"No cyclic process is possible whose sole result is a flow of heat from a single reservoir and the performance of equivalent work."
"It is impossible by means of inanimate material agency to derive a mechanical effect from a portion of matter by cooling it below the temperature of the coldest surrounding bodies." [Source]
"There is at present in the material world a universal tendency to the dissipation of mechanical energy." [Source]
"Thus we have the sober scientific certainty that the heavens and earth shall 'wax old as doth a garment,' and that this slow progress must gradually, by natural agencies which we see going on under fixed laws, bring about circumstances in which 'the elements shall melt with fervent heat.' With such views forced upon us by the contemplation of dynamical energy and its laws of transformation of dead matter, dark indeed would be the prospects of the human race if unillumined by that light which reveals 'new heavens and a new earth.'" [Good Words, 1862]
"Although mechanical energy is indestructible, there is a universal tendency to its dissipation, which produces throughout the system a gradual augmentation and diffusion of heat, cessation of motion and exhaustion of the potential energy of the material Universe" [Source]
"Any restoration of mechanical energy, without more than an equivalent of dissipation, is impossible in inanimate material processes, and is probably never effected by means of organized matter, either endowed with vegetable life, or subjected to the will of an animated creature." [Source]
"Science is bound, by the everlasting vow of honour, to face fearlessly every problem which can be fairly presented to it." [Source]
"There cannot be a greater mistake than that of looking superciliously upon practical applications of science. The life and soul of science is its practical application…" [PLA, vol. 1, "Electrical Units of Measurement", May 3, 1883]
"Scientific wealth tends to accumulate according to the law of compound interest. Every addition to knowledge of the properties of matter supplies [the physical scientist] with new instrumental means for discovering and interpreting phenomena of nature, which in their turn afford foundations of fresh generalisations, bringing gains of permanent value into the great storehouse of [natural] philosophy." ["Presidential address to British Association", 1871]
"You can understand perfectly, if you give your mind to it"
"This time next year,—this time ten years,—this time one hundred years,—probably it will be just as easy as we think it is to understand that glass of water, which now seems so plain and simple. I cannot doubt but that these things, which now seem to us so mysterious, will be no mysteries at all; that the scales will fall from our eyes; that we shall learn to look on things in a different way—when that which is now a difficulty will be the only commonsense and intelligible way of looking at the subject." ["Presidential Address to the Institution of Electrical Engineers", 1889]
"When you are face to face with a difficulty, you are up against a discovery."
"The more you understand what is wrong with a figure, the more valuable that figure becomes."
"I am never content until I have constructed a mechanical model of the subject I am studying. If I succeed in making one, I understand; otherwise I do not." [BL]
"There is one thing I feel strongly in respect to investigation in physical or chemical laboratories—it leaves no room for shady, doubtful distinctions between truth, half-truth, whole falsehood. In the laboratory everything tested or tried is found true or not. Every result is true. Nothing not proved true is a result;—there is no such thing as doubtfulness. The search for absolute and unmistakable truth is promoted by laboratory work in a manner beyond all conception." [PLA, vol. 2, "The Bangor Laboratories"]
"When we look through the little universe that we know, and think of the transmission of electrical force and of the transmission of magnetic force and of the transmission of light, we have no right to assume that there may not be something else that our philosophy does not dream of." [BL, Lecture IV.]
"There is nothing new to be discovered in physics now, All that remains is more and more precise measurement."
"X-rays will prove to be a hoax."
When asked if he leaned toward the acceptance of any particular theory of gravitation: "No, no, no, I accept neither theory, I accept no theory of gravitation. Present science has no right to attempt to explain gravitation. We know nothing about it. We simply know nothing about it." [Quoted in Invisible Light (1900) by George Woodward Warder]
"By taking the gravity of a constant mass for the unit of force it makes the unit of force greater in high than in low altitudes. In reality, the standards of weight are masses, not forces. They are employed primarily in commerce for the purpose of measuring out a definite quantity of matter; not an amount of matter which shall be attracted to the earth with a given force." [PMD]
"My scientific sympathy and alliance with him [George FitzGerald] have greatly ripened during the last six or seven years over the undulatory theory of light and the aether theory of electricity and magnetism." [Quoted in The Scientific Writings of the Late George Francis Fitzgerald by Fitzgerald & Joseph Larmor]
"In the present state of physical science, therefore, a question of extreme interest arises: Is there any principle on which an absolute thermometric scale can be founded?" [Source]
"Blow a soap bubble and observe it. You may study it all your life and draw one lesson after another in physics from it."
