Chapter XVII: Part III: ‘The Chemistry of the Arts.’ Div. 1, of Agriculture; Div (2)

On January 18 he wrote, ‘Capital result from the action of potassium on ammonia. Nitrogen was lost. If the nitrogen is to be considered as converted into oxygen and hydrogen, it must be regarded as containing much more oxygen than water; and if we do not adopt this supposition, the only alternative is that water is the ponderable matter which, under different modifications of electro-chemical existence, constitutes oxygen, hydrogen, nitrogen, and the nitrous compounds.’

On February 15 he wrote in the Laboratory Book, ‘Were a description, indeed, to be given of all the experiments I have made, of all the difficulties I have encountered, of the doubts that have occurred, and the hypotheses formed--’ The sentence was not finished, and more time was lost on the investigation.

Throughout the spring and summer more experiments were made on ammonia and nitrogen.

He ignited potassium by the voltaic spark in nitrogen, and found that some hydrogen was evolved and some nitrogen lost; but when the potassium was free from potash this did not occur, and at last he gave up trying to show that nitrogen was a compound of oxygen and a metallic basis.

At the end of August he was working on tellurium and made telluretted hydrogen.

To his mother he wrote in August:

At present, except when I resolve to be idle for health’s sake,
I devote every moment to labours which I hope will not be wholly
ineffectual in benefiting society, and which will not be wholly
inglorious for my country hereafter; and the feeling of this is the
reward which will continue to keep me employed.

On September 13 he wrote in the Laboratory Book this verbal picture of his laboratory:

Objects much wanted in the laboratory of the Royal Institution:
Cleanliness, neatness, and regularity.

The laboratory must be cleaned every morning when operations are
going on before ten o’clock.

It is the business of W. Payne[38] to do this, and it is the duty
of Mr. E. Davy to see that it is done and to take care of and keep
in order the apparatus.

There must be in the laboratory pen, ink, paper, and wafers, and
these must not be kept in the slovenly manner in which they usually
are kept. I am now writing with a pen and ink such as was never
used in any other place.

There are wanting small graduated glass tubes blown here and
measured to ten grains of mercury.

There are wanting four new stopcocks fitted to our air-pump.

There are wanting twelve green glass retorts.

There are wanting most of the common metallic and saline solutions,
such as acetate of copper, nitrate of silver, nitrate of
barytes--most of these made in the laboratory.

All the wine-glasses should be cleaned.

And, as all operation ceases at six o’clock in the evening, there
is plenty of time for getting things in order before night; but if
they are not got into order the same night, they must be by ten
o’clock the next day.

The laboratory is constantly in a state of dirt and confusion.

There must be a roller with a coarse towel for washing the hands
and a basin of water and soap, and every week at least a whole
morning must be devoted to the inspection and ordering of the
voltaic battery.

For Thursday--_i.e._ to-morrow--the experiments in the morning
are on the excitation of radiant heat and electricity in different
gases. For the experiments on Friday, which will be on tellurium,
there are wanting very pure hydrogen; two bottles of _new_, very
pure oxymuriatic gas; two new stopcocks cemented into retorts,
with stoppers, either green or white; some tubes of this bore
or near it, closed at one end and six inches long;
a spirit lamp made from a phial of large bore and the tube larger
than that at present used.

On September 14 he tried various experiments on the excitation of electricity. The Laboratory Book says, ‘Present in these and the former experiments, Mr. Cavendish, Dr. Herschel, Mr. Herschel, Sir Charles Blagden (not in the second set on electricity); Dr. Wollaston, Mr. Warburton.’

The repulsion of the machine was compared to the repulsion in a partial vacuum, in hydrogen, in carbonic acid, and in rarefied carbonic acid. The former experiments the same day were on the rise of a thermometer heated by a coil of platinum wire in different gases.

On September 21 the Note-Book says:

_An Experiment to Decompose Muriatic Acid Gas._--A balloon
having three openings, to one of which a stopcock was cemented,
and in the other two were corks containing wires, so adapted to
each other that a contact might be made. Pieces of well-burnt
charcoal were fastened to the ends of the wires. The apparatus,
being air-tight, was exhausted and filled with hydrogen; another
exhaustion being made, the balloon was filled with oxymuriatic
gas from a gas-holder, with which it was connected by means of a
stopcock. The two wires being joined to the voltaic apparatus and
a contact of the charcoal made, the ignition was brilliant without
any apparent combustion; white fumes were presently produced, which
in a short time disappeared again, and were afterwards, during the
remaining time the experiment was in hand, only formed when two new
points of charcoal came in contact, or when the flame played on the
copper wire which fastened the charcoal. The light emitted was a
brilliant yellowish colour, frequently assuming a fine lake. After
an hour’s time the gas appeared unaltered, of its original colour.
The higher parts of the pieces of charcoal were covered with a fine
greenish-yellow powder, otherwise unaltered.

Tin-leaf thrown in through one of the openings began immediately to
form with the oxymuriatic acid gas the fuming liquor of Libavius.
When shook it inflamed.

On September 23, 1809, in a letter to Mr. Children, he mentions this experiment, and says ‘it is as difficult to decompose as nitrogen, except when all its elements can be made to enter into new combinations.’

On October 3, among ‘the hints for experiments’ in the Note-Book is this, to detonate together hydrogen and oxymuriatic acid.

