Faraday As A Discoverer
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John Tyndall >> Faraday As A Discoverer
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10 Faraday As A Discoverer, by John Tyndall
Contents.
Preface.
Chapter 1.
Parentage: introduction to the royal institution:
earliest experiments: first royal society paper: marriage.
Chapter 2.
Early researches: magnetic rotations: liquefaction of gases:
heavy glass: Charles Anderson: contributions to physics.
Chapter 3.
Discovery of Magneto-electricity: Explanation of Argo's magnetism
of rotation: Terrestrial magneto-electric induction:
The extra current.
Chapter 4.
Points of Character.
Chapter 5.
Identity of electricities; first researches on electro-chemistry.
Chapter 6.
Laws of electro-chemical decomposition.
Chapter 7.
Origin of power in the voltaic pile.
Chapter 8.
Researches on frictional electricity: induction: conduction:
specific inductive capacity: theory of contiguous particles.
Chapter 9.
Rest needed--visit to Switzerland.
Chapter 10.
Magnetization of light.
Chapter 11.
Discovery of diamagnetism--researches on magne-crystallic action.
Chapter 12.
Magnetism of flame and gases--atmospheric magnetism.
Chapter 13.
Speculations: nature of matter: lines of force.
Chapter 14.
Unity and convertibility of natural forces: theory of the
electric current.
Chapter 15.
Summary.
Chapter 16.
Illustrations of Character.
Preface to the fifth edition.
Daily and weekly, from all parts of the world, I receive publications
bearing upon the practical applications of electricity. This great
movement, the ultimate outcome of which is not to be foreseen, had
its origin in the discoveries made by Michael Faraday, sixty-two
years ago. From these discoveries have sprung applications of the
telephone order, together with various forms of the electric
telegraph. From them have sprung the extraordinary advances made in
electrical illumination. Faraday could have had but an imperfect
notion of the expansions of which his discoveries were capable.
Still he had a vivid and strong imagination, and I do not doubt that
he saw possibilities which did not disclose themselves to the
general scientific mind. He knew that his discoveries had their
practical side, but he steadfastly resisted the seductions of this
side, applying himself to the development of principles; being well
aware that the practical question would receive due development
hereafter.
During my sojourn in Switzerland this year, I read through the
proofs of this new edition, and by my reading was confirmed in the
conviction that the book ought not to be suffered to go out of
print. The memoir was written under great pressure, but I am not
ashamed of it as it stands. Glimpses of Faraday's character and
gleams of his discoveries are there to be found which will be of
interest to humanity to the end of time.
John Tyndall.
Hind Head,
December, 1893.
[Note.--It was, I believe, my husband's intention to substitute
this Preface, written a few days before his death, for all former
Prefaces. As, however, he had not the opportunity of revising the
old prefatory pages himself, they have been allowed to remain just
as they stood in the last edition.
Louisa C. Tyndall.]
Preface to the fourth edition.
When consulted a short time ago as to the republication of 'Faraday
as a Discoverer,' it seemed to me that the labours, and points of
character, of so great a worker and so good a man should not be
allowed to vanish from the public eye. I therefore willingly fell
in with the proposal of my Publishers to issue a new edition of the
little book.
Royal Institution,
February, 1884.
Preface to the second edition.
The experimental researches of Faraday are so voluminous,
their descriptions are so detailed, and their wealth of illustration
is so great, as to render it a heavy labour to master them.
The multiplication of proofs, necessary and interesting when the new
truths had to be established, are however less needful now when
these truths have become household words in science. I have
therefore tried in the following pages to compress the body, without
injury to the spirit, of these imperishable investigations, and to
present them in a form which should be convenient and useful to the
student of the present day.
While I write, the volumes of the Life of Faraday by Dr. Bence
Jones have reached my hands. To them the reader must refer for an
account of Faraday's private relations. A hasty glance at the work
shows me that the reverent devotion of the biographer has turned to
admirable account the materials at his command.
The work of Dr. Bence Jones enables me to correct a statement
regarding Wollaston's and Faraday's respective relations to the
discovery of Magnetic Rotation. Wollaston's idea was to make the
wire carrying a current rotate round its own axis: an idea
afterwards realised by the celebrated Ampere. Faraday's discovery
was to make the wire carrying the current revolve round the pole of
a magnet and the reverse.
John Tyndall.
Royal Institution:
December, 1869.
FARADAY AS A DISCOVERER.
Chapter 1.