"All the properties of matter are so connected that we can scarcely imagine one thoroughly explained, without our seeing its relation to all the others; without, in fact, having the explanation of all." [PLA, vol. 1, "Constitution of Matter"]
"From twenty to twenty-five years ago, I had no belief in the reality of this [Ampère's] theory; but I did not then know that motion is the very essence of what has hitherto been called matter." [From 1872, quoted in A History of European Thought in the Nineteenth Century (1912) by John Theodore]
"It seems to me that there must be something in this molecular hypothesis and that as a mechanical symbol, it is certainly not a mere hypothesis, but a reality." [BL]
[Mechanical models of molecules are more a] "help or corrective to brain sluggishness than a means of observation or discovery." [BL]
"Belief that no other theory of matter is possible is the only ground for anticipating that there is in store for the world another beautiful book to be called Elasticity, a Mode of Motion." ["Elasticity Viewed as Possibly a Mode of Motion", 1881]
"Imagine a globe of water or glass, as large as a football, to be magnified up to the size of the earth, each constituent molecule being magnified in the same proportion, the magnified structure would be more coarse-grained than a heap of shot, but probably less coarse-grained than a heap of footballs." ["The Size of Atoms", Nature, 1883-07-19]
"Diagrams and wire models were shown to the Society to illustrate knotted or knitted vortex atoms, the endless variety of which is infinitely more than sufficient to explain the varieties and allotropies of known simple bodies and their mutual affinities." [Source]
"The assumption of atoms can explain no property of body which has not previously been attributed to the atoms themselves." [Quoted in Eclectic Magazine, 1876]
"Vortices of pure energy can exist and, if my theories are right, can compose the bodily form of an intelligent species." [MPP]
Of the Vortex nature of Atoms: "It is only a dream."
"I cannot think that that quality of matter in space—magnetisation—which produces such a prodigious effect upon a piece of metal, can be absolutely without any—it is certainly not without any—effect whatever on the matter of a living body; and that it can be absolutely without any perceptible effect whatever on the matter of a living body placed there, seems to me not proved even yet, although nothing has been found." [Source]
"I firmly believe in an electromagnetic theory of light, and that when we understand electricity and magnetism and light we shall see them all together as parts of a whole. But I want to understand light as well as I can, without introducing things that we understand even less of. That is why I take plain dynamics. I can get a model in plain dynamics; I cannot in electromagnetics." [TLWT]
"We know that light is propagated like sound through pressure and motion."
[The phenomena of light] "can be explained without going beyond the elastic-solid theory. We have now our answer: every thing non-magnetic; nothing magnetic" [BL]
"It is absolutely certain that there is a definite dynamical theory for waves and light, to be enriched not abolished by electromagnetic theory." [BL]
[Maxwell] "makes a model that does all the wonderful things that electricity does in inducing currents, &c., and there can be no doubt that a mechanical model of that kind is immensely instructive and is a step towards a definite theory of electromagnatism."
"I never satisfy myself until I can make a mechanical model of a thing. If I can make a mechanical model I can understand it. As long as I cannot make a mechanical model all the way through I cannot understand; and that is why I cannot get the electromagnetic theory ..... But I want to understand light as well as I can, without introducing things that we understand even less of. That is why I take plain dynamics. I can get a model in plain dynamics; I cannot in electromagnetics" [BL]
"It is mere nihilism, having no part or lot in Natural Philosophy, to be contented with two formulas for energy, electromagnetic and electrostatic, and to be happy with a vector and delighted with a page of symmetrical formulas. … I have not had a moment's peace or happiness in respect to electromagnetic theory since Nov. 28 1846. All this time I have been liable to fits of ether dipsomania, kept away at intervals only by rigorous abstention of thought on the subject." [Remark to FitzGerald, 1896-04-09, TLWT, vol. 2]
"We can conceive that electricity itself is to be understood as not an accident, but an essence of matter. Whatever electricity is, it seems quite certain that electricity in motion is heat; and that a certain alignment of axes of revolution in this motion is magnetism."
[Electricity, heat, and magnetism are] "all by one and the same dynamical action." ["On Atmospheric Electricity", 1884]
"… Space is continuously occupied by an incompressible frictionless fluid acted on by no force, and that material phenomena of every kind depend solely on motions created in the fluid." [TRSE, vol. 25, 1869, pg. 217-260, "On Vortex Motion"]
[Faraday's] "attention was not directed to look for Hertz sparks, or probably he might have found them in the interior. Edison seems to have noticed something of the kind in what he called 'etheric force.' His name 'etheric' may thirteen years ago have seemed to many people absurd. But now we are all begining to call these inductive phenomena 'etheric.'"
"… it is no greater mystery at all events than the shoemakers' wax." [BL]
[Is there any matter not subject to the law of gravitation?] "I think that I may say with absolute decision that there is. We are all convinced… that ether is matter." [BL]
"It has occurred to me that, without contravening anything we know from observation of nature, we may simply deny the scholastic axiom that two portions of matter cannot jointly occupy the same space, and may assert, as an admissible hypothesis, that ether does occupy the same space as ponderable matter." [BL, ap. A, "Nineteenth-Century Clouds…"]
"We all know how Faraday made himself a cage six feet in diameter, hung it up in mid-air in the theatre of the Royal Institution, went into it, and, as he said, lived in it and made experiments. It was a cage with tin-foil hanging all round it; it was not a complete metallic enclosing shell, Faraday had a powerful machine working in the neighborhood, giving all varieties of gradual working-up and discharges by 'impulsive rush'; and whether it was a sudden discharge of ordinary insulated conductors, or of Leyden jars in the neighborhood outside the cage, or electrification and discharge of the cage itself, he saw no effects on his most delicate gold-leaf electroscopes in the interior. His attention was not directed to look for Hertz sparks, or probably he might have found them in the interior. Edison seems to have noticed something of the kind in what he called the etheric force. His name 'etheric' may, thirteen years ago, have seemed to many people absurd. But now we are all beginning to call these inductive phenomena 'etheric.'" [At a meeting of the Institution of Electrical Engineers, London, 1889-05-16, quoted in "Edison His Life and Inventions" by Frank Lewis Dyer]
"To measure is to know."