Another Bakerian lecture was given, and then he continued his researches on ammonia.

On November 24 ‘experiments to be in progress’ are thus entered in the Laboratory Book:

1. To decompose sulphuretted hydrogen by electricity in an
apparatus by which the results can be accurately known.

2. To pass potassium through ignited powdered quartz.

3. To decompose muriatic acid gas by potassium, so as to ascertain
the quantity of hydrogen formed.

4. To weigh ammonia, hydrogen, and nitrogen, sulphuretted hydrogen
and gaseous fluoric acid, nitrous oxide, and oxymuriatic acid gas.

5. To make a series of experiments upon the ores and products of
cast iron.

6. To ascertain with greater precision than has been yet obtained
the nature of the acid matter formed in pure water, oxygenated or
not.

7. To decompose fluoric acid gas, and to ascertain the source of
the hydrogen which it gives by the operation of potassium.

8. To make various experiments on the amalgamation of ammonia,
using different amalgams of mercury and different modes of
excluding water.

9. To endeavour to bring the ὑδὼρ theory to a test of producing
oxygen from water without hydrogen.

10. To decompose muriate of soda and litharge and other bodies that
contain no water by electricity, and to see what happens.

In the early part of 1810 the experiments were chiefly on the action of potassium on sulphur and phosphorus.

From analogy oxygen had been considered as the acidifying principle of the muriatic acid, or spirit of salt. It was thought to combine with more oxygen, and then was called oxygenated muriatic acid, although its powers as an acid were weakened and it became more volatile and bleached.

Davy sent two papers to the Royal Society, on this subject. The first was on July 12, ‘Researches on Oxymuriatic Acid and the Elements of Muriatic Acid; with Experiments on Sulphur and Phosphorus,’ and the second, on November 15, was the ‘Bakerian Lecture on Some of the Combinations of Oxymuriatic Gas and Oxygen, and on the Chemical Relations of these Principles to Inflammable Bodies.’

In the first paper he says, ‘Scheele considered oxymuriatic acid as more simple than muriatic acid, and that it became muriatic acid by union with phlogiston. Berthollet said it contained oxygen. The vivid combustion of many bodies in this gas has favoured the presumption that it contained oxygen very loosely combined, and ready to exert its utmost power of affinity; but it is mere presumption, since heat and light result also from the intense agency of any other combination without the presence of oxygen.’

On July 3 he wrote, ‘Equal parts of oxymuriatic acid and hydrogene, both dried, were detonated. There was a diminution equal to about 1/12, and muriatic gas was formed; and this was over mercury, and some of the oxymuriatic acid burnt the mercury, and there was an excess of 1/4 hydrogene. Equal parts of oxymuriatic acid and sulphuretted hydrogene, diminution about 1/12. Muriatic gas formed; sulphuretted hydrogene apparently in excess.’

A most important experiment had been made on September 21, 1809, on the resistance of oxymuriatic acid to galvanic decomposition; and as long previously as April 19, 1808, he had decomposed muriatic acid with a battery of 520 pair of plates.[39]

The experiments which were detailed in the Bakerian lecture read during the absence of Davy on November 15, were made in July and August.

On August 30, after entering things wanted, he wrote in the Laboratory Book:

‘No experiments are to be made or carried on in the laboratory without the consent and approbation of the Professor of Chemistry. The attempt at original experiment, unless preceded by knowledge, merely interferes with the progress of discovery. There are a sufficient number of new and interesting objects which a modest student would wish to pursue, and in which the path is marked and distinct.’

On September 8 he was again experimenting on the decomposition of nitrogen. He wrote, ‘And if it be said that no air and no water were present (in the potassium, boracic acid, and ammonia), the experiment is decisive as to the destruction of nitrogen and its containing the same kind of elementary matter as water.’

To the like experiment, September 13, he wrote, ‘This experiment seems almost decisive on the decomposition of nitrogen.’

Soon after he wrote, ‘Query, Does not the general tenor of the last experiments lead to the suspicion of the decomposition of nitrogen?’

On September 16 he made this note: ‘Objects to be attempted during the next week: To-morrow, oxymuriatic acid pure, to try absorption by two grains of different metals--tin, arsenic, antimony, bismuth, copper, platina, lead, zinc.’

On October 4, when he was about to start for Dublin, he wrote in the Laboratory Book, ‘The principal thing, the laboratory in complete order.’ He was absent from October 4 to the middle of December. No experiments were entered until October 27; then there are some on oxymuriatic acid by E. Davy.

On November 15 the action of oxymuriatic gas on dried nitrous gas was repeated.

The next experiment was on November 24. ‘Two grains of silver were entirely converted into horn-silver; the absorption of chlorine gas was 9/10 of a cubic inch.’ This was the first use of the word CHLORINE in the Note-Book; it occurs daily afterwards. Oxymuriatic gas continued the chief subject of the experiments in the laboratory up to the end of February in the following year.

This year Davy was invited to deliver a course of lectures on Electro-Chemical Science, and another course of six lectures on the Application of Chemistry to Agriculture, in the new laboratory of the Dublin Society. Having obtained permission as secretary to be absent from the meetings of the Royal Society, he commenced his course on November 8 and finished it on the 29th, and the Society requested his acceptance of 500 guineas.

