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  • ID: I11035
  • Name: John William STRUTT
  • Given Name: John William
  • Surname: Strutt
  • Suffix: FRS, 3rd Lord Rayleigh
  • Title: FRS, 3rd Lord Rayleigh
  • Sex: M
  • Birth: 12 NOV 1842 in Maldon (Essex) England
  • Death: 30 JUN 1919 in Witham (Essex) England
  • Note:
    Nobel prize for physics 1904
    Used "fresh country air" in his experiments -see Nobel lecture Dec 12 1904.

    John William Strutt, third Baron Rayleigh, was born on November 12, 1842 at Langford Grove, Maldon, Essex, as the son of John James Strutt, second Baron, and his wife Clara Elizabeth La Touche, eldest daughter of Captain Richard Vicars, R.E. He was one of the very few members of higher nobility who won fame as an outstanding scientist.

    Throughout his infancy and youth he was of frail physique; his education was repeatedly interrupted by ill-health, and his prospects of attaining maturity appeared precarious. After a short spell at Eton at the age of 10, mainly spent in the school sanatorium, three years in a private school at Wimbledon, and another short stay at Harrow, he finally spent four years with the Rev. George Townsend Warner (1857) who took pupils at Torquay.

    In 1861 he entered Trinity College, Cambridge, where he commenced reading mathematics, not at first equal in attainments to the best of his contemporaries, but his exceptional abilities soon enabled him to overtake his competitors. He graduated in the Mathematical Tripos in 1865 as Senior Wrangler and Smith's Prizeman. In 1866 he obtained a fellowship at Trinity which he held until 1871, the year of his marriage.

    A severe attack of rheumatic fever in 1872 made him spend the winter in Egypt and Greece. Shortly after his return his father died (1873) and he succeeded to the barony, taking up residence in the family seat, Terling Place, at Witham, Essex. He now found himself compelled to devote part of his time to the management of his estates (7000 acres). The combination of general scientific knowledge and acumen with acquired knowledge of agriculture made his practice in estate management in many respects in advance of his time. Nevertheless, in 1876 he left the entire management of the land to his younger brother.

    From then on, he could devote his full time to science again. In 1879 he was appointed to follow James Clerk Maxwell as Professor of Experimental Physics and Head of the Cavendish Laboratory at Cambridge. In 1884 he left Cambridge to continue his experimental work at his country seat at Terling, Essex, and from 1887 to 1905 he was Professor of Natural Philosophy in the Royal Institution of Great Britain, being successor of Tyndall.

    He served for six years as President of a Government Committee on Explosives, and from 1896 to 1919 he was Scientific Advisor to Trinity House. He was Lord Lieutenant of Essex from 1892 to 1901.

    Lord Rayleigh's first researches were mainly mathematical, concerning optics and vibrating systems, but his later work ranged over almost the whole field of physics, covering sound, wave theory, colour vision, electrodynamics, electromagnetism, light scattering, flow of liquids, hydrodynamics, density of gases, viscosity, capillarity, elasticity, and photography. His patient and delicate experiments led to the establishment of the standards of resistance, current, and electromotive force; and his later work was concentrated on electric and magnetic problems. Lord Rayleigh was an excellent instructor and, under his active supervision, a system of practical instruction in experimental physics was devised at Cambridge, developing from a class of five or six students to an advanced school of some seventy experimental physicists. His Theory of Sound was published in two volumes during 1877-1878, and his other extensive studies are reported in his Scientific Papers - six volumes issued during 1889-1920. He has also contributed to the Encyclopaedia Britannica.

    He had a fine sense of literary style; every paper he wrote, even on the most abstruse subject, is a model of clearness and simplicity of diction. The 446 papers reprinted in his collected works clearly show his capacity for understanding everything just a little more deeply than anyone else. Although a member of the House of Lords, he intervened in debate only on rare occasions, never allowing politics to interfere with science. His recreations were travel, tennis, photography and music.