Parentage: introduction to the royal institution:
earliest experiments: first royal society paper: marriage.
It has been thought desirable to give you and the world some image
of MICHAEL FARADAY, as a scientific investigator and discoverer.
The attempt to respond to this desire has been to me a labour of
difficulty, if also a labour of love. For however well acquainted
I may be with the researches and discoveries of that great
master--however numerous the illustrations which occur to me of the
loftiness of Faraday's character and the beauty of his life--still
to grasp him and his researches as a whole; to seize upon the ideas
which guided him, and connected them; to gain entrance into that
strong and active brain, and read from it the riddle of the world--
this is a work not easy of performance, and all but impossible amid
the distraction of duties of another kind. That I should at one
period or another speak to you regarding Faraday and his work is
natural, if not inevitable; but I did not expect to be called upon
to speak so soon. Still the bare suggestion that this is the fit
and proper time for speech sent me immediately to my task: from it
I have returned with such results as I could gather, and also with
the wish that those results were more worthy than they are of the
greatness of my theme.
It is not my intention to lay before you a life of Faraday in the
ordinary acceptation of the term. The duty I have to perform is
to give you some notion of what he has done in the world; dwelling
incidentally on the spirit in which his work was executed,
and introducing such personal traits as may be necessary to the
completion of your picture of the philosopher, though by no means
adequate to give you a complete idea of the man.
The newspapers have already informed you that Michael Faraday was
born at Newington Butts, on September 22, 1791, and that he died at
Hampton Court, on August 25, 1867. Believing, as I do, in the
general truth of the doctrine of hereditary transmission--sharing
the opinion of Mr. Carlyle, that 'a really able man never proceeded
from entirely stupid parents'--I once used the privilege of my
intimacy with Mr. Faraday to ask him whether his parents showed any
signs of unusual ability. He could remember none. His father,
I believe, was a great sufferer during the latter years of his life,
and this might have masked whatever intellectual power he possessed.
When thirteen years old, that is to say in 1804, Faraday was
apprenticed to a bookseller and bookbinder in Blandford Street,
Manchester Square: here he spent eight years of his life, after
which he worked as a journeyman elsewhere.
You have also heard the account of Faraday's first contact with the
Royal Institution; that he was introduced by one of the members to
Sir Humphry Davy's last lectures, that he took notes of those
lectures; wrote them fairly out, and sent them to Davy, entreating
him at the same time to enable him to quit trade, which he detested,
and to pursue science, which he loved. Davy was helpful to the young
man, and this should never be forgotten: he at once wrote to
Faraday, and afterwards, when an opportunity occurred, made him his
assistant.[1] Mr. Gassiot has lately favoured me with the following
reminiscence of this time:--
'Clapham Common, Surrey,
'November 28, 1867.
'My Dear Tyndall,--Sir H. Davy was accustomed to call on the late
Mr. Pepys, in the Poultry, on his way to the London Institution, of
which Pepys was one of the original managers; the latter told me
that on one occasion Sir H. Davy, showing him a letter, said:
"Pepys, what am I to do, here is a letter from a young man named
Faraday; he has been attending my lectures, and wants me to give him
employment at the Royal Institution--what can I do?" "Do?" replied
Pepys, "put him to wash bottles; if he is good for anything he will
do it directly, if he refuses he is good for nothing." "No, no,"
replied Davy; "we must try him with something better than that."
The result was, that Davy engaged him to assist in the Laboratory
at weekly wages.
'Davy held the joint office of Professor of Chemistry and Director
of the Laboratory; he ultimately gave up the former to the late
Professor Brande, but he insisted that Faraday should be appointed
Director of the Laboratory, and, as Faraday told me, this enabled
him on subsequent occasions to hold a definite position in the
Institution, in which he was always supported by Davy.
I believe he held that office to the last.
'Believe me, my dear Tyndall, yours truly,
'J. P. Gassiot.
'Dr. Tyndall.'
From a letter written by Faraday himself soon after his appointment
as Davy's assistant, I extract the following account of his
introduction to the Royal Institution:--
'London, Sept. 13, 1813.