"If you can not measure it, you can not improve it."
"In physical science the first essential step in the direction of learning any subject is to find principles of numerical reckoning and practicable methods for measuring some quality connected with it. I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind; it may be the beginning of knowledge, but you have scarcely in your thoughts advanced to the state of Science, whatever the matter may be." [PLA, vol. 1, "Electrical Units of Measurement", 1883-05-03]
"You, in this country, are subjected to the British insularity in weights and measures; you use the foot, inch and yard. I am obliged to use that system, but must apologize to you for doing so, because it is so inconvenient, and I hope Americans will do everything in their power to introduce the French metrical system. … I look upon our English system as a wickedly, brain-destroying system of bondage under which we suffer. The reason why we continue to use it, is the imaginary difficulty of making a change, and nothing else; but I do not think in America that any such difficulty should stand in the way of adopting so splendidly useful a reform." [Source]
"The true measure of a man is what he would do if he knew he would never be caught."
"Mathematics is the only good metaphysics."
"Nothing can be more fatal to progress than a too confident reliance on mathematical symbols; for the student is only too apt to take the easier course, and consider the formula not the fact as the physical reality."
"The fact that mathematics does such a good job of describing the Universe is a mystery that we don't understand. And a debt that we will probably never be able to repay."
"Do not imagine that mathematics is hard and crabbed, and repulsive to common sense. It is merely the etherealisation of common sense." [Source]
S. P. Thompson: "Once when lecturing in class he [the Lord Kelvin] used the word 'mathematician' and then interrupting himself asked his class: 'Do you know what a mathematician is?' Stepping to his blackboard he wrote upon it: integral from - infinty to + infinity of exp(-x^2)dx = sqrt(pi). Then putting his finger on what he had written, he turned to his class and said, 'a mathematician is one to whom that is as obvious as that twice two makes four is to you.'" [TLWT]
"There can be but one opinion as to the beauty and utility of this analysis of Laplace; but the manner in which it has been hitherto presented has seemed repulsive to the ablest mathematicians, and difficult to ordinary mathematical students."
"Quaternions came from Hamilton after his really good work had been done; and though beautifully ingenious, have been an unmixed evil to those who have touched them in any way, including Maxwell."
"Fourier's Theorem is not only one of the most beautiful results of modern analysis, but it is said to furnish an indispensable instrument in the treatment of nearly every recondite question in modern physics."
"Fourier is a mathematical poem." [TNP]
"… after I had attended in 1839 Nichol's… class, I had become filled with the utmost admiration for the splendour and poetry of Fourier. Nichol was not a mathematician and did not profess to have really read Fourier, but he was capable of perceiving his greatness and of understanding what he was driving at, and of making us appreciate it. I asked Nichol if he thought I could read Fourier. He replied 'perhaps'. He thought the book a work of most transcendent merit. So on the 1st of May the very day when the prizes were given, I took Fourier out of the University Library, and in a fortnight I had mastered it—gone right through it."
[The vector] "has never been of the slightest use to any creature."
"With three parameters, I can fit an elephant."
"A single curve, drawn in the manner of the curve of prices of cotton, describes all that the ear can possibly hear as the result of the most complicated musical performance…. That to my mind is a wonderful proof of the potency of mathematics."
"I have no satisfaction in formulas unless I feel their numerical magnitude."
"I call any geometrical figure, or any group of points, chiral, and say it has chirality, if its image in a plane mirror, ideally realized, cannot be brought to coincide with itself" [BL]
"Radio has no future."
"Wireless [telegraphy] is all very well but I'd rather send a message by a boy on a pony!" [Quoted in My Father, Marconi by Degna Marconi]
[After having arrived in America by ship, whence he had sent two messages by wireless telegraphy and received in return one:] "The wireless telegraphy is one of the most wonderful inventions the world has ever seen. I think it will be of great commercial use some day and as I have seen it demonstrated on the ship in which I have just arrived I can say that it is very marvelous indeed." [BDE 1902-04-19, pg. 20, "Lord Kelvin Here"]
"A most remarkable invention. I believe that Marconi will soon establish Transatlantic wireless telegraphy on a firm commercial basis." [BDE 1902-05-11, pg. 8, "Marconigrams"]
"I have given careful consideration to this subject and I do not believe the shareholders of your company need be alarmed at the prospect of wireless telegraphy." [At a meeting of the Anglo-American Telephone Company on Aug. 1, 1902. BDE 1902-08-03, pg. 39, "Wireless System Not Feared"]
[The Faure "box of electricity"] "It is going to be a most valuable, practical affair—as valuable as water-cisterns to people whether they had or had not systems of water-pipes and water-supply."