    Lord Rayleigh, a former Chancellor of Cambridge University, was a Justice of the Peace and the recipient of honorary science and law degrees. He was a Fellow of the Royal Society (1873) and served as Secretary from 1885 to 1896, and as President from 1905 to 1908. He was an original recipient of the Order of Merit (1902), and in 1905 he was made a Privy Councillor. He was awarded the Copley, Royal, and Rumford Medals of the Royal Society, and the Nobel Prize for 1904.

    In 1871 he married Evelyn, sister of the future prime minister, the Earl of Balfour, and daughter of James Maitland Balfour and his wife Blanche, the daughter of the second Marquis of Salisbury. They had three sons, the eldest of whom was to become Professor of Physics at Imperial College of Science and Technology, London.

    Lord Rayleigh died on June 30, 1919, at Witham, Essex.
    [From Nobel Lectures, Physics 1901-1921.]

    On receiving the Order of Merit in 1902 he said:-
    "... the only merit of which I personally am conscious was that of having pleased myself by my studies, and any results that may be due to my researches were owing to the fact that it has been a pleasure for me to become a physicist. "

    Rayleigh had received correspondence from Professor Ramsay, a chemist at University College London, who had himself begun to examine the characteristics of the atmospheric nitrogen using magnesium as a reagent following Rayleigh's earlier publication of his initial findings. This was regarded by many at the time as a breach of scientific etiquette. Correspondence of the day indicates that Ramsay kept Rayleigh informed of his progress in the isolation of the gas. The efforts by Ramsay had put Rayleigh under some pressure to complete his experiments more rapidly than he would have preferred.

    A joint paper entitled, `Argon, a New Constituent of the Atmosphere', was presented at a meeting of the Royal Society on 31st January 1895. The findings were not universally accepted by the chemical fraternity at the time. Certain criticisms pointed to the fact that so heavy an element could not possibly be a gas. Rayleigh's reply was characteristic:

    `The result is no doubt very awkward.... and all we can do is apologize for ourselves and the gas'.

    For this work Rayleigh was to be awarded the Nobel Prize for Physics in 1904. In that same year, Ramsay was awarded the Nobel Prize in Chemistry for his work on the isolation of argon and helium and, with Travers, the other noble gases neon, krypton and xenon.

    {Crookes:William Crookes (1832-1919) - English chemist and physicist; His investigations of the photographic process in the 1850s motivated his work in the new science of spectroscopy. Using its techniques, Crooks discovered (1861) the element thallium, which won him election to the Royal Society. His efforts in determining the weight of thalium in an evacuated chamber led to his research in vacuum physics.
    Crookes invented the radiometer in 1875 and, beginning in 1878, investigated electrical discharges through highly evaculated "Crookes tubes." These studies laid the foundation for J. J. Thomson's research in the late 1890's concerning discharge-tube phenomena. At the age of 68, Crookes began investigating the phenomenon of radioactivity, which had been discovered in 1896, and invented a device that detected alpha particles emitted from radioactive material. Crookes maintained an interest in agriculture and warned in 1898 that the world's population would face starvation unless new fertilizer sources were discovered. He was also interested in psychic phenomena. He was knighted in 1897. ]
    Sir William Crookes' interest in this field was shared by other prominent physicists like Lord Rayleigh (who was President of the Society for Psychical Research) and Sir Oliver Lodge. Here Rayleigh takes the chair at a public lecture by Lodge:
    Royal Institution: Friday, February 21, 1908

    The Ether of Space

    THIRTY years ago Clerk Maxwell gave in this place a remarkable address on "Action at a Distance." It is reported in your Journal, Vol. VII., and to it I would direct attention. Most natural philosophers hold, and have held, that action at a distance across empty space is impossible-in other words, that matter cannot act where it is not, but only where it is.

    The question "where is it?" is a further question that may demand attention and require more than a superficial answer. For it can be argued on the hydrodynamic or vortex theory of matter, as well as on the electrical theory, that every atom of matter has a universal though nearly infinitesimal prevalence, and extends everywhere; since there is no definite sharp boundary or limiting periphery to the region disturbed by its existence.

    The lines of force of an isolated electric charge extend throughout illimitable space. And though a charge of opposite sign will curve and concentrate them, yet it is possible to deal with both charges, by the method of superposition, as if they each existed separately without the other. In that case, therefore, however far they reach, such nuclei clearly exert no "action at a distance" in the technical sense.

