars

on which the fabric of the anti-phlogistic rested, and reduced the

generalization of Lavoisier to isolated collections of facts; the

sound logic, however,--the pure candour, the numerical precision of

inference which characterise the labours of the French philosopher,

will cause his name to be held in everlasting admiration. The

downfall of his doctrine is the natural result of the progress of

truth; the same fate may attend our present systems, but the facts

discovered through their means are unchangeable and eternal; and

it is upon them alone that the fame of the chemist must ultimately

rest.

In sciences collateral to chemistry, the researches of Davy

have cast a reflected lustre. In geology, his discovery of the

composition of the earths, has opened a new path of investigation;

while his examination of the water and gaseous matter so frequently

enclosed in the cavities of quartz, has given no small degree of

support to the hypothesis of the Plutonists; above all, his results

connected with the decomposition and transfer of different elements

by Voltaic influence, has already explained many phenomena relating

to metallic veins; and the late researches of Mr. Fox must lead us

to the conclusion, that electric powers are still in operation in

the recesses of the earth; and that mineral veins are not only the

cabinets of Nature, but still her active laboratories.

These cursory observations upon the discoveries of Sir H. Davy

relate merely to the changes they have effected in the general

theory of chemistry. I might recapitulate the numerous researches

by which he has extended our knowledge upon particular subjects;

but I have so fully entered into the consideration of them in the

body of my work, that I consider such a tax upon the patience of my

reader would be both unfair and unnecessary.

I shall therefore _conclude_ my long and arduous labour,

by enumerating the different memoirs communicated by this

distinguished philosopher to the Royal Society; and also the

several works which he published at different periods of his

brilliant but too fleeting career.

1. An Account of some Galvanic Combinations, formed by single

metallic plates and fluids, analogous to the Galvanic Apparatus

of M. Volta.

_Read June 18, 1801._

2. An Account of some Experiments and Observations on the

constituent parts of certain Astringent Vegetables, and on

their operation in Tanning.

_February 24, 1803._

3. An Account of some Analytical Experiments on a Mineral

Production from Devonshire, consisting principally of Alumina

and Water.

_February 28, 1805._

4. On a Method of analysing Stones containing a fixed Alkali,

by means of Boracic acid.

_May 16, 1805_.

* _For the above papers, the Society awarded him the Copley

Medal._

5. THE BAKERIAN LECTURE.--On some Chemical agencies of

Electricity.

_November 20, 1806._

** _For this memoir, he received the prize of the French

Institute._

6. THE BAKERIAN LECTURE.--On some new Phenomena of Chemical

Changes produced by Electricity, particularly the Decomposition

of the Fixed Alkalies, and the exhibition of the new substances

which constitute their bases; and on the general nature of

Alkaline bodies. 3?

_Read November 19, 1807._

7. Electro-chemical Researches on the Decomposition of the

Earths; with Observations on the Metals obtained from the

Alkaline Earths; and on the Amalgam procured from Ammonia.

_June 30, 1808._

8. THE BAKERIAN LECTURE.--An Account of some new Analytical

Researches on the nature of certain bodies, particularly the

Alkalies, Phosphorus, Sulphur, Carbonaceous matter, and the

Acids hitherto uncompounded; with some general Observations on

Chemical Theory.

_December 15, 1808._

9. New Analytical Researches on the nature of certain bodies;

being an Appendix to the Bakerian Lecture for 1808.

_February 1809._

10. THE BAKERIAN LECTURE FOR 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.

_November 16, 1809._

11. Researches on the Oxy-muriatic Acid, its nature and

combinations; and on the elements of Muriatic Acid; with some

Experiments on Sulphur and Phosphorus, made in the Laboratory

of the Royal Institution.

_Read July 12, 1810._

12. THE BAKERIAN LECTURE FOR 1810. On some of the Combinations

of Oxy-muriatic Gas and Oxygen, and on the chemical relations

of those principles to inflammable bodies.