In 1811 he again delivered two courses, one on the Elements of Chemical Philosophy and the other on Geology. For these he received 750_l._, and Trinity College made him a Doctor of Laws. Such consideration for lectures on this side of the Atlantic sounds fabulous.

He wrote to his mother:

Balina, Ireland, October 24, 1811.

The laboratory in Dublin, which has been enlarged, so as to hold
550 people, will not hold half the persons who desire to hear my
lectures. The 550 tickets issued for the course by the Dublin
Society at two guineas each were all disposed of the first week,
and I am told now that from ten to twenty guineas are offered for a
ticket.

This is merely for your eye; it may please you to know that your
son is not unpopular or useless. Every person here, from the
highest to the lowest, shows me every attention and kindness.

I shall come to see you as soon as I can. I hear with infinite
delight of your health, and I hope Heaven will continue to preserve
and bless a mother who deserves so well of her children.

I am, your very affectionate Son,
H. DAVY.

During 1811 he made the acquaintance of Mrs. Appreece, the daughter and heiress of Charles Carr, of Kelso, and about the end of the year probably he wrote to his mother:

MY DEAR MOTHER,--You possibly may have heard reports of my intended
marriage. Till within the last few days it was mere report. It is,
I trust, now a settled arrangement. I am the happiest of men in the
hope of a union with a woman equally distinguished for virtues,
talent, and accomplishments.

* * * * *

You, I am sure, will sympathise in my happiness. I believe I should
never have married but for this charming woman, whose views and
whose tastes coincide with my own, and who is eminently qualified
to promote my best efforts and objects in life.

I am, your affectionate Son,
H. DAVY.

He wrote to his brother, at that time a medical student at Edinburgh:

MY DEAR JOHN,--Many thanks for your last letter. I have been
very miserable. The lady whom I love best of any human being has
been very ill. She is now well and I am happy. Mrs. Appreece has
consented to marry me, and when the event takes place I shall not
envy kings, princes, or potentates.

I am, my dear Brother, ever most affectionately yours,

H. DAVY.

The Laboratory Note-Book at this time contains very little work.

On February 21, 1811, he had a paper read to the Royal Society on a ‘Combination of Oxymuriatic Gas and Oxygen Gas, called Euchlorine.’

In July the action of chlorine on carbonic oxide, exposed for hours to bright sunshine, was examined. He wrote, ‘The new gas seems to consist of equal volumes of chlorine and carbonic oxide condensed to one volume.’

On August 7 Davy wrote in the Laboratory Book, ‘To get nitrous oxide, nitrous gas, and very pure chlorine for experiments. To try to decompose nitrogen or to combine it with _chlorine_.’

On the 10th the exposure to the light had been continued two days without result.

In the middle of August he experimented on the action of potassium on silicated fluoric gas.

From September 2 to December 20 there are no entries in the Laboratory Book. That day--the first after his return from Ireland--there are experiments on the electrolization of water.

Early in the following year Sir Joseph Banks wrote to Sir George Staunton (in China):

* * * * *

We are going on here as usual, but I think the taste for science
is on the increase. The Royal Society has been well supplied with
papers, and continues to be so. Davy, our secretary, is said to be
on the point of marrying a rich and handsome widow, who has fallen
in love with science and marries him in order to obtain a footing
in the academic groves; her name is Apreece, the daughter of Mr.
Carr, who made a fortune in India, and the niece of Dr. Carr, of
Northampton. If this takes place, it will give to science a kind of
new éclat; we want nothing so much as the countenance of the ladies
to increase our popularity.

Very little laboratory work was done in 1812. It appears from Davy’s notes that a few experiments on euchlorine were made in January. In February he was again working on sulphur and phosphorus and chlorine. In March he was experimenting on borum with oxygen, and with chlorine.

In August an experiment was made to ascertain whether there is, according to the received belief, a neutral part in the voltaic circle.

The battery consisted of forty double plates, thus arranged: Each trough, excepting the end ones, was separately connected with a glassful of mercury by polished copper wire, and each pair of glasses was connected by very fine polished iron wire.

The effects took place at the moment of contact at all the wires, so that there could have been no _neutral point_.

For the last time, after innumerable failures, he returned to the decomposition of nitrogen.

On August 13 ‘experiment very cautiously made of the action of potassium on nitrogene. Light green when mercury is employed, red when potassium.’

On October 23 the Laboratory Book says:

‘A series of experiments to attempt to decompose hydrofluoric acid, and to ascertain the constitution of the _fluoric combinations_.

‘1. To obtain pure hydrofluoric acid.

‘2. To obtain silicofluoric acid gas, and to decompose it by potassium and by potash, and to ascertain the quantity of fluate of lime they will give.

‘3. To make pure prussic acid.

‘4. To act upon pure prussic acid by chlorine.’

On November 5 a new detonating compound was formed; this was the chloride of nitrogen.

This year Davy gave his last course of lectures on Chemical Philosophy at the Royal Institution.

An account of four of these lectures ‘was taken off from notes by Mr. Faraday.’ The subjects were Radiant Matter, Chlorine, Simple Inflammables, and Metals. After the report of each lecture he gave the experiments as a sequel, illustrated with drawings; the whole made a small quarto of 386 pages, with an index of twenty-five pages. The volume was bound by Mr. Faraday, and was sent to Davy as an evidence of Faraday’s ‘knowledge, diligence, and order,’ when he asked for an engagement at the Royal Institution.