    Some philosophers have reason to suppose that mind can act directly on mind without intervening mechanism, and sometimes that has been spoken of as genuine action at a distance; but, in the first place, no proper conception or physical model can be made of such a process, nor is it clear that space and distance have any particular meaning in the region of psychology. The links between mind and mind may be something quite other than physical proximity, and in denying action at a distance across empty space I am not denying telepathy or other activities of a non-physical kind-for although brain disturbance is certainly physical and is an essential concomitant of mental action, whether of the sending or receiving variety, yet we know from the case of heat that a material movement can be excited in one place at the expense of corresponding movement in another, without any similar kind of transmission or material connection between the two places: the thing that travels across vacuum is not heat.

    In all cases where physical motion is involved, however, I would have a medium sought for; it may not be matter, but it must be something; there must be a connecting link of some kind, or the transference cannot occur. There can be no attraction across really empty space. And even when a material link exists, so that the connexion is obvious, the explanation is not complete-for when the mechanism of attraction is understood, it will be found that a body really only moves because it is pushed by something from behind.

    The essential force in nature is the vis a tergo. So when we have found the "traces," or discovered the connecting thread, we still run up against the word "cohesion," and ought to be exercised in our minds as to its ultimate meaning. Why the whole of a rod should follow, when one end is pulled, is a matter requiring explanation; and the only explanation that can be given involves, in some form or other, a continuous medium connecting the discrete and separated particles or atoms of matter.

    When a steel spring is bent or distorted, what is it that is really strained? Not the atoms-the atoms are only displaced; it is the connecting links that are strained-the connecting medium-the ether. Distortion of a spring is really distortion of the ether. All stress exists in the ether.

    Matter can only be moved. Contact does not exist between the atoms of matter as we know them; it is doubtful if a piece of matter ever touches another piece, any more than a comet touches the sun when it appears to rebound from it; but the atoms are connected, as the comet and the sun are connected by a continuous plenum without break or discontinuity of any kind.

    Matter acts on matter only through the ether. But whether matter is a thing utterly distinct and separate from the ether, or whether it is a specifically modified portion of it-modified in such a way as to be susceptible of locomotion, and yet continuous with all the rest of the ether, which can be said to extend everywhere-far beyond the bounds of the modified and tangible portion-are questions demanding, and I may say in process of receiving, answers. Every such answer involves some view of the universal and possibly infinite uniform omnipresent connecting medium, the Ether of space.

    It has been said, somewhat sarcastically, that the ether was made in England. The statement is only an exaggeration of the truth. I might even urge that it has been largely constructed in the Royal Institution; for, I will remind you now of the chief lines of evidence on which its existence is believed in, and our knowledge of it is based. First of all, Newton recognised the need of a medium for explaining gravitation. In his "Optical Queries" he shows that if the pressure of this medium is less in the neighbourhood of dense bodies than at great distances from them, dense bodies will be driven towards each other; and that if the diminution of pressure is inversely as the distance from the dense body, the law will be that of gravitation.

    All that is required, therefore, to explain gravity is a diminution of pressure, or increase of tension, caused by the formation of a matter unit-that is to say of an electron or corpuscle; and although we do not yet know what an electron is-whether it be a strain centre, or what kind of singularity in the ether it may be-there is no difficulty in supposing that a slight, almost infinitesimal, strain or attempted rarefaction should be produced in the ether whenever an electron came into being-to be relaxed again only on its resolution and destruction. Strictly speaking it is not a real strain, but only a "stress"; since there can be no actual yield, but only a pull or tension, extending in all directions towards infinity.

    The tension required per unit of matter is almost ludicrously small, and yet in the aggregate, near such a body as a planet, it becomes enormous. The force with which the moon is held in its orbit would be great enough to tear asunder a steel rod four hundred miles thick, with a tenacity of 30 tons per square inch; so that if the moon and earth were connected by steel instead of by gravity, a forest of pillars would be necessary to whirl the system once a month round their common centre of gravity.

