HIS METHOD OF WORKING.
It is on record that when a young aspirant asked Faraday the secret of
his success as a scientific investigator, he replied, "The secret is
comprised in three words--Work, Finish, Publish."
Each of these words, we may be sure, is full of meaning, and will guide
us in a useful inquiry.
Already in the "Story of his Life" we have caught some glimpses of
the philosopher at work in his laboratory; but before looking at him
more closely let us learn from a foreigner with what feelings to enter
a place that is hallowed by so many memories sacred in the history
of science. Professor Schönbein, of Basle, who visited England in
1840, says: "During my stay in London, I once worked with Faraday for
a whole day long in the laboratory of the Royal Institution, and I
cannot forbear to say that this was one of the most enjoyable days
that I ever spent in the British capital. We commenced our day's work
with breakfast; and when that was over, I was supplied with one of the
laboratory dresses of my friend, which, when I was presented in it to
the ladies, gave occasion to no little amusement, as the dimensions of
Faraday are different from those of my precious body.
"To work with a man like Faraday was in itself a great pleasure; but
this pleasure was not a little heightened in doing so in a place where
such grand secrets of nature had been unfolded, the most brilliant
discoveries of the century had been made, and entirely new branches of
knowledge had been brought forth. For the empty intellect circumstances
of this nature are indeed of little special value; but they stand in
quite another relation to our power of imagination and inner nature.
"I do not deny that my surroundings produced in me a very peculiar
feeling; and whilst I trod the floor upon which Davy had once
walked--whilst I availed myself of some instrument which this great
discoverer had himself handled--whilst I stood working at the very
table at which the ever-memorable man sought to solve the most
difficult problems of science, at which Faraday enticed the first
sparks out of the magnet, and discovered the most beautiful laws of
the chemical action of current electricity, I felt myself inwardly
elevated, and believed that I myself experienced something of the
inbreathing of the scientific spirit which formerly ruled there with
such creative power, and which still works on."[18]
The habit of Faraday was to think out carefully beforehand the subject
on which he was working, and to plan his mode of attack. Then, if he
saw that some new piece of apparatus was needed, he would describe it
fully to the instrument maker with a drawing, and it rarely happened
that there was any need of alteration in executing the order. If,
however, the means of experiment existed already, he would give
Anderson a written list of the things he would require, at least a day
before--for Anderson was not to be hurried. When all was ready, he
would descend into the laboratory, give a quick glance round to see
that all was right, take his apron from the drawer, and rub his hands
together as he looked at the preparations made for his work. There must
be no tool on the table but such as he required. As he began, his face
would be exceedingly grave, and during the progress of an experiment
all must be perfectly quiet; but if it was proceeding according to his
wish, he would commence to hum a tune, and sometimes to rock himself
sideways, balancing alternately on either foot. Then, too, he would
often talk to his assistant about the result he was expecting. He would
put away each tool in its own place as soon as done with, or at any
rate when the day's work was over, and he would not unnecessarily take
a thing away from its place: thus, if he wanted a perforated cork,
he would go to the drawer which contained the corks and cork-borers,
make there what he wanted, replace the borers, and shut the drawer. No
bottle was allowed to remain without its stopper; no open glass might
stand for a night without a paper cover; no rubbish was to be left on
the floor; bad smells were to be avoided if possible; and machinery
in motion was not permitted to grate. In working, also, he was very
careful not to employ more force than was wanted to produce the effect.
When his experiments were finished and put away, he would leave the
laboratory, and think further about them upstairs.
This orderliness and this economy of means he not only practised
himself, but he expected them also to be followed by any who worked
with him; and it is from conversation with these that I have been
enabled to give this sketch of his manner of working.[19]
This exactness was also apparent in the accounts he kept with the Royal
Institution and Trinity House, in which he entered every little item of
expenditure with the greatest minuteness of detail.