_November 15, 1810._

13. On a Combination of Oxy-muriatic Gas and Oxygen Gas.

_February 21, 1811._

14. On some Combinations of Phosphorus and Sulphur, and on some

other subjects of Chemical Enquiry.

_June 18, 1812._

15. On a new Detonating Compound; in a letter to Sir Joseph

Banks, Bart. F.R.S.

_November 5, 1812._

16. Some further Observations on a new Detonating substance.

_July 1, 1813._

17. Some Experiments and Observations on the Substances

produced in different chemical processes on Fluor Spar.

_July 8, 1813._

18. An Account of some New Experiments on the Fluoric

Compounds; with some Observations on other objects of Chemical

Enquiry.

_February 13, 1814._

19. Some Experiments and Observations on a new Substance, which

becomes a Violet-coloured Gas by heat.

_January 20, 1814._

20. Further Experiments and Observations on Iodine.

_Read June 16, 1814._

21. Some Experiments on the Combustion of the Diamond, and

other Carbonaceous Substances.

_June 23, 1814._

22. Some Experiments and Observations on the Colours used in

Painting by the Ancients.

_February 23, 1815._

23. Some Experiments on a solid Compound of Iodine and Oxygen,

and on its Chemical Agencies.

_April 20, 1815._

24. On the Action of Acid upon the Salts usually called

_Hyper-Oxymuriates_, and on the Gases produced from them.

_May 4, 1815._

25. On the _Fire-damp_ of Coal Mines, and on methods of

lighting the Mine, so as to prevent Explosion.

_November 19, 1815._

26. An Account of an Invention for giving Light in Explosive

Mixtures of _Fire-damp_ in Coal Mines, by consuming the

Fire-damp.

_January 11, 1816._

27. Further Experiments on the Combustion of Explosive Mixtures

confined by Wire Gauze, with some Observations on Flame.

_January 25, 1816._

28. Some Researches on Flame.

_January 16, 1817._

29. Some New Experiments and Observations on the Combustion of

Gaseous Mixtures; with an account of a method of preserving

a continued Light in Mixtures of inflammable Gases and Air,

without Flame.

_Read January 23, 1817._

*** _For the preceding five papers, the Rumford Medals were

awarded to him._

30. On the fallacy of Experiments in which Water is said to

have been formed by the decomposition of Chlorine.

_February 12, 1818._

31. New Experiments on some of the combinations of Phosphorus.

_April 9, 1818._

32. Some Observations on the formation of Mists in particular

situations.

_February 25, 1819._

33. On the Magnetic Phenomena produced by Electricity.

_November 16, 1820._

34. Some Observations and Experiments on the Papyri found in

the ruins of Herculaneum.

_March 15, 1821._

35. Further Researches on the Magnetic Phenomena produced by

Electricity; with some new Experiments on the properties of

Electrified bodies, in their relations to conducting powers and

temperature.

_July 5, 1821._

36. On the Electrical Phenomena exhibited _in vacuo_.

_December 20, 1821._

37. On the state of Water and Aëriform matter in cavities

found in certain Crystals.

_Read June 13, 1822._

38. On a new Phenomenon of Electro-Magnetism.

_March 6, 1823._

39. On the application of Liquids formed by the condensation of

Gases, as mechanical Agents.

_April 17, 1823._

40. On the changes of volume produced in Gases, in different

states of density, by Heat.

_May 1, 1823._

41. On the Corrosion of Copper Sheathing by sea-water; and on

methods of preventing this effect, and on their application to

ships of war and other ships.

_Jan. 24, 1824._

42. Additional Experiments and Observations on the application

of Electrical Combinations to the preservation of the Copper

Sheathing of ships, and to other purposes.

_June 17, 1824._

43. Further Researches on the preservation of Metals by

Electro-chemical means.

_June 9, 1825._

44. THE BAKERIAN LECTURE for 1826.--On the Relation of

Electrical and Chemical changes.