Davy gave the lecture on Radiant Matter on February 29. He said, ‘With respect to radiant or ethereal substances all our knowledge of it is obtained from the effect it produces on us and terrestrial bodies when in motion.

‘In our consideration of this subject it will be essentially necessary that we distinguish between knowledge and speculation. These terms in their meaning are palpably different, but yet have been intermixed and _combined_ together in a very singular manner. The French chemists in particular speak of the materiality of heat, and of the nature of the compounds it forms, as confidently and as fluently as if they had undeniably proved it to be a body. They have blended their knowledge with speculation, and formed a theory that is very possibly untrue. The most eminent phenomena of radiation are to be observed in light.’

And then he passed on to the laws of light and dwelt on Herschel’s discovery that the heating power of red rays was to the green as fifty-five to sixteen, and that he had himself found the thermometer rose still higher beyond the red, and that heating rays are less refrangible than light rays; then he showed a wire heated by the voltaic battery in air and in vacuo, and said that he had proved ‘that the radiating power is three times as strong in an exhausted receiver as in the open air,’ and, ‘fully proves that radiation is not caused by undulations in the atmosphere. It is strongest when no atmosphere is present.’ He ends his account of the effects of radiant heat thus: ‘Were it not for this terrestrial radiation of earthly bodies, the heat would accumulate from the rays of the sun until at last the whole world would be uninhabitable.

‘But, besides the effects produced by the two species of radiant matter--radiant light and radiant heat--there are other effects--chemical effects--that take place caused by the action of some radiant matter that comes to us from the sun, perhaps a single substance that, independent of light and heat, causes effects by its own power.’ And then he showed an experiment of chlorine and hydrogen exposed to light.

He says, ‘There is a very singular analogy that exists between the rays at the violet end of the spectrum, hydrogen gas, and the negative pole of the voltaic battery; and opposed to it stands the analogy of the rays at the red end of the spectrum to positive electricity; they produce opposite effects to the first-mentioned arrangement, but act similar to each other.

‘If that sublime idea of the ancients that there is only one species of matter in the universe, and that its different properties depend on the difference of size, shape and other qualities should be confirmed, it would simplify the science in a most eminent degree, and at the same time it would raise it to the acme of perfection.’

Opposing the view that oxygen gas contained light combined with it, and gave light out in oxidation, he contrasted slowly oxidised iron with an iron turning burnt in oxygen.

‘When the laws which govern in chemical science are fully known, there is no doubt it will become a much more simple science. It cannot fail to be so, since then it will be complete. Already it is one of the most useful of the whole circle to man, and when in its utmost state of improvement it will be one of the most sublime. It will, I have no doubt, connect mechanical and chemical sciences together; it will concentrate them into one and in that one comprehend the whole universe.

‘The first step to truth is the confession of ignorance. No man could have made the immortal discoveries of Newton unless he had first thrown up the ridiculous doctrines of Des Cartes. To attend to our errors and own them, to sacrifice all selfishness to the science, not to support errors for the sake of vanity, ought to be the leading precepts of a philosopher. He should turn his endeavour to the advancement of science and not to the increase of his reputation. Let him fix steps for others to rise on, and he does more real good to science than if he had spent years in controversy on an equivocal point. Let him turn his thoughts to general views and try to contain the whole science in his grasp; he will then be calculated to arrange it, improve it, and reform it and place it in that order which tends so materially to its advancement.’

His lecture on Chlorine was given on Saturday, March 14; the previous week he had given a lecture on Oxygen, which was not reported by Faraday.

‘I will demonstrate what I affirm in a positive and satisfactory manner.

‘Accustomed for years to consider the chemical principles of the French School of Physical Sciences as correct, I had adopted them and put faith in them until they became prejudices, and I even felt unwilling to give them up when my judgment was fully convinced by experiment that they were erroneous. I know that this is the case in some degree with almost every person; he is unwilling to believe that he is wrong, and therefore feels averse to adopt what is right when it opposes his principles.

‘Pelletier died from inhaling this gas (chlorine). It supports combustion of a taper [experiment]; it does not contain oxygen.’ He showed by experiment that pure dry chlorine and hydrogen, when exploded, caused no moisture; no water was formed. This was the synthetical proof. Decomposition of muriatic acid gas by potassium was shown as the analytical proof. Compounds with phosphorus, ammonia, and sulphur all free from oxygen. ‘Oxygen does combine with chlorine. I have ventured to name the compound euchlorine; it is of a very bright yellow green colour. Names should represent things, not opinions, for in the last case they often tend to misrepresent and mislead.

‘As chlorine contained no oxygen, it became an inquiry well worth investigation to ascertain the part which chlorine acted in bleaching. It decomposes water and forms hydrochloric acid.’

‘Had Mr. Berthollet obtained oxygen from chlorine there would have been no error in his theory, but by not attending to the minute circumstances of his experiment, by not ascertaining that the water present acted no part and was not decomposed, he fell into an error, and of course all the conclusions he drew were false and erroneous. Nothing should be allowed but what can be proved by experiment, and nothing should be taken for granted upon analogy or supposition.’

Faraday concludes this lecture thus: ‘Mr. Davy now proceeded to comment and make observations on the former theory of chlorine gas. Here I was unable to follow him. The plan which I pursue in taking of notes is convenient and sufficient with respect to the theoretical and also the practical part of the lecture, but for the embellishments and ornaments of it it will not answer. Mr. Davy’s language at those times is so superior (and indeed throughout the whole course of the lecture) that then I am infinitely below him and am incapable of following him even in an humble style. Therefore I shall not attempt it; it will be sufficient to give a kind of contents of it.