It was through this lifelong series of experiments that Faraday won his
knowledge and mastered the forces of nature. The rare ingenuity of his
mind was ably seconded by his manipulative skill, while the quickness
of his perceptions was equalled by the calm rapidity of his movements.
He had indeed a passion for experimenting. This peeps out in the
preface to the second edition of his "Chemical Manipulation," where
he writes, "Being intended especially as a book of instruction, no
attempts were made to render it pleasing, otherwise than by rendering
it effectual; for I concluded that, if the work taught clearly what
it was intended to inculcate, the high interest always belonging to
a well-made or successful experiment would be abundantly sufficient
to give it all the requisite charms, and more than enough to make it
valuable in the eyes of those for whom it was designed."
He could scarcely pass a gold leaf electrometer without causing the
leaves to diverge by a sudden flick from his silk handkerchief. I
recollect, too, his meeting me at the entrance to the lecture theatre
at Jermyn Street, when Lyon Playfair was to give the first, or one of
the first lectures ever delivered in the building. "Let us go up here,"
said he, leading me far away from the central table. I asked him why he
chose such an out-of-the-way place. "Oh," he replied, "we shall be able
here to find out what are the acoustic qualities of the room."
The simplicity of the means with which he made his experiments was
often astonishing, and was indeed one of the manifestations of his
genius.
A good instance is thus narrated by Sir Frederick Arrow. "When the
electric light was first exhibited permanently at Dungeness, on 6th
June, 1862, a committee of the Elder Brethren, of which I was one,
accompanied Faraday to observe it. We dined, I think, at Dover, and
embarked in the yacht from there, and were out for some hours watching
it, to Faraday's great delight--(a very fine night)--and especially we
did so from the Varne lightship, about equidistant between it and the
French light of Grisnez, using all our best glasses and photometers
to ascertain the relative value of the lights: and this brings me to
my story. Before we left Dover, Faraday, with his usual bright smile,
in great glee showed me a little common paper box, and said, 'I must
take care of this; it's my special photometer,'--and then, opening
it, produced a lady's ordinary black shawl-pin,--jet, or imitation
perhaps,--and then holding it a little way off the candle, showed me
the image very distinct; and then, putting it a little further off,
placed another candle near it, and the relative distance was shown by
the size of the image. He lent me this afterwards when we were at the
Varne lightship, and it acted admirably; and ever since I have used
one as a very convenient mode of observing, and I never do so but I
think of that night and dear good Faraday, and his genial happy way of
showing how even common things may be made useful." After this Faraday
modified his glass-bead photometer, and he might be seen comparing the
relative intensity of two lights by watching their luminous images
on a bead of black glass, which he had threaded on a string, and was
twirling round so as to resolve the brilliant points into circles of
fainter light; or he fixed the black glass balls on pieces of cork,
and, attaching them to a little wheel, set them spinning for the same
purpose. Some of these beads are preserved by the Trinity House, with
other treasures of a like kind, including a flat piece of solder of an
irregular oval form, turned up at one side so as to form a thumb-rest,
and which served the philosopher as a candlestick to support the
wax-light that he used as a standard. The museum of the Royal
Institution contains a most instructive collection of his experimental
apparatus, including the common electrical machine which he made while
still an apprentice at Riebau's, and the ring of soft iron, with its
twisted coils of wire isolated by calico and tied with common string,
by means of which he first obtained electrical effects from a magnet.
In lecturing to the young he delighted to show how easily apparatus
might be extemporized. Thus, in order to construct an electrical
machine he once inverted a four-legged stool to serve for the stand,
and took a white glass bottle for the cylinder. A cork was fitted into
the mouth of this bottle, and a bung was fastened with sealing-wax to
the other end: into the cork was inserted a handle for rotating the
bottle, and in the centre of the bung was a wooden pivot on which it
turned; while with some stout wire he made crutches on two of the legs
of the stool for the axles of this glass cylinder to work upon. The
silk rubber he held in his hand. A japanned tin tea-canister resting on
a glass tumbler formed the conductor, and the collector was the head of
a toasting fork. With this apparently rough apparatus he exhibited all
the rudimentary experiments in electricity to a large audience.
