John Tyndall: Wikis


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John Tyndall

Born 2 August 1820 (1820-08-02)
Leighlinbridge, County Carlow, Ireland
Died 4 December 1893 (1893-12-05) (aged 73)
Hindhead, Surrey, England
Nationality British
Fields Physics
Institutions Royal Institution of Great Britain
Alma mater University of Marburg
Known for Atmosphere, physics education,
Tyndall effect, diamagnetism,
infrared radiation, Tyndallization

John Tyndall FRS (2 August 1820 – 4 December 1893) was a prominent 19th century physicist. His initial scientific fame arose in the 1850s from his study of diamagnetism. Later he studied thermal radiation, and produced a number of discoveries about processes in the atmosphere. Tyndall published seventeen books, which brought state-of-the-art 19th century experimental physics to a wider audience. From 1853 to 1887 he was professor of physics at the Royal Institution of Great Britain, where he became the successor to positions held by Michael Faraday.


Early years and education

Tyndall was born in Leighlinbridge, County Carlow, Ireland. His father was a local police constable and small landowner, descended from Gloucestershire emigrants who settled in southeast Ireland around 1670. Tyndall attended the local schools in County Carlow until his late teens, and was probably an assistant teacher near the end of his time there. Subjects learned at school notably included technical drawing and mathematics with some applications of those subjects to land surveying. He was hired as a draftsman by the government's land surveying & mapping agency in Ireland in his late teens in 1839, and moved to work for the same agency in England in 1842. In the decade of the 1840s, a railroad-building boom was in progress, and Tyndall's land surveying experience was valuable and in demand by the railroad companies. Between 1844 and 1847, he was lucratively employed in railroad construction planning.[1][2]

John Tyndall circa 1850

In 1847 Tyndall opted to become a mathematics teacher at a boarding school in Hampshire. Recalling this decision later, he wrote: "the desire to grow intellectually did not forsake me; and, when railway work slackened, I accepted in 1847 a post as master in Queenwood College."[3][4] Another recently-arrived young teacher at Queenwood was Edward Frankland, who had previously worked as a chemical laboratory assistant for the British Geological Survey. Frankland and Tyndall became good friends. On the strength of Frankland's prior knowledge, they decided to go to Germany to further their education in science. (Among other things, Frankland knew that certain German universities were ahead of any in Britain in experimental chemistry and physics. British universities were still focused on classics and mathematics and not laboratory science.) The pair moved to Germany in summer 1848 and enrolled at the University of Marburg, where Robert Bunsen was an influential teacher. Tyndall studied under Bunsen for two years.[5] Probably more influential for Tyndall at Marburg was Professor Hermann Knoblauch, with whom Tyndall maintained communications by letter for many years afterwards. Tyndall's Marburg dissertation was a mathematical analysis of screw surfaces in 1850 (under Friedrich Ludwig Stegmann). He stayed at Marburg for a further year doing research on magnetism with Knoblauch, including some months' visit at the laboratory of Knoblauch's main teacher, Gustav Magnus in Berlin. It is clear today that Bunsen and Magnus were among the very best experimental science instructors of the era. Thus, when Tyndall returned to live in England in summer 1851, he probably had as good an education in experimental science as anyone in England.

Early scientific work

Tyndall's early original work in physics was his experiments on magnetism and diamagnetic polarity, on which he worked from 1850 to 1856. His two most influential reports were the first two, co-authored with Knoblauch. One of them was entitled "The magneto-optic properties of crystals, and the relation of magnetism and diamagnetism to molecular arrangement", dated May 1850. The two described an inspired experiment, with an inspired interpretation. These and other magnetic investigations very soon made Tyndall known among the leading scientists of the day.[6] He was elected a Fellow of the Royal Society in 1852. In his search for a suitable research appointment, he was able to ask the longtime editor of the leading German physics journal (Poggendorff) and other prominent men to write testimonials on his behalf. In 1853, he attained the prestigious appointment of Professor of Natural Philosophy (Physics) at the Royal Institution in London, due in no small part to the esteem his work had garnered from Michael Faraday, then the leader of magnetic investigations at the Royal Institution.[7]

Main scientific work

Beginning in the late 1850s, Tyndall studied the action of radiant energy on the constituents of air, and it led him onto several lines of inquiry, and his original research results included the following:[8]