‘He said that hypotheses should not be considered as facts and built upon accordingly. Nevertheless, if cautiously pursued, they might lead to mature fruit. That nothing should be taken for granted unless proved. By considering oxygen as contained in chlorine the whole chemical world had been wrapped in error respecting that body for more than one-third of a century.

‘He noticed that all the truly great scientific men were possessed of great humility and diffidence of their own opinions and powers. He spoke of Scheele, the discoverer of chlorine; observed that he possessed a truly philosophical spirit, gave up his opinions when he supposed them to be erroneous, and without hesitation or reluctance adopted those of others which he considered more correct; admired his spirit and recommended it to all philosophers; compared it to corn, which looked but simple and insignificant in blossom and asked for little praise, yet was the support of man.’

In this lecture Faraday gives the details of twenty experiments.

On April 8 Professor Davy lectured on Simple Inflammable Bodies. ‘Their number, excepting the metals, is six, which unite with oxygen and chlorine, the subjects of the two last lectures.’ He showed a jet of oxygen burning in hydrogen, and said, ‘In the burning of tallow, wax, oil, and wood it is the hydrogen of their bodies that causes the flame; though in most cases it is also combined with carbon, yet it is the hydrogen that produces the flame....

‘I have here a bladder filled with nitrous oxide gas; I will breathe it once or twice, but not so far as to incapacitate me from continuing the lecture. It produces a very pleasing sensation (far superior to the most exquisite liquors, such as champagne), and I have no doubt that if I were to continue it a few minutes longer I should make a very interesting exhibition to the company; but I would rather be excused....

‘If we suppose that the diamond is pure carbon, and is therefore the same as charcoal, we have a very strong presumptive reason to suppose that all matter is alike in all substances. If substances so opposite and so different as charcoal and diamond are in reality the same kind of matter, then the difference in other bodies is no proof that they also are not of the same kind of matter; and this would lead us to suppose that there is but one matter in nature, and that the difference in different bodies is owing to variety in the distance of the particles, to shape, and to size....

‘In conclusion several of these six simple combustibles I suspect to be compounds, and perhaps their nature may shortly be discovered....

‘What gives a strong colour to the idea of the compound nature of nitrogen is the quantity of it that can be obtained from animal bodies, whereas they imbibe none, they combine with none.

‘Sulphur and phosphorus both appear to be compound bodies when they are subjected to the power of a voltaic battery. A great quantity of hydrogen gas is evolved, so that it appears hydrogen is one of their constituent parts....

‘Whether these bodies are compound or not, they are objects of new research; they present new fields for the great, the industrious, the scientific, and the penetrating mind. Our horizon extends the higher we rise. The result of future inquiries will probably lay a foundation on which future ages and future generations may erect an edifice that will reach from earth to heaven.’

In this lecture Faraday noted twenty-two experiments.

The next day, April 9, Davy was knighted by the Prince Regent.

On April 10 Sir Humphry Davy gave his last lecture at the Royal Institution; it was on the Metals.

‘All the volatile metals burn with flame, and all those that are not volatile with sparks....

‘These, with the metals of the alkalies and the alkaline earths which I have had the good fortune to discover, make up the number to about forty.’

He shewed the mode of obtaining alkaline metals by voltaic decomposition; and earths by potassium.

The mode of obtaining the alkaline metals by chemical action alone was shown, but the experiment was not made. A quantity of potassium from common potash by iron was on the table.

‘The combustion of metals is according to their electricity, those containing the most electricity burning with the most energy. All those metals that are positive to others are also more inflammable than those others, and burn more readily....

‘That the metals of the earths and alkalies cannot exist at the surface of our globe we are well assured, but they may exist in the interior, and if so they will offer a very complete and a very probable solution of the phenomena of earthquakes and volcanoes; and perhaps, considered thus, they may lay the foundation of a new and perfect system of geology.

‘We have here a small volcano formed of clay, &c., in the shape of a mountain, and having two or three pieces of the alkaline metals introduced here and there. Now by adding a little water to this volcano I shall be able to inflame it and cause it to burn briskly....

‘Meteors consist of alkaline metals and iron; the iron burns last if it be burnt at all.

‘What I conceive is, that there are certain bodies that revolve round our earth--a kind of satellites--and are the same with respect to our globe that comets are to the sun. Their orbits are ellipses, whose longer diameters, like those of the comets, far exceed their shorter ones. They must move with very great velocity to counteract the attraction of the earth....’

Regarding transmutation of metals he said ‘the beginning was deceit, the progress falsehood, and the end beggary, said Lemery.’

‘It was supposed till lately that the fixed alkalies were simple bodies, but I have had the good fortune to prove them compounds; and that pure potash should contain a metal, oxygen, and water is not more probable than that the metals are compounds, yet it not only is probable but it is possible, and in reality is so....

‘From the mercurial amalgam and from the quantity of hydrogen given out by metals when exposed to the action of a vigorous voltaic battery, either this hydrogen is combined with the metal or it is one of its constituent parts....

‘If, then, we suppose that hydrogen constitutes a part of all metals, they will be compounds of it and a base. The hydrogen will give them their genuine characters and make them metals, and their base will bestow on them their own peculiar properties.