Wishing to carry home in good condition a flower that had been given
him, he rolled a piece of writing-paper round a cork, tied it tightly
with string, and filled the little tube with water. He had thus a
perfectly efficient bouquet-holder.
A lady, calling on his wife, happened to mention that a needle had been
once broken into her foot, and she did not know whether it had been all
extracted or not. "Oh!" said Faraday, "I will soon tell you that,"--and
taking a finely suspended magnetic needle, he held it close to her
foot, and it dipped to the concealed iron.
On this subject Schönbein has also some good remarks. "The laboratory
of the Institution is indeed efficiently arranged, though anything but
large and elaborately furnished. And yet something extraordinary has
happened in this room for the extension of the limits of knowledge; and
already more has been done in it than in many other institutions where
the greatest luxury in the supply of apparatus prevails, and where
there is the greatest command of money. But when men work with the
creative genius of a Davy, and the intuitive spirit of investigation
and the wealth of ideas of a Faraday, important and great things must
come to pass, even though the appliances at command should be of so
limited a character. For the experimental investigator of nature, it is
especially desirable that, according to the kind of his researches, he
should have at command such and such appliances, that he should possess
a 'philosophical apparatus,' a laboratory, &c.; but for the purpose
of producing something important, of greatly widening the sphere of
knowledge, it in no way follows that a superfluity of such things
is necessary to him.... He who understands how to put appropriate
questions to Nature, generally knows how to extract the answers by
simple means; and he who wants this capacity will, I fear, obtain no
profitable result, even though all conceivable tools and apparatus may
be ready to his hand."
Nor did Faraday require elaborate apparatus to illustrate his meaning.
Steaming up the Thames one July day in a penny boat, he was struck with
the offensiveness of the water. He tore some white cards into pieces,
wetted them so as to make them sink easily, and dropped them into
the river at each pier they came to. Their sudden disappearance from
sight, though the sun was shining brightly, was proof enough of the
impurity of the stream; and he wrote a letter to the _Times_ describing
his observations, and calling public attention to the dangerous state
of the river.[20] At a meeting of the British Association he wished
to explain the manner in which certain crystallized bodies place
themselves between the poles of an electro-magnet: two or three raw
potatoes furnished the material out of which he cut admirable models of
the crystals. Wishing to show the electrical nature of gun-cotton, he
has been known to lay his watch upon the table, balance on it a slender
piece of wood, and, charging a morsel of the gun-cotton by drawing it
along his coat sleeve, cause the wood to revolve towards the electric
fibres.
"An artist was once maintaining that in natural appearances and in
pictures, up and down, and high and low, were fixed indubitable
realities; but Faraday told him that they were merely conventional
acceptations, based on standards often arbitrary. The disputant could
not be convinced that ideas which he had hitherto never doubted had
such shifting foundations. 'Well,' said Faraday, 'hold a walking-stick
between your chin and your great toe; look along it and say which is
the upper end.' The experiment was tried, and the artist found his idea
of perspective at complete variance with his sense of reality; either
end of the stick might be called 'upper,'--pictorially it was one,
physically it was the other."
Faraday's manner of experimenting may be further illustrated by the
recollections of other friends who have had the opportunity of watching
him at work.
Mr. James Young, who was in the laboratory of University College in
1838, thus writes:--"About that time Professor Graham had got from
Paris Thilorier's apparatus for producing liquid and solid carbonic
acid; hearing of this, Mr. Faraday came to Graham's laboratory, and,
as one might expect, showed great interest in this apparatus, and
asked Graham for the loan of it for a Friday evening lecture at the
Royal Institution, which of course Graham readily granted, and Faraday
asked me to come down to the Institution and give him the benefit of
my experience in charging and working the apparatus; so I spent a long
evening at the Royal Institution laboratory. There was no one present
but Faraday, Anderson, and myself. The principal thing we did was to
charge the apparatus and work with the solid carbonic acid, Mr. Faraday
working with great activity; his motions were wonderfully rapid; and
if he had to cross the laboratory for anything, he did not walk at an
ordinary step, but ran for it, and when he wanted anything he spoke
quickly. Faraday had a theory at that time that all metals would become
magnetic if their temperature were low enough; and he tried that
evening some experiments with cobalt and manganese, which he cooled in
a mixture of carbonic acid and ether, but the results were negative."