Tyndall's setup for measuring the radiant heat absorption of gases. (Click on image for a description).
Tyndall's bar breaker experiment to show the forces of thermal expansion
  • Tyndall explained the heat in the Earth's atmosphere in terms of the capacities of the various gases in the air to absorb radiant heat, a.k.a. infrared radiation. His measuring device, which used thermopile technology, was a significant early step in the history of absorption spectroscopy of gases.[9] He was the first to correctly measure the infrared absorptive powers of the gases nitrogen, oxygen, water vapour, carbon dioxide, ozone, methane, etc. He concluded that water vapour is the strongest absorber of radiant heat in the atmosphere and is the principal gas controlling air temperature. Absorption by the bulk of the other gases is negligible. Prior to Tyndall it was widely surmised that the Earth's atmosphere has a Greenhouse Effect, but he was first to prove it. The proof was that water vapor strongly absorbed infrared radiation.[10]
  • He contributed to establishing, as he put it in one of his tutorials, "the identity of light and radiant heat."[11] He consolidated and enhanced the work of James David Forbes, Hermann Knoblauch and others demonstrating that the principal properties of visible light can be reproduced for radiant heat, namely reflection, refraction, diffraction, polarization, depolarization, double refraction, and rotation in a magnetic field (Faraday effect).[12] He also devised demonstrations that advanced the question of how radiant heat is absorbed at the molecular level. That included demonstrations involving what he called calorescence, which is the conversion of infrared into visible light at the molecular level. He referred to infrared as "obscure radiation", "dark waves" or "ultra-red undulations", as the word "infrared" didn't start coming into use until the 1880s. Among his key laboratory tools were substances that are transparent to infrared and opaque to visible light; or vice versa. (Tyndall's main published research reports about radiant heat were republished as a 450-page collection in 1872. The collection contains more than 200 mentions of the name Professor Magnus. Tyndall and Magnus closely studied each other's radiant heat research during the 1860s.)
  • In the investigations on radiant heat in air it had been necessary to use air from which all traces of floating dust and other particulates had been removed.[13] A very sensitive way to detect particulates is to bathe the air with intense light. The scattering of light by particulate impurities in air and other gases, and in liquids, is known today as the Tyndall Effect or Tyndall Scattering.[14] In studying this scattering during the late 1860s Tyndall was a beneficiary of recent improvements in electric-powered lights. He also had the use of good light concentrators. He developed the nephelometer and turbidimeter and similar instruments that show properties of aerosols and colloids through concentrated light beams. Particulates suspended in air are visible to the naked eye in a darkened room with sunlight coming through a crack in the curtains. Mostly visibly that's light reflecting off large particulates which is not the same as light scattering off small particulates. But with dark background illumination and customized light beams, and without microscopes, very low concentrations of particulates very far below the threshold of visibility become visible and quantifiable because of light scattering. When combined with microscopes, the result is the ultramicroscope, which was developed later by others. Tyndall is the founder of this line of instruments, which are based on exploiting the Tyndall effect.
  • In the lab he came up with a simple way to obtain "optically pure" air. Namely, he coated the inside walls of a box with glycerin, which is a sticky syrup. He discovered that after a few days' wait, the air inside the sealed box was entirely particulate-free under examination with light beams, because the various floating-matter particulates had ended up getting stuck to the walls or settling on the sticky floor.[15] There were no signs of floating micro-organisms ("germs") in the optically pure air. He compared what happened when he let heat-sterilized meat-broths sit in such pure air, and in ordinary air. The meat-broths in the pure air remained "sweet" (as he said) to smell and taste after many months of sitting, while the ones in ordinary air started to become putrid after a few days. These demonstrations extended Louis Pasteur's earlier demonstrations that the presence of micro-organisms is a precondition for biomass decomposition. However, the next year (1876) some repeats of the exercise resulted in a surprising failure to reproduce it. From this he was led to find viable bacterial spores in supposedly heat-sterilized foods. The foods had been contaminated with dry bacterial spores from hay in the lab, he found out. All bacteria are killed by boiling but they have a spore form that can survive boiling, he correctly contended, citing research by Ferdinand Cohn. Tyndall devised a method of killing the spores that came to be known as "Tyndallization". At the time, it affirmed the "germ theory" against a number of critics whose experimental results had been defective from the same cause. During the mid-1870s Pasteur and Tyndall were in frequent communication.[16][17]
One of Tyndall's experimental apparatuses for showing that sound is reflected in air at the interface between air bodies of different densities.
  • He was the first to observe and report the phenomenon of thermophoresis in aerosols. He spotted it surrounding hot objects while investigating the Tyndall Effect with focused lightbeams in a dark room. He devised a better way to demonstrate it, and then simply reported it (1870), without investigating the physics of it in depth.[18]
  • In the late 1860s and early 1870s he wrote an introductory book and several research reports about sound propagation in air, and was one of the chief participants in a large-scale British project that developed a better foghorn. In laboratory demonstrations motivated by foghorn issues, he established that sound is partially reflected (i.e. partially bounced back like an echo) at the location where an air mass of one temperature meets another air mass of a different temperature; and more generally when a body of air contains two or more separate air masses of different densities or temperatures, the sound travels poorly because of reflections occurring at the interfaces between the air masses, and very poorly when many such interfaces are present. (He then argued, though inconclusively, that this is the usual main reason why the same distant sound, e.g. foghorn, can be heard stronger or fainter on different days or at different times of day.)[19]
  • In radiant-heat experiments that called for much laboratory expertise in the early 1860s, he showed for a variety of readily vaporizable liquids that, molecule for molecule, the vapor form and the liquid form have essentially the same power to absorb radiant heat.[20] (In modern experiments using narrow-band spectra, some relatively small differences are found that Tyndall's equipment was unable to get at; see e.g. absorption spectrum of H2O).
  • When studying the absorption of radiant heat by ozone, he came up with a demonstration that helped confirm that ozone is an oxygen cluster.[21]
  • He is credited with the first ever atmospheric pollution measurements using infrared and scattering measurement instruments to monitor a city's air quality.[citation needed]
  • Invented a better fireman's respirator, a hood that filtered smoke and noxious gas from air.
  • Tyndall’s bar breaker to demonstrate the forces of thermal expansion.