_June 3, 1826._

**** _For this memoir, the Royal Society conferred upon him the

Royal Medal._

45. On the Phenomena of Volcanoes.

_March 20, 1828._

46. Account of some Experiments on the Torpedo.

_November 20, 1828._

HIS PUBLISHED WORKS ARE,

"Experimental Essays on Heat, Light, and on the Combinations

of Light, with a new Theory of Respiration," &c. Published in

_Contributions to Physical and Medical Knowledge, by T. Beddoes,

M.D._ 1799.

"Researches Chemical and Philosophical, chiefly concerning Nitrous

Oxide, and its Respiration." 1800.

"A Syllabus of a Course of Lectures."

"An Introductory Lecture." 1801.

"Elements of Chemical Philosophy." 1812.

"Elements of Agricultural Chemistry." 1813.

"On the Safety Lamp for Coal Miners; with some Researches on

Flame." 1818. (Several Editions.)

"Salmonia; or Days of Fly-Fishing."

"Consolations in Travel; or the Last Days of a Philosopher."

APPENDIX.

APPENDIX.

EXTRACTED FROM THE REGISTRY OF THE PREROGATIVE COURT OF CANTERBURY.

A.

MY WILL.

This 3rd of January 1827 feeling more than usual symptoms of

mortality I make this my Will. First, I give my Brother John Davy

M.D. three hundred pounds a-year of money that I possess in the

Long Annuities and likewise four thousand pounds to be raised by

the sale of Securities I possess in the English or French funds

or annuities but I mean my said Brother to devote the interest

of three thousand pound of these last moneys to such purposes as

he may deem fitting for the benefit of my sisters particularly

my married one and I wish a part of the interest of these three

thousand pounds to be employed in educating and settling in life

my godson Humphrey Millett. I leave him Dr. Davy likewise all the

property devolving to me from my parents which has never been

divided to do what seems to him best for the benefit of my sisters

and my sister Millett's children and I leave my said brother my

Chemical Books and Chemical MSS. Apparatus _Sporting tackle_

Medals and the silver Venetian dish made from the Rumford Medal in

token of my affection. I leave £100 to each of these friends Dr.

Babington and Dr. Franck and £50 to Dr. Wilson Philip and to Mr.

Brodie surgeon to lay out in tokens of remembrance. I leave all my

other property whether in goods money chattels funded securities

annuities or plate to my wife (Lady) Jane Davy and I appoint her

the sole Executrix of this my Will. If my brother or his family

should not be in a condition at the time of her decease to use my

service of plate given for the safety lamp I wish it to be sold and

the same given to the Royal Society to provide an annual medal from

the interest for the best discovery made any where in chemistry and

I depend upon my dear wife to make such presents in seals or token

to such of my friends as she may think proper agreeably to their

and her feelings.

H. DAVY.

B.

Further explanatory Clause.

I leave to my wife Dame Jane Davy all my other property whether

funded or in government securities or in leases of houses or goods

&c. and I leave her my sole residuary legatee and sole Executrix.

I wish her to enjoy the use of my plate during her life and that

she will leave it to my brother in case he survive her and if not

to any child of his who may be capable of using it but if he be not

in a situation to use or enjoy it then I wish it to be melted and

given to the Royal Society to found a medal to be given annually

for the most important discovery in Chemistry any where made in

Europe or Anglo-America. Knowing the perfect understanding and love

of justice of my wife I leave to her all other arrangements which

may make my memory useful to the world and awaken the kind feelings

of my friends and I wish her and my brother and all my friends

every happiness this life can afford.

HUMPHRY DAVY.

C.

That is a Clause explanatory of my Will.