Among the deep mines of the Durham coal-field is one called the
Haswell Colliery. One Saturday afternoon, while the men were at work
in it as usual, a terrible explosion occurred: it proceeded from the
fire-damp that collects in the vaulted space that is formed in old
workings, when the supporting pillars of coal are removed and the roof
falls in: the suffocating gases rushed along the narrow passages,
and overwhelmed ninety-five poor fellows with destruction. Of course
there was an inquiry, and the Government sent down to the spot as
their commissioners Professor Faraday and Sir Charles Lyell. The two
gentlemen attended at the coroner's inquest, where they took part
in the examination of the witnesses; they inspected the shattered
safety-lamps; they descended into the mine, spending the best part
of a day in the damaged and therefore dangerous galleries where the
catastrophe had occurred, and they did not leave without showing in a
practical form their sympathy with the sufferers. When down in the pit,
an inspector showed them the way in which the workmen estimated the
rapidity of the ventilation draught, by throwing a pinch of gunpowder
through the flame of a candle, and timing the movement of the little
puff of smoke. Faraday, not admiring the free and easy way in which
they handled their powder, asked where they kept their store of it,
and learnt that it was in a large black bag which had been assigned to
him as the most comfortable seat they could offer. We may imagine the
liveliness with which he sprang to his feet, and expostulated with them
on their culpable carelessness.
My own opportunities of observing Faraday at work were nearly confined
to a series of experiments, which are the better worth describing here
as they have escaped the notice of previous biographers. The Royal
Commission appointed to inquire into our whole system of Lights, Buoys,
and Beacons, perceived a great defect that rendered many of our finest
shore or harbour lights comparatively ineffective. The great central
lamp in a lighthouse is surrounded by a complicated arrangement of
lenses and prisms, with the object of gathering up as many of the rays
as possible and sending them over the surface of the sea towards the
horizon. Now, it is evident that if this apparatus be adjusted so as
to send the beam two or three degrees upwards, the light will be lost
to the shipping and wasted on the clouds; and if two or three degrees
downwards, it will only illuminate the water in the neighbourhood: in
either case the beautiful and expensive apparatus would be worse than
useless. It is evident also that if the eye be placed just above the
wick of the lamp, it will see through any particular piece of glass
that very portion of the landscape which will be illuminated by a ray
starting from the same spot; or the photographic image formed in the
place of the flame by any one of the lenses will tell us the direction
in which that lens will throw the luminous rays. This simple principle
was applied by the Commissioners for testing the adjustment of the
apparatus in the different lights, and it was found that few were
rightly placed, or rather that no method of adjustment was in use
better than the mason's plumbline. The Royal Commissioners therefore
in 1860 drew the attention of all the lighthouse authorities to this
fact, and asked the Elder Brethren of the Trinity House, with Faraday
and other parties, to meet them at the lights recently erected at
the North Foreland and Whitby. I, as the scientific member of the
Commission, had drawn out in detail the course of rays from different
parts of the flame, through different parts of the apparatus, and
I was struck with the readiness with which Faraday, who had never
before considered the matter,[21] took up the idea, and recognized
its importance and its practical application. With his characteristic
ingenuity, too, he devised a little piece of apparatus for the more
exact observation of the matter inside the lighthouse. He took to Mr.
Ladd, the optical instrument maker, a drawing, very neatly executed,
with written directions, and a cork cut into proper shape with two
lucifer matches stuck through it, to serve as a further explanation of
his meaning: and from this the "focimeter," as he called it, was made.