As an indicator of his lifetime research output, an index of 19th century scientific research journals has John Tyndall as the author of more than 147 papers, with practically all of them dated between 1850 and 1884, which is an average of more than four papers a year over that 35-year period.[22]

With this apparatus Tyndall observed new chemical reactions produced by high frequency light waves acting on certain vapors. The main scientific interest here, from his point of view, was the additional hard data lent to the grand question of the mechanism by which molecules absorb radiant energy.

Tyndall was an experimenter and laboratory apparatus builder, not an abstract model builder. But he did attempt to extend his studies on the heat-absorptive power of gases and vapors into a research program about molecules. That is one of the underlying agendas of his 1872 book Contributions to Molecular Physics in the Domain of Radiant Heat. It is also evident in the spirit of his widely read 1863 book Heat Considered as a Mode of Motion. Besides heat, he also saw phenomena of magnetism and sound propagation as reducible to molecular behaviors. Invisible molecular behaviors were the ultimate substrate of all physical activity. With this mindset, and his experiments, he outlined an account whereby differing types of molecules have differing absorptions of infrared radiation because their molecular structures give them differing oscillating resonances. He'd gotten into the oscillating resonances idea because he'd seen that any one type of molecule has differing absorptions at differing radiant frequencies and he was entirely persuaded that the only difference between one frequency and another is the frequency.[23] He'd also seen that the absorption behavior of molecules is quite different from that of the atoms composing the molecules — for example the gas nitric oxide absorbed more than a thousand times more infrared radiation than either nitrogen or oxygen.[24] In several kinds of experiments he showed that no matter whether a gas is a weak absorber of broad-spectrum radiant heat, it will strongly absorb the radiant heat coming from a separate body of the same type of gas.[25] That demonstrated a kinship between the molecular mechanisms of absorption and emission. Such a kinship was also in evidence in experiments by Balfour Stewart and others, cited and extended by Tyndall, that showed with respect to broad-spectrum radiant heat that molecules that are weak absorbers are weak emitters and strong absorbers are strong emitters.[26] (For example rock-salt is an exceptionally poor absorber of heat via radiation, and a good absorber of heat via conduction. When a plate of rock-salt is heated via conduction and let stand on an insulator, it takes an exceptionally long time to cool down; i.e., it's a poor emitter of infrared.) The kinship between absorption and emission was also consistent with some generic or abstract features of resonators.[27] The photochemical effect convinced Tyndall that the resonator could not be the molecule as a whole unit; it had to be some substructure, because otherwise the photochemical effect would be impossible.[28] But he was without testable ideas as to the form of this substructure, and did not partake in speculation in print. His promotion of the molecular mindset, and his efforts to experimentally expose what molecules are, has been discussed by one historian under the title "John Tyndall, The Rhetorician Of Molecularity".[29]

In his lectures at the Royal Institution Tyndall put a great value on — and was talented at producing — lively, visible demonstrations of physics concepts.[30] In one lecture, published later in one of his books, Tyndall demonstrated the propagation of light down through a stream of falling water via total internal reflection of the light. It was referred to as the "light fountain". It is historically significant today because it demonstrates the scientific foundation for modern fiber optic technology. During second half of the 20th century Tyndall was usually credited with being the first to make this demonstration. However, Jean-Daniel Colladon published a report of it in Comptes Rendus in 1842, and there's some suggestive evidence that Tyndall's knowledge of it came ultimately from Colladon and no evidence that Tyndall claimed to have originated it himself.[31]

Alpine mountaineering and glaciology

John Tyndall explored the glacial tributaries feeding Mer de Glace in 1857.