"The telephone is one of the most interesting inventions that has ever been made in the history of science."
"The things that were called telephones before Bell were as different from Bell's telephone as a series of hand-claps are different from the human voice. They were in fact electrical claps; while Bell conceived the idea—THE WHOLLY ORIGINAL AND NOVEL IDEA—of giving continuity to the shocks, so as to perfectly reproduce the human voice."
[Speaking of the Telephone] "It is the wonder of wonders" and "the greatest marvel hitherto achieved by the electric telegraph."
"The steam engine has given more to science than science has given to the steam engine."
"The steam-engine is passing away."
[It is not] "utterly chimerical to think of wind superseding coal in some places for a very important part of its present duty—that of giving light."
Writing to Niagara Falls Power Company: "Trust you will avoid the gigantic mistake of alternating current."
"I have just come from Niagara Falls. I saw something there that I had never seen before; in fact, I regard it as the most interesting sight I have witnessed in America on my present trip. At the Atmosperic Products Company's works I saw the fixation of nitrogen. It has been the dream of the electro-chemical workers for years to produce results that should be of commercial value, and that result has not been accomplished. Over a century ago the discovery was made that nitric acid could be manufactured from air, but not untill the plant was established at Niagara Falls has the discovery been utilized in a practical way." [BDE 1902-09-14, pg. 35, "Newest Marvel of Science is to Transmute the Air into Food"]
"I look forward to the time when the whole water from lake Erie will find its way to the lower level of Lake Ontario, through machinery, doing more good for the world than that great benefit which we now possess in the contemplation of the splendid scene which we have presented before us at the present by the waterfall. … I do not hope that our children's children will ever see the Niagara cataract." [The Washington Post, 1897-11-18, pg. 6, "Solence Run to Folly"]
"As the demand goes on increasing, so the amount of horse-power developed will increase, until the whole water power of Niagara will be used for doing mechanical work." [Toronto Daily Mail and Empire, 1897-11-19]
"Beautiful as that wonderful work of nature [Niagara] is, it would be more beautiful still if those waters fell upon turbine wheels every one of which was turning the wheels of industry." [TLWT, vol. 2, p. 1168]
"This leads me to remark how much science, even in its most lofty speculations, gains in return for benefits conferred by its application to promote the social and material welfare of man.Those who periled and lost their money in the original Atlantic Telegraph were impelled and supported by a sense of grandeur of their enterprise, and of the world-wide benefits which must flow from its success; they were at the same time not unmoved by the beauty of the scientific problem directly presented to them; but they little thought that it was the immediately, through their work, that the scientific world was to be instructed in a long-neglected and discredited fundamental electric discovery of Faraday's…" [PLA, vol. 2, p. 161]
"Judged by its results in benefiting the public, both by stimulating inventors and by giving a perseveringly practical turn to their labors, the American patent-law must be admitted to be most successful, and the beneficence of its working was very amply illustrated throughout the American region of the Exhibition, where indeed it seemed that every good thing deserving a patent was patented. I asked one inventor of a very good invention, 'Why do you not patent in England?' the reply was, 'The conditions in England are too onerous.' England undoubtedly loses much of the benefit which might be had from the inventiveness of Englishmen, through the want, in English patent-law, of encouragement and protection to inventors unsupported by capitalists." [Our Patent-System, and What We Owe to It, Richardson, James. Off site source]
"Photography in natural colors will soon be an established fact, although it will necessitate a lot of study to get it perfected." [The New York Times, May 11, 1902.]
Speaking of the automobile: "Of course locomotorism has 'come to stay,' as the jargon of the day puts it. And London of all places ought to welcome it. The crowded state of the London streets has for long been a problem with which no such body as the London county council seems competent to grapple. Evolution will do it. A motor omnibus occupies scarcely more than half the space that is necessary for a horsed omnibus. Therefore the exchange from horsed vehicles to horseless will halve the traffic. Halve the traffic in London, and the greatest problem of the metropolis is solved for a generation at least. And the same is true of New York." [Said to a reporter of the New York Commercial Advertiser. Quoted in the Waterloo Daily Reporter for May 5, 1902, p.3.]
"I can state flatly that heavier than air flying machines are impossible." [Note: this quote is widely circulated, especially among self-help gurus, motivational speakers, and the like, but a newspaper archive search and Google book search shows no hits published during Kelvin's lifetime.]
"I have not the smallest molecule of faith in aerial navigation other than ballooning or of the expectation of good results from any of the trials we hear of … I would not care to be a member of the Aeronautical Society." [Source]
"The air-ship, on the plan of those built by Santos-Dumont, is a delusion and a snare. A gas balloon, paddled around by oars, is an old idea, and can never be of any practical use. Some day, no doubt, some one will invent a flying machine that one will be able to navigate without having to have a balloon attachment. But the day is a long way off when we shall see human beings soaring around like birds." [TLWT, vol. 2, p. 1168]
"They never will be able to use dirigible balloons as a means of conveying passengers from place to place. There never was and never can be any commercial value to any such affair. It is all a delusion and a snare. Santos-Dumont is a very bright young man, but an air ship as planned by him is not practicable." [Said to reporters after having arrived in New York on April 19, 1902. Quoted in the New York Times, p.2, the next day.]