'As for myself, I am absent (from home) nearly day and night, except
occasional calls, and it is likely shall shortly be absent entirely,
but this (having nothing more to say, and at the request of my
mother) I will explain to you. I was formerly a bookseller and
binder, but am now turned philosopher,[2] which happened thus:--
Whilst an apprentice, I, for amusement, learnt a little chemistry
and other parts of philosophy, and felt an eager desire to proceed
in that way further. After being a journeyman for six months,
under a disagreeable master, I gave up my business, and through
the interest of a Sir H. Davy, filled the situation of chemical
assistant to the Royal Institution of Great Britain, in which office
I now remain; and where I am constantly employed in observing the
works of nature, and tracing the manner in which she directs the
order and arrangement of the world. I have lately had proposals
made to me by Sir Humphry Davy to accompany him in his travels
through Europe and Asia, as philosophical assistant. If I go at all
I expect it will be in October next--about the end; and my absence
from home will perhaps be as long as three years. But as yet all is
uncertain.'
This account is supplemented by the following letter, written by
Faraday to his friend De la Rive,[3] on the occasion of the death
of Mrs. Marcet. The letter is dated September 2, 1858:--
'My Dear Friend,--Your subject interested me deeply every way;
for Mrs. Marcet was a good friend to me, as she must have been to
many of the human race. I entered the shop of a bookseller and
bookbinder at the age of thirteen, in the year 1804, remained there
eight years, and during the chief part of my time bound books.
Now it was in those books, in the hours after work, that I found
the beginning of my philosophy.
There were two that especially helped me, the "Encyclopaedia
Britannica," from which I gained my first notions of electricity,
and Mrs. Marcet's "Conversation on Chemistry," which gave me my
foundation in that science.
'Do not suppose that I was a very deep thinker, or was marked as a
precocious person. I was a very lively imaginative person, and
could believe in the "Arabian Nights" as easily as in the
"Encyclopaedia." But facts were important to me, and saved me.
I could trust a fact, and always cross-examined an assertion.
So when I questioned Mrs. Marcet's book by such little experiments
as I could find means to perform, and found it true to the facts as
I could understand them, I felt that I had got hold of an anchor in
chemical knowledge, and clung fast to it. Thence my deep veneration
for Mrs. Marcet--first as one who had conferred great personal good
and pleasure on me; and then as one able to convey the truth and
principle of those boundless fields of knowledge which concern
natural things to the young, untaught, and inquiring mind.
'You may imagine my delight when I came to know Mrs. Marcet
personally; how often I cast my thoughts backward, delighting to
connect the past and the present; how often, when sending a paper
to her as a thank-offering, I thought of my first instructress,
and such like thoughts will remain with me.
'I have some such thoughts even as regards your own father; who was,
I may say, the first who personally at Geneva, and afterwards by
correspondence, encouraged, and by that sustained me.'
Twelve or thirteen years ago Mr. Faraday and myself quitted the
Institution one evening together, to pay a visit to our friend Grove
in Baker Street. He took my arm at the door, and, pressing it to
his side in his warm genial way, said, 'Come, Tyndall, I will now
show you something that will interest you.' We walked northwards,
passed the house of Mr. Babbage, which drew forth a reference to the
famous evening parties once assembled there. We reached Blandford
Street, and after a little looking about he paused before a
stationer's shop, and then went in. On entering the shop, his usual
animation seemed doubled; he looked rapidly at everything it
contained. To the left on entering was a door, through which he
looked down into a little room, with a window in front facing
Blandford Street. Drawing me towards him, he said eagerly,
'Look there, Tyndall, that was my working-place. I bound books in
that little nook.' A respectable-looking woman stood behind the
counter: his conversation with me was too low to be heard by her,
and he now turned to the counter to buy some cards as an excuse for
our being there. He asked the woman her name--her predecessor's
name-- his predecessor's name. 'That won't do,' he said, with
good-humoured impatience; 'who was his predecessor?' 'Mr. Riebau,'
she replied, and immediately added, as if suddenly recollecting
herself, 'He, sir, was the master of Sir Charles Faraday.'
'Nonsense!' he responded, 'there is no such person.' Great was her
delight when I told her the name of her visitor; but she assured me
that as soon as she saw him running about the shop, she felt-though
she did not know why--that it must be 'Sir Charles Faraday.'
Faraday did, as you know, accompany Davy to Rome: he was re-engaged
by the managers of the Royal Institution on May 15, 1815. Here he
made rapid progress in chemistry, and after a time was entrusted
with easy analyses by Davy. In those days the Royal Institution
published 'The Quarterly Journal of Science,' the precursor of our
own 'Proceedings.' Faraday's first contribution to science appeared
in that journal in 1816. It was an analysis of some caustic lime
from Tuscany, which had been sent to Davy by the Duchess of Montrose.