The position of the glass panels at Whitby was corrected by means of
this little instrument, and there were many journeys down to Chance's
glassworks near Birmingham, where, declining the hospitality of the
proprietor in order to be absolutely independent, he put up at a small
hotel while he made his experiments, and jotted down his observations
on the cards he habitually carried in his pocket. At length we were
invited down to see the result. Faraday explained carefully all that
had been done, and at the risk of sea-sickness (no trifling matter in
his case) accompanied us out to sea to observe the effect from various
directions and at various distances. The experience acquired at Whitby
was applied elsewhere, and in May 1861 the Trinity House appointed a
Visiting Committee, "to examine all dioptric light establishments, with
the view of remedying any inaccuracies of arrangement that may be found
to exist." Faraday had instructed and practised Captain Nisbet and some
others of the Elder Brethren in the use of the focimeter, and now wrote
a careful letter of suggestions on the question of adjustment between
the lamp and the lenses and prisms; so thoughtfully did he work for the
benefit of those who "go down to the sea in ships, that do business in
great waters."
As to the mental process that devised, directed, and interpreted
his experiments, it must be borne in mind that Faraday was no
mathematician; his power of appreciating an _à priori_ reason often
appeared comparatively weak. "It has been stated on good authority
that Faraday boasted on a certain occasion of having only once in the
course of his life performed a mathematical calculation: that once
was when he turned the handle of Babbage's calculating machine."[22]
Though there was more pleasantry than truth in this professed innocence
of numbers, probably no one acquainted with his electrical researches
will doubt that, had he possessed more mathematical ability, he would
have been saved much trouble, and would sometimes have expressed his
conclusions with greater ease and precision. Yet, as Sir William
Thomson has remarked with reference to certain magnetic phenomena,
"Faraday, without mathematics, divined the result of the mathematical
investigation; and, what has proved of infinite value to the
mathematicians themselves, he has given them an articulate language
in which to express their results. Indeed, the whole language of the
magnetic field and 'lines of force' is Faraday's. It must be said for
the mathematicians that they greedily accepted it, and have ever since
been most zealous in using it to the best advantage."
The peculiarity of his mind was indeed well known to himself. In a
letter to Dr. Becker he says: "I was never able to make a fact my own
without seeing it; and the descriptions of the best works altogether
failed to convey to my mind such a knowledge of things as to allow
myself to form a judgment upon them. It was so with _new_ things. If
Grove, or Wheatstone, or Gassiot, or any other told me a new fact, and
wanted my opinion either of its value, or the cause, or the evidence it
could give on any subject, I never could say anything until I had seen
the fact. For the same reason I never could work, as some Professors do
most extensively, by students or pupils. All the work had to be my own."
Thus we are told what took place "when Dr. Tyndall brought Mr. Faraday
into the laboratory to look at his new discovery of calorescence. As
Faraday saw for the first time a piece of cold, black platinum raised
to a dazzling brightness when held in the focus of dark rays, a point
undistinguishable from the air around, he looked on attentively,
putting on his spectacles to observe more carefully, then ascertained
the conditions of the experiment, and repeated it for himself; and now
quite satisfied, he turned with emotion to Dr. Tyndall, and almost
hugged him with pleasure."[23]
The following story by Mr. Robert Mallet also serves as an
illustration:--"It must be now eighteen years ago when I paid him a
visit and brought some slips of flexible and _tough_ Muntz's yellow
metal, to show him the instantaneous change to complete brittleness
with rigidity produced by dipping into pernitrate of mercury solution.
He got the solution, and I _showed_ him the facts; he obviously did
not doubt what he saw _me_ do before and close to him: but a sort of
experimental instinct seemed to require he should try it himself. So
he took one of the slips, bent it forwards and backwards, dipped it,
and broke it up into short bits between his own fingers. He had not
before spoken. _Then_ he said, 'Yes, it _is_ pliable, and it _does_
become instantly brittle.' And after a few moments' pause he added,
'Well, now have you any more facts of the sort?' and seemed a little
disappointed when I said, 'No; none that are new.' It has often since
occurred to me how his mind needed absolute satisfaction that he had
grasped a _fact_, and then instantly rushed to colligate it with
another if possible."