Also see this 1902 interview.
"Within a finite period of time past, the earth must have been, and within a finite period of time to come the earth must again be, unfit for the habitation of man as at present constituted, unless operations have been, or are to be performed, which are impossible under the laws to which the known operations going on at present in the material world are subject." [Source]
"A great reform in geological speculation seems now to have become necessary." [Source]
"It is quite certain that a great mistake has been made—that British popular geology at the presents time is in direct opposition to the principles of Natural Philosophy." [Source]
"We can see, therefore, that there are many attributes of movement, displacement, and deformation which can be considered independently of force, mass, chemical composition, elasticity, heat, magnetism and electricity; and it is of greatest use to science for such properties to be considered as a first step."
"Physicists are not wholly incapable of appreciating geological difficulties."
"It was only by sheer force of reason that geologists have been compelled to think otherwise, and to see that there was a definite beginning, and to look forward to a definite end, of this world as an abode fitted for life."
"It would be a very wonderful, but not an absolutely incredible result, that volcanic action has never been more violent on the whole than during the last two or three centuries: but it is as certain that there is now less volcanic energy in the whole earth than there was a thousand years ago, as it is that there is less gunpowder in the "Monitor" after she has been seen to discharge shot and shell, whether at a nearly equable rate or not, for five hours without receiving fresh supplies, than there was at the beginning of the action. Yet the truth has been ignored or denied by many of the leading geologists of the present day." [Source]
[The Uniformitarian theory—as proposed by Sir Charles Lyell—that the earth's internal heat is due to the chemical production of thermo-electric processes that in turn decompose the chemical products forming a perpetual cycle] "violates the principles of natural philosophy in exactly the same manner, and to the same degree, as to believe that a clock constructed with a self-winding movement may fulfil the expectations of its ingenious inventor by going for ever."
"But I think we may with much probability say that the consolidation [of the earth] cannot have taken place less than 20,000,000 years ago, or we should have more underground heat than we actually have, nor more than 400,000,000 years ago, or we should not have so much as the least observable underground increment of temperature." [Source]
"During the thirty-five years which have passed since I gave this wide-ranged estimate [of 20-400 million years] experimental investigation has supplied much of the knowledge then wanting regarding the thermal properties of rocks to form a closer estimate of the time which has passed since the consolidation of the earth, we have now good reason for judging that it was more than 20,000,000 and less than 40,000,000 years ago, and probably much nearer 20 than 40." [AEAFL]
"By an elaborate piece of mathematical bookkeeping I have worked out the problem of the conduction of heat outward from the earth, with specific heat increasing up to the melting point as found by Rucker and Roberts-Austen and by Barns, but with the conductivity assumed constant; and, by taking into account the augmentation of melting temperature with pressure in a somewhat more complete manner than that adopted by Mr. Clarence King, I am not led to differ much from his estimate of 24,000,000 years. But until we know something more than we know at present as to the probable diminution of thermal conductivity with increasing temperature, which would shorten the time since consolidation, it would be quite inadvisable to publish any closer estimate." [AEAFL]
"All these reckonings of the history of underground heat, the details of which I am sure you do not wish me to put before you at present, are founded on the very sure assumption that the material of our present solid earth all round its surface was at one time a white-hot liquid." [AEAFL]
"What then are we to think of such geological estimates as [Darwin's] 300,000,000 years for the 'denudation of the Weald'?" [Source]
In denouncing the great omission in modern education of not teaching the use of globes, for which he held Huxley partly responsible: "No plane map could give any one a notion of the world; and with our Empire every English child ought to be shown something of its extent. … I have a conscientious scruple against paying for education in geography without the use of the globes, and shall not pay the proportionate part of the rate." [TLWT]
"Now, if the sun is not created a miraculous body, to shine on and give out heat forever, we must suppose it to be a body subject to the laws of matter (I do not say there may not be laws which we have not discovered) but, at all events, not violating any laws we have discovered or believe we have discovered, we should deal with the sun as we should with any large mass of molten iron, silicon or sodium." [Source]
"It seems as if we may also be forced to conclude that the supposed connection between magnetic storms and sunspots is unreal, and that the seeming agreement between the periods has been mere coincidence."
"It would, I think, be exceedingly rash to assume as probable anything more than twenty million years of the sun's light in the past history of the earth, or to reckon on more than five or six million years of sunlight for time to come."
