Part 10

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.