But as the Professor watched these new facts, new thoughts would shape
themselves in his mind, and this would lead to fresh experiments in
order to test their truth. The answers so obtained would lead to
further questions. Thus his work often consisted in the defeat of one
hypothesis after another, till the true conditions of the phenomena
came forth and claimed the assent of the experimenter and ultimately of
the scientific world.
A. de la Rive has some acute observations on this subject. He explains
how Faraday did not place himself before his apparatus, setting it
to work, without a preconceived idea. Neither did he take up known
phenomena, as some scientific men do, and determine their numerical
data, or study with great precision the laws which regulate them.
"A third method, very different from the preceding, is that which,
quitting the beaten track, leads, as if by inspiration, to those great
discoveries which open new horizons to science. This method, in order
to be fertile, requires one condition--a condition, it is true, which
is but rarely met with--namely, genius. Now, this condition existed in
Faraday. Endowed, as he himself perceived, with much imagination, he
dared to advance where many others would have recoiled: his sagacity,
joined to an exquisite scientific tact, by furnishing him with a
presentiment of the possible, prevented him from wandering into the
fantastic; while, always wishing only for facts, and accepting theories
only with difficulty, he was nevertheless more or less directed by
preconceived ideas, which, whether true or false, led him into new
roads, where most frequently he found what he sought, and sometimes
also what he did not seek, but where he constantly met with some
important discovery.
"Such a method, if indeed it can be called one, although barren and
even dangerous with mediocre minds, produced great things in Faraday's
hands; thanks, as we have said, to his genius, but thanks also to that
love of truth which characterized him, and which preserved him from the
temptation so often experienced by every discoverer, of seeing what he
wishes to see, and not seeing what he dreads."
This love of truth deserves a moment's pause. It was one of the most
beautiful and most essential of his characteristics; it taught him
to be extremely cautious in receiving the statements of others or in
drawing his own conclusions,[24] and it led him, if his scepticism was
overcome, to adopt at once the new view, and to maintain it, if need
be, against the world.
"The thing I am proudest of, Pearsall, is that I have never been found
to be wrong," he could say in the early part of his scientific history
without fear of contradiction. After his death A. de la Rive wrote, "I
do not think that Faraday has once been caught in a mistake; so precise
and conscientious was his mode of experimenting and observing."
This is not absolutely true; but the extreme rarity of his mistakes,
notwithstanding the immense amount of his published researches, is one
of those marvels which can be appreciated only by those who are in the
habit of describing what they have seen in the mist land that lies
beyond the boundaries of previous knowledge.
Into this unknown region his mental vision was ever stretched. "I
well remember one day," writes Mr. Barrett, a former assistant at the
Royal Institution, "when Mr. Faraday was by my side, I happened to
be steadying, by means of a magnet, the motion of a magnetic needle
under a glass shade. Mr. Faraday suddenly looked most impressively and
earnestly as he said, 'How wonderful and mysterious is that power you
have there! the more I think over it the less I seem to know:'--and yet
he who said this knew more of it than any living man."