"That some form of the meteoric theory is certainly the true and complete explanation of solar heat can scarcely be doubted, when the following reasons are considered: (1) No other natural explanation, except by chemical action, can be conceived. (2) The chemical theory is quite insufficient, because the most energetic chemical action we know, taking place between substances amounting to the whole sun's mass, would only generate about 3,000 years' heat. (3) There is no difficulty in accounting for 20,000,000 years' heat by the meteoric theory." [Source]
"It seems, therefore, on the whole most probable that the sun has not illuminated the earth for 100,000,000 years, and almost certain that he has not done so for 500,000,000 years. As for the future, we may say, with equal certainty, that inhabitants of the earth cannot continue to enjoy the light and heat essential to their life, for many million years longer, unless sources now unknown to us are prepared in the great storehouse of creation." [Source]
"Many of our supposed thousand million stars, perhaps a great majority of them, may be dark bodies. … It is nevertheless probable that there may be as many as 1000 million stars within the distance [of a sphere of radius 3.09×1016 kilometres]; but many of them may be extinct and dark, and nine-tenths of them though not all dark may be not bright enough to be seen by us at their actual distances." [BL, #xvi]
"What would you think of a Universe in which you could travel one, ten, or a thousand miles, or even to California, and then find it came to an end? Even if you were to go millions and millions of miles, the idea of coming to an end is still incomprehensible." [Source]
"When an animal works against a resisting force, there is not a conversion of heat into mechanical effect, but the full thermal equivalent of the chemical forces is never produced; in other words, the animal body does not act as a thermodynamic engine, and very probably the chemical forces produce the external mechanical effects through electrical means." [Source]
"Consciousness teaches every individual that they are, to some extent, subject to the direction of his will. It appears therefore that animated creatures have the power of immediately applying to certain moving particles of matter within their bodies, forces by which the motions of these particles are directed to produce derived mechanical effects." [Source]
"It is, however, conceivable that animal life might have the attribute of using the heat of surrounding matter, at its natural temperature, as a source of energy for mechanical effect."
"The influence of animal or vegetable life on matter is infinitely beyond the range of any scientific inquiry hitherto entered on. Its power of directing the motions of moving particles, in the demonstrated daily miracle of our human free will, and in the growtli of generation after generation of plants from a single seed, are infinitely different from any possible result of the fortuitous concourse of atoms; and the fortuitous concourse of atoms is the sole foundation in philosophy on which can be founded the doctrine that it is impossible to derive mechanical effect from heat otherwise than by taking heat from a body at a higher temperature, converting at most a definite proportion of it into mechanical effect, and giving out the whole residue to matter at a lower temperature." [Quoted in the Annual Report of the Board of Regents of the Smithsonian Institution (1898)]
"Modern biologists are coming, I believe, once more to a firm acceptance of something beyond mere gravitational, chemical, and physical forces; and that unknown thing is a vital principle." [Source]
"The limitations of geological periods, imposed by physical science, cannot, of course, disprove the hypothesis of transmutation of species; but it does seem sufficient to disprove the doctrine that transmutation has taken place through 'descent with modification by natural selection.'" ["Of Geological Dynamics", 1869]
"Hence and because we all confidently believe that there are at present, and have been from time immemorial, many worlds of life besides our own, we must regard it as probable in the highest degree that there are countless seed-bearing meteoritic stones moving about through space." [Source]
"The hypothesis that life originated on this earth through moss-grown fragments from the ruins of another world may seem wild and visionary; all I maintain is that it is not unscientific." [Source]
"I need scarcely say that the beginning and maintenance of life on earth is absolutely and infinitely beyond the range of all sound speculation in dynamical science. The only contribution of dynamics to theoretical biology is absolute negation of automatic commencement or automatic maintenance of life."
"Mathematics and dynamics fail us when we contemplate the Earth, fitted for life but lifeless, and try to imagine the commencement of life upon it. This certainly did not take place by any action of chemistry, or electricity, or crystalline grouping of molecules under the influence of force, or by any possible kind of fortuitous concourse of atoms. We must pause, face to face with the mystery and miracle of creation of living creatures."
"A very ancient speculation still clung to by many naturalists (so much so, that I have a choice of modern terms to quote in expressing it), supposes that, under meteorological conditions very different from the present, dead matter may have run together or crystallized or fermented into 'germs of life,' or 'organic cells,' or 'protoplasm.' But science brings a vast mass of inductive evidence against this hypothesis of spontaneous generation, as you have heard from my predecessor in the presidential chair. Careful enough scrutiny has, in every case up to the present day, discovered life as antecedent to life. Dead matter cannot become living without coming under the influence of matter previously alive. This seems to me as sure a teaching of science as the law of gravitation." [Source]
"The modern medical man must be a scientific man, and, what is more, he must be a philosopher. The fundamental studies of medicine are of a strictly materialistic kind, but they belong to a different world from the world which constitutes their main subject—the world of life. Let it not be imagined that any hocuspocus of electricity or viscous fluids will make a living cell. Splendid and interesting work has recently been done in what was formerly called organic chemistry, a great French chemist taking the lead. This is not the occasion for a lecture on the borderland between what is called organic and what is called inorganic; but it is interesting to know that materials belonging to the general class of foodstuffs, such as sugar, and what might be also called a foodstuff, alcohol, can be made out of the chemical elements. But let not youthful minds be dazzled by the imaginings of the daily newspapers that because Berthelot and others have thus made foodstuffs they can make living things, or that there is any prospect of a process being found in any laboratory for making a living thing, whether the minutest germ of bacteriology or anything smaller or greater. There is an absolute distinction between crystals and cells. Anything that crystallises may be made by the chemist. Nothing approaching to the cell of a living creature has ever yet been made. The general result of an enormous amount of exceedingly intricate and thoroughgoing investigation by Huxley and Hooker and others of the present age, and by some of their predecessors in both the nineteenth and eighteenth centuries, is that no artificial process whatever can make living matter out of dead. This is vastly beyond the subject of the chemical laboratory, vastly beyond my own subject of physics or of electricity—beyond it in depth of scientific significance and in human interest." ["Speaking at St. George's Hospital Medical School on Friday last", Nature, November 3, 1904.]