‘I should wish particularly on this point to be understood rightly. I am not an advocate for alchemy and its attendant frauds; that will appear from the tenor of my discourse; but I conceive it to be a noble and glorious object to follow up the paths trod by those chemists who wish for the improvement of science to ascertain the compound nature of metals. It is a subject well worthy of pursuit, and whenever the discovery is made it will confer immortal honour on the discoverer, the age, and the country that it is made in.’

Faraday then says, ‘Having thus given the general character of the metals, Sir H. Davy proceeded to make a few observations on the connection of science with the other parts of polished and social life. Here it would be improper for me to follow him. I should merely injure and destroy the beautiful, the sublime observations that fell from his lips. He spoke in the most energetic and luminous manner of the advancement of the arts and sciences, of the connection that had always existed between them and other parts of a nation’s economy. He noticed the peculiar congeries of great men in all departments of life that generally appeared together, noticed Anaximander, Anaximenes, Socrates, Newton, Bacon, Elizabeth, &c., but, by an unaccountable omission, forgot himself, though I will venture to say no one else present did.

‘During the whole of these observations his delivery was easy, his diction elegant, his tone good, and his sentiments sublime.’

Faraday ends his volume with the notes of eighteen experiments that were made in this lecture.

The same day Davy wrote to his brother. It was the eve of his wedding.

Friday, April 10, 1812.

MY DEAR BROTHER,--You will have excused me for not writing to
you on subjects of science. I have been absorbed by arrangements
on which the happiness of my future life depends. Before you
receive this these arrangements will, I trust, be settled, and in
a few weeks I shall be able to return to my habits of study and
scientific research. I am going to be married to-morrow, and I have
a fair prospect of happiness with the most amiable and intellectual
woman I have ever known.

The Prince Regent, unsolicited by me or by any of my intimate
friends, was pleased to confer the honour of knighthood on me at
the last levée. This distinction has not often been bestowed on
scientific men, but I am proud of it, as the greatest of human
geniuses bore it; and it is at least a proof that the world has not
overlooked my humble efforts in the cause of science.

* * * * *

I am, my dear Brother, most affectionately yours,
H. DAVY.

On June 12 he published his ‘Elements of Chemical Philosophy.’ It is dedicated to Lady Davy, ‘as a pledge that he shall continue to pursue science with unabated ardour.’

Dr. Thomas Young, in the ‘Quarterly Review’ for September 1812, enables us to see what was thought of Sir H. Davy and of his book at this time.

‘In attempting a review of this work we cannot avoid professing that we are far from entertaining the impression of sitting down as competent judges to decide upon the merits or demerits of the author; on this point the public voice, not only within our own islands, but wherever science is cultivated, has already pronounced too definite a sentence to be weakened or confirmed by anything that we can suggest of exception or approbation. Our humble labours on such an occasion must be much more analytical and historical than critical; at the same time we are too well acquainted with the author’s candour to suppress any remark which may occur to us as tending to correction or improvement. It has most assuredly fallen to the lot of no one individual to contribute to the progress of chemical knowledge by discoveries so numerous and important as those which have been made by Sir Humphry Davy; and, with regard to mere experimental investigation, we do not hesitate to rank his researches as more splendidly successful than any which have ever before illustrated the physical sciences in any of their departments. We are aware that the “Optics” of Newton will immediately occur to our readers as an exception; but, without attempting to convince those who may differ from us on this point, we are disposed to abide by the opinion that for a series of well-devised experiments and brilliant discoveries the contents of Davy’s “Bakerian Lectures” are as much superior to those of Newton’s “Optics” as the “Principia” are to those or to any other human work for the accurate and refined application of a sublime and simple theory to the most intricate and apparently anomalous results derived from previous observation.

* * * * *

‘Until the year 1806 Sir Humphry Davy had been remarkable for the industrious and ingenious application of those means of experiment only which had been long known to chemists. He had acquired at a very early period of his life a well-established celebrity among men of science throughout Europe by the originality and accuracy of his researches, and at the same time the fluent and impressive delivery of his lectures had obtained him the most flattering marks of approbation from the public of the metropolis. But it was in the summer of that year that, in repeating some electro-chemical experiments of very doubtful authority (the production of acid and alkali by the decomposition of water), he was led into a new train of reasoning and investigation, which enabled him to demonstrate the important laws of the connection between the electrical affections of bodies and their chemical powers. This was his first great discovery.... Our author’s next great step was the decomposition of the alkalies, which he effected the succeeding year; and this, though less interesting and important with regard to the fundamental theory of the science, was more brilliant and imposing from its capability of being exhibited in a visible, tangible form. The third striking feature which distinguishes the system advanced in the present work is the assertion of the existence of at least two empyreal principles--oxygen and the elastic fluid called the oxymuriatic acid gas (chlorine)....

‘A fourth peculiarity, which, however, is less exclusively and originally a doctrine of Sir Humphry Davy, is the theory of the simplicity of the proportions in which all bodies combine--a theory the explicit illustration and general and minute application of which the science is principally indebted to our countryman Mr. Dalton.’

How far later discoveries have advanced our knowledge can be seen in the strange words, as they now sound, which Dr. Young uses when he mentions the first researches of Davy.