I wish seals not rings with a fish engraved upon them to be

given to some of my friends amongst whom I mention Mr Knight Dr

Babington Mr Pepys Mr Hatchett. And lest there should be any doubt

respecting the £3000 mentioned I mean my brother to be a trustee

for this and should he die without children I mean it to belong to

my sister Millett's children £2000 to Humphry Millett my godson

and the rest to be equally divided between the other children but

should my brother marry and have children I then mean after the

death of my sisters these £3000 to be divided between her child

or children and my sisters and £1000 to go to Humphry Millett

my godson and £500 to my sister's other children leaving the

arrangement to my brother.

H. D.

D.

Further explanatory Clause, Feb. 27th 1828.

I leave to my brother John Davy M.D. the proceeds of my

Agricultural Chemistry in the future editions and the profits of

my work on fishing and I give him the copyright. I leave my friend

Thomas Poole Esq. of Stowey fifty pounds to purchase some token of

remembrance.

H. D.

* * * * *

Rome Nov. 18th, 1828.

By this addition to my will I confirm all that I have willed in a

paper left in a brass box at Messrs. Drummond leaving Lady Davy

my sole Executrix and residuary legatee. I leave the copyright of

Salmonia to my brother John Davy wishing him to apply a part of the

profits of the sale of the editions of this work to the education

of my nephew Humphrey Millett in case he has no children of his

own. I leave the copy of my Vision in my writing desk to Lady

Davy to be published if my friends think it may give pleasure or

information to the public but I wish the profits of this work to be

applied to the use of my brothers and sisters. I leave to Josephine

Detela daughter of Mr. Detela of Laybach in Illyria innkeeper my

kind and affectionate nurse one hundred pounds or rather a sum

which shall equal a thousand florins to be paid out of the balance

at my banker's within three months after my decease. I beg Lady

Davy to be so good as to fulfill my engagements with the persons

who are travelling with me but without any favour as I have no

reason to praise either their attention or civilities within the

last two months but the kindness and attentions of Josephine Detela

during my illness at Laybach not only calls for the testimony I

have given but likewise my gratitude for which I give her the £100

or the 1000 florins.

H. DAVY.

* * * * *

Feb. 19th 1829.

I wish to be buried where I die _natura curat suas reliquias_.

I wish £100 to be given to George Whidby and I beg Lady Davy to

fulfill all my engagements and that if my friends should think my

Dialogues worthy of publication I beg that they may be published

and that Mr. Tobin may correct the press of them and I wish that

£150 may be given to him for this labour. There is a codicil to my

will in my writing desk. I beg Lady Davy to have the goodness to

attend to every thing mentioned in that. In addition to what I have

mentioned in that codicil I request that £50 or 500 florins may be

given to Josephine Dettela within five months after my decease and

I wish £50 to be presented to my friend Dr Morichini in remembrance

and memory of his great kindness to me.

H. D.

I wish one hundred to be given to my amanuensis.

* * * * *

For the purpose of explaining a Will that I made before I left

England and some papers that I have since added to it I write these

few words Rome, March 18, 1829.

I give the copyright of Salmonia my Dialogues and any other of

my works which my friends may think it proper to republish to my

brother John Davy M.D. to be published in the manner he may think

most fit and proper. I have already in my former testament left

Lady Davy my residuary legatee but I beg her in considering the

disposition of my property to regard £6000 as belonging to my

brother Dr. Davy in case there rests any doubt upon this subject

in my first will and I wish her the said Lady Davy to enjoy during

her life the use and property of the different services of plate

given to me whether by the Emperor of Russia or the different

coal _committees_ but I trust to her sense of justice that she

will leave them in the manner I have pointed out in my will to my

brother. With respect to any property at present in my banker's

hands or any thing I now carry with me I leave them entirely to my

brother Dr. Davy.

HUMPHRY DAVY.

At Rome March 18, 1829.

THE END.

LONDON:

PRINTED BY SAMUEL BENTLEY,

Dorset Street, Fleet Street.

Transcriber's note:

Minor spelling and punctuation inconsistencies, and hyphenated

words, have been harmonized. The formatting of the letters

has been regularized.