"I feel profoundly convinced that the argument of design has been greatly too much lost sight of in recent zoological speculations. Reactions against the frivolities of teleology, such as are to be found, not rarely, in the notes of the learned commentators on Paley's 'Natural Theology,' has, I believe, had a temporary effect in turning attention from the solid and irrefragable argument so well put forward in that excellent old book. But overwhelmingly strong proofs of intelligent and benevolent design lie all around us, and if ever perplexities, whether metaphysical or scientific, turn us away from them for a time, they come back upon us with irresistible force, showing to us through nature the influence of a free will, and teaching us that all living beings depend on one ever-acting Creator and Ruler." [Source]
"I cannot admit that, with regard to the origin of life, science neither affirms nor denies Creative Power. Science positively affirms Creative Power. It is not in dead matter that we live and move and have our being, but in the creating and directing Power which science compels us to accept as an article of belief." [Source]
"… Creative Power is the only feasible answer to the origin of life from a scientific perspective."
"Overwhelming strong proofs of intelligent and benevolent design lie around us."
"I believe that the more thoroughly science is studied, the further does it take us from anything comparable to atheism." [TLWT]
"The more thoroughly I conduct scientific research, the more I believe that science excludes atheism."
"The atheistic idea is so nonsensical that I do not see how I can put it in words." [Source]
"Do not be afraid of being free thinkers. If you think strongly enough you will be forced by science to the belief in God, which is the foundation of all religion. You will find science not antagonistic but helpful to religion." [Source]
"The mystery of radium, no doubt we shall solve it one day; but the freedom of the will, that is a mystery of another kind." [TLWT]
"The question of usefulness or the reverse of tobacco or alcohol is one of health, and to be answered by medical men, if they can. It seems to me that neither is of the slightest consequence as a stimulus or help to intellectual efforts, but that either may be used without harm or the reverse if in small enough quantities, so as not to hurt the digestion." [Feb. 13, 1882. Quoted in Study and Stimulants: Or The Use of Intoxicants and Narcotics in Relation to Intellectual Life, 1883, Alfred Arthur Reade]
Asked by spiritualist William T. Stead to interest himself in "borderland" subjects, Kelvin replied: "I have nothing to do with borderland. I believe that nearly everything in hypnotism and clairvoyance is imposture, and the rest bad observation." [Quoted in Spiritualism: The Open Door to the Unseen Universe, 1908, James Robertson]
"One half of hypnotism is fraud and the rest bad observation." [Quoted in Powers That Be, 1935, Alexander Cannon]
"A university is a place that fits some men for earning a livelihood, and that makes life better worth living for all men." [TLWT, vol. 2, p. 1168]
"I have been a student of the University of Glasgow fifty-five years to-day, and I hope to continue a student of the University as long as I live."
"One word characterized the most strenuous of the efforts for the advancement of science that I have made perseveringly during fifty-five years; that word is FAILURE. I know no more of electric and magnetic force, or of the relation between ether, electricity, and ponderable matter, or of chemical affinity, than I knew and tried to teach my students of natural philosophy fifty years ago in my first session as Professor. Something of sadness must come of failure; but in the pursuit of science, inborn neccessity to make the effort brings with it much of the certaminis gaudia, and saves the naturalist from being wholly miserable, perhaps even allows him to be fairly happy in his daily work." [Source]
"To live among friends is the primary essential of happiness." [Source]
On Anglo-Saxon unification: "We have shown that it is possible to get on well together under separate flags, but I wish we were all under one flag and under one government." [TLWT, vol. 2, p. 1168]
"War is a relic of babarism probably destined to become as obsolete as duelling."
"Large increases in cost with questionable increases in performance can be tolerated only in race horses and fancy women."
On amphibian levitation: "It will probably be impossible ever to observe this phenomenon, on account of the difficulty of getting a magnet strong enough, and a diamagnetic substance sufficiently light, as the [magnetic] forces are excessively feeble."
"A boy should have learnt by the age of twelve to write his own language with accuracy and some degree of elegance; he should have a reading knowledge of French, should be able to translate Latin and easy Greek authors and should have some acquaintance with German."
"If only we had thirty hours in a day instead of twenty-four, we might get some of our work done." [Quoted in his obituary in the New York Times.]
LORD KELVIN'S QUICK EAR
How the Great Scientist Located an Inattentive Student.
Lord Kelvin once surprised his class by the quick and amusing manner in which he solved a problem on "sound," says Mainly About People. In the midst of an experiment Lord Kelvin had ceased lecturing and was silently watching, along with most of the students, the progress of an experiment. There was a dead silence, which was suddenly and rudely broken by the sound of a marble, which an inattentive pupil has dropped, and which continued to roll and drop, drop, drop down all the tiers of benches till it reached the ground floor. Meanwhile Lord Kelvin had quickly turned round and observed where the marble emerged on to the floor. He counted back the number of times he had heard it drop and then announced:
"Mr. X— of the seventh tier, you may report to me after the lecture."