‘Certain bodies which attract each other chemically, and combine when their particles have freedom of motion, when brought into contact still preserving their aggregation, exhibit what may be called electrical polarities, and by certain combinations these polarities may be highly exalted; and in this case they become subservient to chemical decompositions, and, by means of chemical arrangements, the constituent parts of bodies are separated in uniform order and in definite proportions.’

* * * * *

The review then gives the account of the discovery of potassium, sodium, barium, strontium, magnesium, aluminum, glycinium, zirconium, silicium, and itrium and boron.

On the subject of oxymuriatic acid gas Dr. Young says ‘we cannot help thinking his tone somewhat more decisive than the present state of the investigation altogether authorises,’ and he strongly objects to Davy’s terminology; which never was adopted by chemists.

As no table of the proportional weights of chemical substances entering into combination is to be found in Sir H. Davy’s work, Dr. Young says he took the liberty of inserting one formed from Davy’s numbers and from the experiments of Berzelius and Richter.

He thus ended his review, ‘The character of Sir Humphry Davy’s researches has always been that of the most interesting originality, and we have certainly no reason to complain that he has in his experiments very commonly forsaken the beaten path.

* * * * *

‘With all its excellences this work must be allowed to bear no inconsiderable marks of haste, and we would easily have conjectured, even if the author had not expressly told us so in his dedication, that the period employed on it “has been the happiest of his life.” In that and in every other happiness which may have befallen him we shall ever most sincerely rejoice; nor shall we think the public will have any reason to reproach him with having done too little for science, even if he should fail at any future time in his avowed resolution of pursuing it “with unabated ardour;” that he has not yet so failed is become from a late accident a matter of public notoriety, and if we may expect perseverance to be at all commensurate to success, we have no reason to be apprehensive of his passing any part of his life in inactivity.

‘The style and manner of this work are nearly the same with those of the author’s lectures delivered in the theatre of the Royal Institution. They have been much admired by some of the most competent judges of good language and good taste, and it has been remarked that Davy was born a poet, and has only become a chemist by accident. Certainly the situation in which he was placed induced him to cultivate an ornamented and popular style of expression and embellishment, and what was encouraged by temporary motives has become natural to him from habit. Hence have arisen a multitude of sentimental reflections and appeals to the feelings, which many will think beauties and some only prettinesses; nor is it necessary for us to decide in which of the two classes of readers we wish ourselves to be arranged, conceiving that in matters so indifferent to the immediate object of the work a great latitude may be allowed to the diversity of taste and opinion.’

On June 18 Davy sent a paper to the Royal Society on ‘Some Combinations of Phosphorus and Sulphur,’ and in July two other papers--‘Further Observations on Chloride of Nitrogen; and on Fluorine and Hydrofluoric Acid.’

Late in August he wrote to a friend, ‘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.’

On October 14, from Edinburgh, he wrote to Mr. Children:

‘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.’

On October 24 he writes, ‘On Wednesday we are to have a meeting at the Institution, to try to make this compound of azote and chlorine.’

On November 5 a letter was read at the Royal Society from Davy to Sir Joseph Banks on this compound, which had been formed by exposing chlorine to a solution of nitrate of ammonia. During his investigation the substance exploded in a tube, and he received a severe wound in the eye.

On November 16 he wrote to his brother, ‘It is not safe to experiment upon a globule larger than a pin’s head. I have been severely wounded by a piece scarcely bigger.’

In January 1813 he had another severe attack of inflammation in the wounded eye, and it was not perfectly well till April.

On April 4 he wrote to his brother, ‘I am now quite recovered, and Jane is very well, and we have both enjoyed the last month in London. I have been hard at work (on fluorine). We have now a triad of supporters of combustion.

‘I have just finished printing my “Agricultural Lectures.”’

Soon after he again wrote to his brother:

I communicated to you in a former letter my plans as far as they
were matured. I have neither given up the Institution nor am I
going to France, and, wherever I am, I shall continue to labour
in the cause of science with a zeal not diminished by increase of
happiness and (with respect to the world) increased independence.

I have just finished the first part of my ‘Chemistry’ to my own
satisfaction, and I am going to publish my ‘Agricultural Lectures,’
for which I am to get 1,000 guineas for the copyright and fifty
guineas for each edition, which seems a fair price. As I shall see
you so soon I shall not write about any matters of science.

I was appointed professor (honorary) to the Institution at the last
meeting (April 5). I do not pledge myself to give lectures. Brande
gives twelve.

If I lecture it will be on some new series of discoveries, should
it be my fortune to make them, and I give up the routine of
lecturing merely that I may have more time to pursue original
inquiries and forward more the great objects of science. This has
been for some time my intention, and it has been hastened by my
marriage.

I shall have great pleasure in making you acquainted with Lady D.
She is a noble creature (if I may be permitted so to speak of a
wife) and every day adds to my contentment by the powers of her
understanding and her amiable and delightful tones of feeling. God
bless you!

Believe me to be your affectionate brother,
H. DAVY.

In the minutes of the monthly meetings of members of the Royal Institution, April 5, 1813, it is stated that Sir H. Davy rose and begged leave to resign his situation of Professor of Chemistry; ‘but he by no means wished to give up his connection with the Royal Institution, as he should ever be happy to communicate his researches in the first instance to the Institution in the way he did in the presence of the members last Wednesday (on hydrofluoric acid), and to do all in his power to promote the interest and success of this Institution.’