It is easy to imagine with what wonder he would stand before the apples
or leaves or pieces of meat that swung round into a transverse position
between the poles of his gigantic magnet, or the sand that danced
and eddied into regular figures on plates of glass touched by the
fiddle-bow, or gold so finely divided that it appeared purple and when
diffused in water took a twelvemonth to settle. It is easy, too, to
imagine how he would long to gain a clear idea of what was taking place
behind the phenomena. But it is far from easy to grasp the conceptions
of his brain: language is a clumsy vehicle for such thoughts. He
strove to get rid of such figurative terms as "currents" and "poles;"
in discussing the mode of propagation of light and radiant heat he
endeavoured "to dismiss the ether, but not the vibrations;" and in
conceiving of atoms, he says: "As to the little solid particles ... I
cannot form any idea of them apart from the forces, so I neither admit
nor deny them. They do not afford me the least help in my endeavour to
form an idea of a particle of matter. On the contrary, they greatly
embarrass me." Yet he could not himself escape from the tyranny of
words or the deceitfulness of metaphors, and it is hard for his readers
to comprehend what was his precise idea of those centres of forces that
occupy no space, or of those lines of force which he beheld with his
mental eye, curving alike round his magnetic needle, and that mightiest
of all magnets--the earth.
As he was jealous of his own fame, and had learnt by experience that
discoveries could be stolen, he talked little about them till they
were ready for the public; indeed, he has been known to twit a brother
electrician for telling his discoveries before printing them, adding
with a knowing laugh, "I never do that." He was obliged, however,
to explain his results to Professor Whewell, or some other learned
friend, if he wished to christen some new idea with a Greek name.
One of Whewell's letters on such an occasion, dated Trinity College,
Cambridge, October 14, 1837, begins thus:--
"MY DEAR SIR,
"I am always glad to hear of the progress of your researches, and
never the less so because they require the fabrication of a new word
or two. Such a coinage has always taken place at the great epochs of
discovery; like the medals that are struck at the beginning of a new
reign, or rather like the change of currency produced by the accession
of a new Sovereign; for their value and influence consists in their
coming into common circulation."
* * * * *
During the whole time of an investigation Faraday had kept ample notes,
and when all was completed he had little to do but to copy these notes,
condensing or re-arranging some parts, and omitting what was useless.
The paper then usually consisted of a series of numbered paragraphs,
containing first a statement of the subject of inquiry, then a series
of experiments giving negative results, and afterwards the positive
discoveries. In this form it was sent to the Royal Society or some
other learned body. Yet this often involved considerable labour, as the
following words written to Miss Moore in 1850 from a summer retreat in
Upper Norwood will show:--"I write and write and write, until nearly
three papers for the Royal Society are nearly completed, and I hope
that two of them will be good if they do justify my hopes, for I have
to criticise them again and again before I let them loose. You shall
hear of them at some of the next Friday evenings."
This criticism did not cease with their publication, for he endeavoured
always to improve on his previous work. Thus, in 1832 he bound his
papers together in one volume, and the introduction on the fly-leaf
shows the object with which it was done:--
"Papers of mine, published in octavo, in the _Quarterly Journal of
Science_, and elsewhere, since the time that Sir H. Davy encouraged me
to write the analysis of caustic lime.
"Some, I think (at this date), are good, others moderate, and some
bad. But I have put _all_ into the volume, because of the utility they
have been of to me--and none more than the bad--in pointing out to me
in future, or rather after times, the faults it became me to watch and
to avoid.
"As I never looked over one of my papers a year after it was written,
without believing, both in philosophy and manner, it could have been
much better done, I still hope the collection may be of great use to
me.
"M. FARADAY.
"_August 18, 1832_."
* * * * *
This section may be summed up in the words of Dumas when he gave the
first "Faraday Lecture" of the Chemical Society:--"Faraday is the type
of the most fortunate and the most accomplished of the learned men of
our age. His hand in the execution of his conceptions kept pace with
his mind in designing them; he never wanted boldness when he undertook
an experiment, never lacked resources to ensure success, and was full
of discretion in interpreting results. His hardihood, which never
halted when once he had undertaken a task, and his wariness, which felt
its way carefully in adopting a received conclusion, will ever serve as
models for the experimentalist."
FOOTNOTES:
[18] "Mittheilungen aus dem Reisetagebuche eines deutschen
Naturforschers," p. 275.