The eminent scientist had correctly spotted the culprit.
[BDE, 1900-12-28, pg. 4]
One day when experimenting with a device—made of piano wire and a stoppered glass tube—for measuring nautical depths, The Lord Kelvin was interrupted by James Prescott Joule. "What are you doing?" he asked, amazed at the great lengths of piano wire. "Sounding," said The Lord. "What note?" asked Joule. "The deep C," replied The Lord. [MOM]
Once during a sermon on the Second Law of Thermodynamics and the Entropic Heat Death of the Universe, the Lord Kelvin pronounced that our world would end in about 20 billion years when the sun's fuel expired. An elderly woman in the congregation interrupted Him and anxiously asked: "How long did you say?". The Lord Kelvin replied "20 billion years". The woman sighed, "Thank You Lord, I thought You said 20 million!".
While musing upon the subject of thermodynamics one day, Lord Kelvin suddenly realized that his wife was discussing plans for an afternoon excursion. "At what time," he asked, glancing up, "does the dissipation of energy begin?" [MOM]
The famed physicist William Thomson (later Lord Kelvin) was a professor of natural philosophy at Glasgow University for some fifty years. Unable to meet his class one day, he posted a note on the door of his lecture room: "Professor Thomson," it said, "will not meet his classes today." As a joke, some of his mischievous students erased the "c," leaving a message reading: "Professor Thomson will not meet his lasses today." The following day when the pranksters assembled in anticipation of the effect of their joke, they were chagrined to find that the professor had outwitted them. The note was now found to read: "Professor Thomson will not meet his asses today." [Cyrus Northrup, University of Washington Address, November 2, 1908]
When Lord Kelvin was a professor at Glasgow University, he often left the teaching to his assistant, Dr. Day. One morning, as he entered the class to deliver the last of a course of lectures, Day was amused to find a note which Kelvin had left on the blackboard: "Work while it is yet Day, for the Knight cometh when no man can work." [MOM]
At Glasgow University one day, Lord Kelvin found himself delivering a lecture in a room directly beneath another colleague whose students, at the end of the lecture, showed their appreciation in the customary manner—by stamping vigorously on the floor. "Ah," Lord Kelvin remarked, as chucks of plaster fell from the ceiling, "I see Dr. Campbell's conclusions don't agree with my premises." [MOM]
As an undergraduate at Cambridge, William Thomson (later Lord Kelvin) thought he was certain to be named "Senior Wrangler"—the designation given to the student who received the highest score on the mathematical Tripos. After taking the exam, he asked his servant, to "run down to the Senate House and see who is Second Wrangler." The servant promtply returned with the answer: "You, sir!" [Mathematics: People, Problems, Results, D. M. Campbell and J. C. Higgins]
Lord Kelvin responded for Science, and in the course of his remarks he suggested that logic was the contribution of science to literature, and said that all the miseries of mankind, in politics at least, were due to bad logic. The trouble in South Africa was due, not to money or mines, but to bad logic and stupidity. (Hear, hear.) [At the Royal Societies' Club Annual Dinner, held 1900-06-21, as reported in The Daily News (London), 1900-06-22, p. 2]
Lord Kelvin, the eminent scientist, has not added to the mirthfulness of the nations by announcing that in four hundred years the oxygen now virtually free in our atmosphere will be used up, and the inhabitants of the earth will die of suffocation from carbonic acid gas. [The Washington Post, 1898-06-21, pg. 6, "Only 400 Years"]
Sooner or later my power system will have to be adopted in its entirety and so far as I am concerned it is as good as done. If I were ever assailed by doubt of ultimate success I would dismiss it by remembering the words of that great philosopher, Lord Kelvin, who after witnessing some of my experiments said to me with tears in his eyes: "I am sure you will do it." ["World System of Wireless Transmission of Energy" by Nikola Tesla, Telegraph and Telegraph Age, October 16, 1927]
"A Strange Proposal: We have heard of proposals which have been made under the most peculiar circumstances, and in the most peculiar ways, but Lord Kelvin, the English scientist, may be said to have made the most unique proposal of marriage on record. He had invented a simple method of marine signaling which was understood by Miss Crum, the young lady of his choice, and while touring on his yacht Lalla Rookh he sent her a message which read: 'Will you marry me?' to which Miss Crum answered: 'Yes.'" [The Daily Herald, 1903-12-03.]
(Abbreviated dates given in yyyy-mm-dd format.)
I'm working on better citations. If you know of the source for any of the uncited quotes above or have any corrections, please let me know. There is a chance that some of the uncited quotes are apocryphal.
If I have a copy or partial copy of the source, then I'll link to that. No anchor links, sorry; search that document to find the quote.
Some of the sources, such as PLA, are compilations of works that may have been published previously. With those, I'll try to give either the original publish date, or the volume/page from the compilation.