    Such a force necessarily implies enormous tension or pressure in the medium. Maxwell calculates that the gravitational stress near the earth, which we must suppose to exist in the invisible medium, is 3000 times greater than what the strongest steel could stand; and near the sun it should be 2500 times as great as that.

    The question has arisen in my mind, whether, if the whole sensible universe-estimated by Lord Kelvin as equivalent to about a thousand million suns-were all concentrated in one body of specifiable density, the stress would not be so great as to produce a tendency towards etherial disruption; which would result in a disintegrating explosion, and a scattering of the particles once more as an enormous nebula and other fragments into the depths of space. For the tension would be a maximum in the interior of such a mass; and, if it rose to the value 10^33 dynes per square centimetre, something would have to happen. I do not suppose that this can be the reason, but one would think there must be some reason, for the scattered condition of gravitative matter.

    Too little is known, however, about the mechanism of gravitation to enable us to adduce it as the strongest argument in support of the existence of an ether. The oldest valid and conclusive requisition of an etherial medium depends on the wave theory of light, one of the founders of which was your Professor of Natural Philosophy at the beginning of last century, Dr. Thomas Young. No ordinary matter is capable of transmitting the undulations or tremors that we call light. The speed at which they go, the kind of undulation, and the facility with which they go through vacuum, forbid this.

    So clearly and universally has it been perceived that waves must be waves of something- something distinct from ordinary matter-that Lord Salisbury, in his presidential address to the British Association at Oxford, criticised the ether as little more than a nominative case to the verb to undulate.

    It is truly that, though it is also truly more than that; but to illustrate that luminiferous aspect of it, I will quote a paragraph from that lecture of Clerk Maxwell's to which I have already referred:

    "The vast interplanetary and interstellar regions will no longer be regarded as waste places in the universe, which the Creator has not seen fit to fill with the symbols of the manifold order of His kingdom. We shall find them to be already full of this wonderful medium; so full, that no human power can remove it from the smallest portion of Space, or produce the slightest flaw in its infinite continuity. It extends unbroken from star to star; and when a molecule of hydrogen vibrates in the dog-star, the medium receives the impulses of these vibrations, and after carrying them in its immense bosom for several years, delivers them, in due course, regular order, and full tale, into the spectroscope of Mr. Huggins, at Tulse Hill."

    (It is pleasant to remember that those veteran investigators Sir William and Lady Huggins are still at work.)

    This will suffice to emphasise the fact that the eye is truly an etherial sense-organ-the only one which we possess, the only mode by which the ether is enabled to appeal to us, and that the detection of tremors in this medium-the perception of the direction in which they go, and some inference as to the quality of the object which has emitted them-cover all that we mean by "sight" and "seeing."

    I pass then to another function, the electric and magnetic phenomena displayed by the ether; and on this I will only permit myself a very short quotation from the writings of Faraday, whose whole life may be said to have been directed towards a better understanding of these ethereous phenomena.

    Indeed, the statue in your entrance hall may be considered as the statue of the discoverer of the electric and magnetic properties of the Ether of space. Faraday conjectured that the same medium which is concerned in the propagation of light might also be the agent in electromagnetic phenomena. He says:

    "For my own part, considering the relation of a vacuum to the magnetic force, and the general character of magnetic phenomena external to the magnet, I am much more inclined to the notion that in the transmission of the force there is such an action, external to the magnet, than that the effects are merely attraction and repulsion at a distance. Such an action may be a function of the aether; for it is not unlikely that, if there be an aether, it should have other uses than simply the conveyance of radiation."

    This conjecture has been amply strengthened by subsequent investigations. One more function is now being discovered; the ether is being found to constitute matter-an immensely interesting topic, on which there are many active workers at the present time. I will make a brief quotation from your present Professor of Natural Philosophy (J. J. Thomson), where he summarises the conclusion which we all see looming before us, though it has not yet been completely attained, and would not by all be similarly expressed:

    "The whole mass of any body is just the mass of ether surrounding the body which is carried along by the Faraday tubes associated with the atoms of the body. In fact, all mass is mass of the ether; all momentum, momentum of the ether; and all kinetic energy, kinetic energy of the ether. This view, it should be said, requires the density of the ether to be immensely greater than that of any known substance."