Tyndall visited the Alps in 1856 for scientific reasons and ended up becoming a pioneering mountain climber. He visited the Alps almost every summer from 1856 onward, was a member of the very first mountaineering team to reach the top of the Weisshorn (1861), and led one of the early teams to reach the top of the Matterhorn (1868). He is thus one of the names associated with the "golden age of Alpinism", i.e., the Victorian era when many of the Alpine peaks were summited for the first time.[32]

In the Alps, Tyndall studied glaciers, and especially glacier motion. His views on glacial flow brought him into dispute with others, particularly James David Forbes and Forbes's student James Thomson. Much of the early scientific work had been done by Forbes, but Forbes at that time didn't know of the phenomenon of Regelation which was discovered a little later by Micheal Faraday. Regelation played a key role in Tyndall's explanation. Forbes didn't see regelation in the same way at all. Complicating their debate, a disagreement arose publicly over who deserved to get investigator credit for what. Articulate friends of Forbes, as well as Forbes himself, thought that Forbes should get the credit for most of the good science, whereas Tyndall thought the credit should be distributed more widely. Tyndall commented: "The idea of semi-fluid motion belongs entirely to Louis Rendu; the proof of the quicker central flow belongs in part to Rendu, but almost wholly to Louis Agassiz and Forbes; the proof of the retardation of the bed belongs to Forbes alone; while the discovery of the locus of the point of maximum motion belongs, I suppose, to me."[33] When Forbes and Tyndall were in the grave, their disagreement was continued by their respective official biographers. Everyone tried to be reasonable, but agreement wasn't attained. More disappointingly, aspects of glacier motion remained not understood or not proved.

Tyndall Glacier in Chile is named after John Tyndall, as is Mount Tyndall in California[34] and Mount Tyndall in Tasmania.[35]


Tyndall's 1876 book Lessons in Electricity, which was accessible to secondary school students, demonstrated things with deliberately inexpensive and homemade equipment so that readers could do the same experiments themselves. Nevertheless during the 1880s a distributor of physics instruction equipment to American secondary schools marketed 58 separate items of hardware to accompany the book. The pictured item, an electrostatic generator, is marked "Prof. John Tyndall's Electric machine, Manufactured by Curt W. Meyer... New York". (Ref:).

Besides being a scientist, John Tyndall was a science teacher and evangelist for the cause of science. He spent a significant amount of his time disseminating science to the general public — contributing over the years to science columns in popular middle class periodicals such as the Athenaeum and the Saturday Review in the UK, and Popular Science Monthly in the USA; and giving hundreds of public lectures to non-specialist audiences at the Royal Institution. When he went on a public lecture tour in the USA in 1872, large crowds paid fees to hear him lecture about the nature of light.[36] A typical statement of Tyndall's reputation at the time is this from a London publication in 1878: "Following the precedent set by Faraday, Professor Tyndall has succeeded not only in original investigation and in teaching science soundly and accurately, but in making it attractive.... When he lectures at the Royal Institution the theatre is crowded."[37] Tyndall said of the occupation of teacher "I do not know a higher, nobler, and more blessed calling."[38] His greatest audience was gained ultimately through his books, most of which were not written for experts or specialists. He published 17 science books.[39] From the mid-1860s on, he was one of the world's most famous living physicists, due firstly to his skill and industry as a tutorialist. Most of his books were translated into German[40] and French[41] with his main tutorials staying in print in those languages for decades.

As an indicator of his teaching attitude, here are his concluding remarks to the reader at the end of a 200-page tutorial book (1872):[42] "Here, my friend, our labours close. It has been a true pleasure to me to have you at my side so long. In the sweat of our brows we have often reached the heights where our work lay, but you have been steadfast and industrious throughout, using in all possible cases your own muscles instead of relying upon mine. Here and there I have stretched an arm and helped you to a ledge, but the work of climbing has been almost exclusively your own. It is thus that I should like to teach you all things; showing you the way to profitable exertion, but leaving the exertion to you.... Our task seems plain enough, but you and I know how often we have had to wrangle resolutely with the facts to bring out their meaning. The work, however, is now done, and you are master of a fragment of that sure and certain knowledge which is founded on the faithful study of nature.... Here then we part. And should we not meet again, the memory of these days will still unite us. Give me your hand. Good bye."