Between this period and 1818 various notes and short papers
were published by Faraday. In 1818 he experimented upon
'Sounding Flames.' Professor Auguste De la Rive had investigated
those sounding flames, and had applied to them an explanation which
completely accounted for a class of sounds discovered by himself,
but did not account for those known to his predecessors. By a few
simple and conclusive experiments, Faraday proved the explanation
insufficient. It is an epoch in the life of a young man when he
finds himself correcting a person of eminence, and in Faraday's
case, where its effect was to develop a modest self-trust, such an
event could not fail to act profitably.
From time to time between 1818 and 1820 Faraday published scientific
notes and notices of minor weight. At this time he was acquiring,
not producing; working hard for his master and storing and
strengthening his own mind. He assisted Mr. Brande in his lectures,
and so quietly, skilfully, and modestly was his work done, that
Mr. Brande's vocation at the time was pronounced 'lecturing on velvet.'
In 1820 Faraday published a chemical paper 'on two new compounds of
chlorine and carbon, and on a new compound of iodine, carbon,
and hydrogen.' This paper was read before the Royal Society on
December 21, 1820, and it was the first of his that was honoured
with a place in the 'Philosophical Transactions.'
On June 12, 1821, he married, and obtained leave to bring his young
wife into his rooms at the Royal Institution. There for forty-six
years they lived together, occupying the suite of apartments which
had been previously in the successive occupancy of Young, Davy, and
Brande. At the time of her marriage Mrs. Faraday was twenty-one
years of age, he being nearly thirty. Regarding this marriage I will
at present limit myself to quoting an entry written in Faraday's own
hand in his book of diplomas, which caught my eye while in his
company some years ago. It ran thus:--
'25th January, 1847.
'Amongst these records and events, I here insert the date of one
which, as a source of honour and happiness, far exceeds all the
rest. We were married on June 12, 1821.
'M. Faraday.'
Then follows the copy of the minutes, dated May 21, 1821, which gave
him additional rooms, and thus enabled him to bring his wife to the
Royal Institution. A feature of Faraday's character which I have
often noticed makes itself apparent in this entry. In his relations
to his wife he added chivalry to affection.
Footnotes to Chapter 1
[1] Here is Davy's recommendation of Faraday, presented to the
managers of the Royal Institution, at a meeting on the 18th of
March, 1813, Charles Hatchett, Esq., in the chair:--
'Sir Humphry Davy has the honour to inform the managers that he has
found a person who is desirous to occupy the situation in the
Institution lately filled by William Payne. His name is Michael
Faraday. He is a youth of twenty-two years of age. As far as Sir H.
Davy has been able to observe or ascertain, he appears well fitted
for the situation. His habits seem good; his disposition active and
cheerful, and his manner intelligent. He is willing to engage
himself on the same terms as given to Mr. Payne at the time of
quitting the Institution.
'Resolved,--That Michael Faraday be engaged to fill the situation
lately occupied by Mr. Payne, on the same terms.'
[2] Faraday loved this word and employed it to the last; he had an
intense dislike to the modern term physicist.
[3] To whom I am indebted for a copy of the original letter.
Chapter 2.
Early researches: magnetic rotations: liquefaction of gases:
heavy glass: Charles Anderson: contributions to physics.
Oersted, in 1820, discovered the action of a voltaic current on a
magnetic needle; and immediately afterwards the splendid intellect
of Ampere succeeded in showing that every magnetic phenomenon then
known might be reduced to the mutual action of electric currents.
The subject occupied all men's thoughts: and in this country
Dr. Wollaston sought to convert the deflection of the needle by the
current into a permanent rotation of the needle round the current.
He also hoped to produce the reciprocal effect of causing a current
to rotate round a magnet. In the early part of 1821, Wollaston
attempted to realise this idea in the presence of Sir Humphry Davy
in the laboratory of the Royal Institution.[1] This was well
calculated to attract Faraday's attention to the subject. He read
much about it; and in the months of July, August, and September he
wrote a 'history of the progress of electro-magnetism,' which he
published in Thomson's 'Annals of Philosophy.' Soon afterwards he
took up the subject of 'Magnetic Rotations,' and on the morning of
Christmas-day, 1821, he called his wife to witness, for the first
time, the revolution of a magnetic needle round an electric current.
Incidental to the 'historic sketch,' he repeated almost all the
experiments there referred to; and these, added to his own
subsequent work, made him practical master of all that was then
known regarding the voltaic current. In 1821, he also touched upon
a subject which subsequently received his closer attention--the
vaporization of mercury at common temperatures; and immediately
afterwards conducted, in company with Mr. Stodart, experiments on
the alloys of steel. He was accustomed in after years to present to
his friends razors formed from one of the alloys then discovered.