Earl Spencer moved ‘that the thanks of this meeting be returned to Sir H. Davy for the inestimable services rendered by him to the Royal Institution, and that, in order more strongly to mark the high sense entertained by this meeting of the merits of Sir H. Davy, he be elected Honorary Professor of Chemistry.’

Mr. Brande was then nominated Professor of Chemistry, with a salary of 200_l._ per annum.

In October Sir H. Davy went abroad with Mr. Faraday.

In May 1815 he came back, and Faraday was re-engaged as the assistant in the laboratory of the Royal Institution. Whilst abroad he had sent as many as seven papers to the Royal Society--on ‘Fluoric Acid Compounds and Hydrogen Acids.’ Two papers on ‘Iodine,’ on ‘Combustion of the Diamond,’ on ‘Ancient Colours,’ on a ‘Solid Compound of Iodine and Oxygen,’ on ‘Hyperoxy-Muriates.’

When he returned he probably intended to make greater discoveries in chemistry during the following ten years than he had made during the fifteen years that he had been at the Institution. He was in the prime of life. He had won the highest rank as an original inquirer. He had a love of research which, in spite of his marriage, his wealth, and ultimately his ill health, never ceased until his early death. He had Faraday as his assistant, and he soon found a subject more fruitful than the composition of nitrogen, which had so long baffled his genius.

Many of the details of his work in the laboratory until his last experiment on the diffusion of gases, in February 1826, are to be found in the ‘Life of Faraday.’ It will be sufficient to give here a statement of the original researches which he communicated to the Royal Society.

In November 1815 and January 1816 his papers on Fire-damp were read. He then worked upon flame, and in January 1817 his researches on flame and his splendid invention of the Davy Lamp were laid before the Royal Society. At this time the popular reputation of Davy reached its climax, and, looking back, we can now see that his life should have ended here; he was then only 38 years old. He was presented with a service of plate as a token of his invaluable invention by the coal owners of the Tyne and Wear. He bequeathed this to the Royal Society for the foundation of a medal, to be given yearly to the chemist who made the greatest discovery. This prize should be looked on as a lasting memorial of the countless lives which Davy and other chemists, by the application of their scientific researches, have preserved.

Year after year, from 1817 to 1826, Davy communicated new investigations to the Royal Society. He worked on chlorine, on phosphorus, on mists. He went abroad again, and he tried chemically to unfold the Herculanean papyri. He returned in 1820, and was elected President of the Royal Society after the death of Sir Joseph Banks. Then he worked on magnetic phenomena produced by electricity, on electric phenomena in vacuo, on water in the cavities of crystals, on new phenomena of electro-magnetism. He became jealous of the discoveries of Faraday, and he sent a paper to the Royal Society on the ‘Application of Liquids Formed by the Condensation of Gases as Mechanical Agents.’

In 1823 he began to work on the defence of the copper sheathing of ships, and in 1824 he had two papers published on this subject. He went in a Government steamboat to Norway, Sweden, and Denmark for the purpose of trying the influence of motion on his protectors. He had already suffered for a year at this time from ill health. In 1825 his paper on the ‘Preservation of Metals by Electrochemistry’ was published. In practice his plan failed, and he was too ill to bear lightly the disappointment of his expectations. In 1826 he had a paper read on the ‘Relations of Electrical and Chemical Changes.’ It contained but little new matter. On November 30 he was elected President of the Royal Society for the last time. He was dangerously ill on the day of election.

In the middle of December 1826 he was struck with paralysis of the right side.

With the restlessness of disease on January 22, about a month after his attack, he set out for Italy. He had the worst possible journey across Mont Cenis, and, after being three weeks at Ravenna, in the middle of March he wrote to Mr. Poole:

I am, thank God, better, but still very weak and wholly unfit for
any kind of business and study. I have, however, considerably
recovered the use of all the limbs that were affected, and, as
my amendment has been slow and gradual, I hope in time it may be
complete. But I am leading the life of an anchorite, obliged to
abstain from flesh, wine, business, study, experiments, and all
things that I love; but this discipline is salutary, and, for the
sake of being able to do something more for science, and I hope
for humanity, I submit to it, believing that the Great Source of
intellectual being so wills it for good.

One of the last thoughts in his note-book, written at Ravenna, shows his mind:

‘Our _real knowledge_ is but to be sure that we know nothing, and I can but doubt if this be a curse or blessing. Those who hope, trust, and believe are surely happier far than those who doubt; and the submissive child, who of his father’s goodness is secure, is far more blessed than the froward one, who sets himself against his powerful will, which, after all his struggles and vain efforts, he must at last obey, rebelling against the love which would have made him happy. Is not this the history of man?--of that bright and beauteous garden where in innocence and ignorance he lived and loved till the false taste of knowledge made him wretched and he knew that he must die. And is not this the glory and the consummation of the Christian faith, which gives him back his innocence, his hopes, his confidence in God, which through his life still gilds the future with a golden blessing of an expected immortality? Man fell in Adam; knowledge was his bane; man rose in Christ, recovering his ignorance or substituting hope for what was doubt.’

Four or five days before he left Ravenna he wrote, April 6, ‘Did not shoot, but returned thanks to the Great Cause of all being for all His mercies to me, an undeserving and often ungrateful creature, but now most grateful. May I become better and more grateful and more humble-minded every day!’