[19] Since the publication of the first edition I have been struck
with how precisely his practice corresponded with his precept in
the introduction to his book on "Chemical Manipulation:"--"When an
experiment has been devised, its general nature and principles arranged
in the mind, and the causes to be brought into action, with the effect
to be expected, properly considered, then it has to be performed. The
ultimate objects of an experiment, and also the particular contrivance
or mode by which the results are to be produced, being mental, there
remains the mere performance of it, which may properly enough be
expressed by the term _manipulation_.
"Notwithstanding this subordinate character of manipulation, it is
yet of high importance in an experimental science, and particularly
in chemistry. The person who could devise only, without knowing how
to perform, would not be able to extend his knowledge far, or make it
useful; and where every doubt or question that arises in the mind is
best answered by the result of an experiment, whatever enables the
philosopher to perform the experiment in the simplest, quickest, and
most direct manner, cannot but be esteemed by him as of the utmost
value."
[20] _Punch's_ cartoon next week represented Professor Faraday holding
his nose, and presenting his card to Father Thames, who rises out of
the unsavoury ooze.
[21] Since writing the above I have come across a letter written by
Faraday in answer to one by Captain Welier as far back as 13th Sept.
1839, in which he pointed out the mal-adjustment of the dioptric
apparatus at Orfordness. In July of the following year he made lengthy
suggestions to the Trinity House, in which he proposed using a flat
white circle or square, half an inch across, on a piece of black paper
or card, as a "focal object." This was to be looked at from outside, in
order to test the regularity of the glass apparatus. He also suggested
observations on the divergence by looking at this white circle at a
distance of twenty feet at most. Another plan he proposed was that of
lighting the lamp and putting up a white screen outside. These methods
of examining he carried out very shortly afterwards at Blackwall, on
French and English refractors, but it seems never to have occurred to
him to place his eye in the focus, or in any other manner to observe
the course of the rays from inside the apparatus.
[22] Dr. Scoffern, _Belgravia_, October 1867.
[23] Mr. Barrett, _Nature_, Sept. 19, 1872.
[24] A good instance of his caution in drawing conclusions is contained
in one of his letters to me:--
"ROYAL INSTITUTION OF GREAT BRITAIN,
"_2 July, 1859_.
"MY DEAR GLADSTONE,
"Although I have frequently observed lights from the sea, the only
thing I have learnt in relation to their _relative brilliancy_ is that
the average of a very great number of observations would be required
for the attainment of a moderate approximation to truth. One has to
be some miles off at sea, or else the observation is not made in the
chief ray, and then one does not know the state of the atmosphere
about a given lighthouse. Strong lights like that of Cape Grisnez have
been invisible when they should have been strong; feeble lights by
comparison have risen up in force when one might have expected them to
be relatively weak; and after inquiry has not shown a state of the air
at the lighthouse explaining such differences. It is probable that the
cause of difference often exists at sea.
"Besides these difficulties there is that other great one of not
seeing the two lights to be compared in the field of view at the same
time and same distance. If the eye has to turn 90° from one to the
other, I have no confidence in the comparison; and if both be in the
field of sight at once, still unexpected and unexplained causes of
difference occur. The two lights at the South Foreland are beautifully
situated for comparison, and yet sometimes the upper did not equal the
lower when it ought to have surpassed it. This I referred at the time
to an upper stratum of haze; but on shore they knew nothing of the
kind, nor had any such or other reason to expect particular effects.
"Ever truly yours,
"M. FARADAY."
As an instance of his unwillingness to commit himself to an opinion
unless he was sure about it, may be cited a letter he wrote to Sir
G. B. Airy, the Astronomer Royal, who asked for his advice in regard
to the material of which the national standard of length should be
made:--"I do not see any reason why a pure metal should be particularly
free from internal change of its particles, and on the whole should
rather incline to the hard alloy than to soft copper, and yet I hardly
know why. I suppose the labour would be too great to lay down the
standard on different metals and substances; and yet the comparison of
them might be very important hereafter, for twenty years seem to _do_
or _tell_ a great deal in relation to standard measures." Bronze was
finally chosen.