    Yes, far denser-so dense that matter by comparison is like gossamer, or a filmy imperceptible mist, or a milky way. Not unreal or unimportant-a cobweb is not unreal, nor to certain creatures is it unimportant, but it cannot be said to be massive or dense; and matter, even platinum, is not dense when compared with the ether. Not till last year, however, did I realise what the density of the ether must really be, compared with that modification of it which appeals to our senses as matter, and which for that reason engrosses our attention. If I have time I will return to that before I have finished. Is there any other function possessed by the ether, which, though not yet discovered, may lie within the bounds of possibility for future discovery?

    I believe there is, but it is too speculative to refer to, beyond saying that it has been urged as probable by the authors of "The Unseen Universe," and has been thus tentatively referred to by Clerk Maxwell:

    "Whether this vast homogeneous expanse of isotropic matter is fitted not only to be a medium of physical interaction between distant bodies, and to fulfil other physical functions of which, perhaps, we have as yet no conception, but also to constitute the material organism of beings exercising functions of life and mind as high or higher than ours are at present-is a question far transcending the limits of physical speculation."

    And there for the present I leave that aspect of the subject. I shall now attempt to illustrate some relations between ether and matter. The question is often asked, is ether material? This is largely a question of words and convenience. Undoubtedly, the ether belongs to the material or physical universe, but it is not ordinary matter. I should prefer to say it is not "matter" at all. It may be the substance or substratum or material of which matter is composed, but it would be confusing and inconvenient not to be able to discriminate between matter on the one hand, and ether on the other hand, if you tie a knot on a bit of string, the knot is composed of string; but the string is not composed of knots. If you have a smoke or vortex-ring in the air, the vortex-ring is made of air, but the atmosphere is not a vortex-ring; and it would be only confusing to say that it was.

    The essential distinction between matter and ether is that matter moves, in the sense that it has the property of locomotion and can effect impact and bombardment; while ether is strained, and has the property of exerting stress and recoil. All potential energy exists in the ether. It may vibrate, and it may rotate, but as regards locomotion it is stationary-the most stationary body we know- absolutely stationary, so to speak; our standard of rest.

    All that we ourselves can effect, in the material universe, is to alter the motion and configuration of masses of matter, we can move matter, by our muscles, and that is all we can do directly: everything else is indirect. But now comes the question, how is it possible for matter to be composed of ether? How is it possible for a solid to be made out of fluid? A solid possesses the properties of rigidity, impenetrability, elasticity, and such like; how can these be imitated by a perfect fluid such as the ether must be? The answer is, they can be imitated by a fluid in motion; a statement which we make with confidence as the result of a great part of Lord Kelvin's work.

    It may be illustrated by a few experiments.

    A wheel of spokes, transparent or permeable when stationary, becomes opaque when revolving, so that a ball thrown against it does not go through, but rebounds. The motion only affects permeability to matter; transparency to light is unaffected.

    A silk cord hanging from a pulley becomes rigid and viscous when put, into rapid motion; and pulses or waves which may be generated on the cord travel along it with a speed equal to its own velocity, whatever that velocity may be, so that they appear to stand still.

    This is a case of kinetic rigidity; and the fact that the wave-transmission velocity is equal to the rotatory speed of the material, is typical and important, for in all cases of kinetic elasticity these two velocities are of the same order of magnitude.

    A flexible chain, set spinning, can stand up on end while the motion continues.

    A jet of water at sufficient speed can be struck with a hammer, and resists being cut with a sword.

    A spinning disk of paper becomes elastic like flexible metal, and can act like a circular saw.

    Sir William White tells me that in naval construction steel plates are cut by a rapidly revolving disk of soft iron.

    A vortex-ring, ejected from an elliptical orifice, oscillates about the stable circular form, as an India rubber ring would do; thus furnishing a beautiful example of kinetic elasticity, and showing us clearly a fluid displaying some of the properties of a solid.

    A still further example is Lord Kelvin's model of a spring balance, made of nothing but rigid bodies in spinning motion.