During Faraday's hours of liberty from other duties, he took up
subjects of inquiry for himself; and in the spring of 1823, thus
self-prompted, he began the examination of a substance which had
long been regarded as the chemical element chlorine, in a solid
form, but which Sir Humphry Davy, in 1810, had proved to be a
hydrate of chlorine, that is, a compound of chlorine and water.
Faraday first analysed this hydrate, and wrote out an account of its
composition. This account was looked over by Davy, who suggested
the heating of the hydrate under pressure in a sealed glass tube.
This was done. The hydrate fused at a blood-heat, the tube became
filled with a yellow atmosphere, and was afterwards found to contain
two liquid substances. Dr. Paris happened to enter the laboratory
while Faraday was at work. Seeing the oily liquid in his tube, he
rallied the young chemist for his carelessness in employing soiled
vessels. On filing off the end of the tube, its contents exploded
and the oily matter vanished. Early next morning, Dr. Paris
received the following note:--
'Dear Sir,--The oil you noticed yesterday turns out to be
liquid chlorine.
'Yours faithfully,
'M. Faraday.'[2]
The gas had been liquefied by its own pressure. Faraday then tried
compression with a syringe, and succeeded thus in liquefying the gas.
To the published account of this experiment Davy added the following
note:--'In desiring Mr. Faraday to expose the hydrate of chlorine in
a closed glass tube, it occurred to me that one of three things
would happen: that decomposition of water would occur;... or that
the chlorine would separate in a fluid state.' Davy, moreover,
immediately applied the method of self-compressing atmosphere to the
liquefaction of muriatic gas. Faraday continued the experiments,
and succeeded in reducing a number of gases till then deemed permanent
to the liquid condition. In 1844 he returned to the subject, and
considerably expanded its limits. These important investigations
established the fact that gases are but the vapours of liquids
possessing a very low boiling-point, and gave a sure basis to our
views of molecular aggregation. The account of the first investigation
was read before the Royal Society on April 10, 1823, and was
published, in Faraday's name, in the 'Philosophical Transactions.'
The second memoir was sent to the Royal Society on December 19, 1844.
I may add that while he was conducting his first experiments on the
liquefaction of gases, thirteen pieces of glass were on one occasion
driven by an explosion into Faraday's eye.
Some small notices and papers, including the observation that glass
readily changes colour in sunlight, follow here. In 1825 and 1826
Faraday published papers in the 'Philosophical Transactions' on
'new compounds of carbon and hydrogen,' and on 'sulphonaphthalic acid.'
In the former of these papers he announced the discovery of Benzol,
which, in the hands of modern chemists, has become the foundation of
our splendid aniline dyes. But he swerved incessantly from chemistry
into physics; and in 1826 we find him engaged in investigating the
limits of vaporization, and showing, by exceedingly strong and
apparently conclusive arguments, that even in the case of mercury
such a limit exists; much more he conceived it to be certain that
our atmosphere does not contain the vapour of the fixed constituents
of the earth's crust. This question, I may say, is likely to remain
an open one. Dr. Rankine, for example, has lately drawn attention
to the odour of certain metals; whence comes this odour, if it be
not from the vapour of the metal?
In 1825 Faraday became a member of a committee, to which Sir John
Herschel and Mr. Dollond also belonged, appointed by the Royal Society
to examine, and if possible improve, the manufacture of glass for
optical purposes. Their experiments continued till 1829, when the
account of them constituted the subject of a 'Bakerian Lecture.'
This lectureship, founded in 1774 by Henry Baker, Esq., of the
Strand, London, provides that every year a lecture shall be given
before the Royal Society, the sum of four pounds being paid to the
lecturer. The Bakerian Lecture, however, has long since passed from
the region of pay to that of honour, papers of mark only being
chosen for it by the council of the Society. Faraday's first
Bakerian Lecture, 'On the Manufacture of Glass for Optical Purposes,'
was delivered at the close of 1829. It is a most elaborate and
conscientious description of processes, precautions, and results:
the details were so exact and so minute, and the paper consequently
so long, that three successive sittings of the Royal Society were
taken up by the delivery of the lecture.[3] This glass did not turn
out to be of important practical use, but it happened afterwards to
be the foundation of two of Faraday's greatest discoveries.[4]
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