    If the ether can be set spinning, therefore, we may have some hope of making it imitate the properties of matter, or even of constructing matter by its aid. But how are we to spin the ether?

    Matter alone seems to have no grip of it. I have spun steel disks, a yard in diameter, 4000 times a minute, have sent light round and round between them, and tested carefully for the slightest effect on the ether. Not the slightest effect was perceptible. We cannot spin ether mechanically.

    But we can vibrate it electrically; and every source of radiation does that. An electrified body, in sufficiently rapid vibration, is the only source of ether-waves that we know; and if an electric charge is suddenly stopped, it generates the pulses known as X-rays, as the result of the collision. Not speed, but sudden change of speed, is the necessary condition for generating waves in the ether by electricity.

    We can also infer some kind of rotary motion in the ether; though we have no such obvious means of detecting the spin as is furnished by vision for detecting some kinds of vibration. It is supposed to exist whenever we put a charge into the neighbourhood of a magnetic pole. Round the line joining the two, the ether is spinning like a top. I do not say it is spinning fast: that is a question of its density; it is in fact spinning with excessive slowness, but it is spinning with a definite moment of momentum. J. J. Thomson's theory makes its moment of momentum exactly equal to e*m, the product of charge and pole; the charge being measured electrostatically and the pole magnetically.

    How can this be shown experimentally? Suppose we had a spinning top enclosed in a case, so that the spin was unrecognisable by ordinary means-it could he detected by its gyrostatic behaviour to force. If allowed to "precess" it will respond by moving perpendicularly to a deflecting force. So it is with the charge and the magnetic pole. Try to move the charge suddenly, and it immediately sets off at right angles.

    A moving charge is a current, and the pole and the current try to revolve round one another-a true gyrostatic action due to the otherwise unrecognizable etherial spin. The fact of such magnetic rotation was discovered by Faraday. I know that it is usually worked out in another way, in terms of lines of force and the rest of the circuit; but I am thinking of a current as a stream of projected charges; and no one way of regarding such a matter is likely to exhaust the truth, or to exclude other modes which are equally valid. Anyhow, in whatever way it is regarded, it is an example of the three rectangular vectors.

    The three vectors at right angles to each other, which may be labelled Current, Magnetism, and Motion respectively, or more generally E, H, and V, represent the quite fundamental relation between ether and matter, and constitute the link between Electricity, Magnetism, and Mechanics. Where any two of these are present, the third is a necessary consequence. This principle is the basis of all dynamos, of electric motors, of light, of telegraphy, and of most other things.

    Indeed, it is a question whether it does not underlie everything that we know in the whole of the physical sciences; and whether it is not the basis of our conception of the three dimensions of space.

    Lastly, we have the fundamental property of matter called inertia, which, if I had time, I would show could be explained electromagnetically provided the etherial density is granted as of the order 10^12 grammes per cubic centimetre. The elasticity of the ether would then have to be of the order 10^33 c.g.s.; and if this is due to intrinsic turbulence, the speed of the whirling or rotational elasticity must be of the same order as the velocity of light. This follows hydrodynamically; in the same sort of way as the speed at which a pulse travels on a flexible running endless cord, whose tension is entirely due to the centrifugal force of the motion, is precisely equal to the velocity of the cord itself.

    And so, on our present view, the intrinsic energy of constitution of the ether is incredibly and portentously great, every cubic millimetre of space possessing what, if it were matter, would be a mass of a thousand tons, and an energy equivalent to the output of a million-horse-power-station for 40 million years.

    The universe we are living in is an extraordinary one; and our investigation of it has only just begun. We know that matter has a psychical significance, since it can constitute brain, which links together the physical and the psychical worlds. If anyone thinks that the ether, with all its massiveness and energy, has probably no psychical significance, I find myself unable to agree with him.
  • Change Date: 13 APR 2003 at 21:01:02

    Father: John James STRUTT b: 30 JAN 1796
    Mother: Clara Elizabeth La Touche VICARS

    Marriage 1 Evelyn Georgiana Mary BALFOUR b: BEF 1847
    • Married: 19 JUL 1871
    1. Has No Children Robert John STRUTT b: 28 AUG 1875
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