As another indicator, here is the opening paragraph of his 350-page tutorial entitled Sound (1867): "In the following pages I have tried to render the science of acoustics interesting to all intelligent persons, including those who do not possess any special scientific culture. The subject is treated experimentally throughout, and I have endeavoured so to place each experiment before the reader that he should realise it as an actual operation." In the preface to the 3rd edition of this book he reports that earlier editions were translated into Chinese at the expense of the Chinese government; and translated into German under the supervision of Hermann von Helmholtz (a big name in the science of acoustics).[43] His first published tutorial, which was about glaciers (1860), similarly states: "The work is written with a desire to interest intelligent persons who may not possess any special scientific culture."

His most widely praised tutorial, and perhaps also his biggest seller, was the 550-page "Heat: a Mode of Motion" (1863; updated editions until 1880). It was in print for at least 50 years[44], and is in print today.

His three longest tutorials, namely Heat (1863), Sound (1867), and Light (1873), represented state-of-the-art experimental physics at the time they were written. Much of their contents were recent major innovations in the understanding of their respective subjects, which Tyndall was the first writer to present to a wider audience. One caveat is called for about the meaning of "state of the art". The books were devoted to laboratory science and they avoided mathematical analysis. In particular, they contain absolutely no infinitesimal calculus. Mathematical modeling using infinitesimal calculus, especially differential equations, was a component of the state-of-the-art understanding of heat, light and sound at the time.

Demarcation of science from religion

Tyndall caricatured as a preacher in Vanity Fair, 1872

The majority of the progressive and innovative British physicists of Tyndall's generation were conservative and orthodox on matters of religion. That includes for example James Joule, Balfour Stewart, James Clerk Maxwell, George Gabriel Stokes and William Thomson — all names investigating heat or light contemporaneously with Tyndall. These conservatives believed, and sought to strengthen the basis for believing, that religion and science were consistent and harmonious with each other. Tyndall, however, was a member of a club that vocally supported Darwin's theory of evolution and sought to strengthen the barrier, or separation, between religion and science. The most prominent member of this club was the anatomist Thomas Henry Huxley. Tyndall first met Huxley in 1851 and the two had a lifelong friendship. Chemist Edward Frankland and mathematician Thomas Archer Hirst, both of whom Tyndall had known since before going to university in Germany, were members too. Others included the political philosopher Herbert Spencer. See X-Club.

Though not nearly so prominent as Huxley in controversy over philosophical problems, Tyndall played his part in communicating to the educated public the virtues of having a clear separation between science (knowledge & rationality) and religion (faith & spirituality). As the elected president of the British Association for the Advancement of Science in 1874, he gave a long keynote speech at the Association's annual meeting held that year in Belfast. The speech gave a favorable account of the history of evolutionary theories, mentioning Darwin's name favorably more than 20 times, and concluded by asserting that religious sentiment should not be permitted to "intrude on the region of knowledge, over which it holds no command". This was a hot topic. The newspapers carried the report of it on their front pages — in the British Isles, North America, even the European Continent — and many critiques of it appeared soon after. The attention and scrutiny increased the friends of the evolutionists' philosophical position, and brought it closer to mainstream ascendancy.[45]

In Rome the Pope in 1864 decreed that it was an error that "reason is the ultimate standard by which man can and ought to arrive at knowledge" and an error that "divine revelation is imperfect" in the Bible — and anyone maintaining those errors was to be "anathematized" — and in 1888 decreed as follows: "The fundamental doctrine of rationalism is the supremacy of the human reason, which, refusing due submission to the divine and eternal reason, proclaims its own independence.... A doctrine of such character is most hurtful both to individuals and to the State.... It follows that it is quite unlawful to demand, to defend, or to grant, unconditional [or promiscuous] freedom of thought, speech, writing, or religion."[46] Those principles and Tyndall's principles were profound enemies. Luckily for Tyndall he didn't need to get into a contest with them, in Britain, nor in most other parts of the world. Even in Italy, Huxley and Darwin were awarded honorary medals and most of the Italian governing class was hostile to the papacy.[47] But in Ireland during Tyndall's lifetime the majority of the population grew increasingly doctrinaire and vigorous in its Roman Catholicism and also grew stronger politically. It would've been a waste of everybody's time for Tyndall to debate the Irish Catholics, but he was active in the debate in England about whether to give the Catholics of Ireland more freedom to go their own way. Like the great majority of Irish-born scientists of the 19th century he opposed the Irish Home Rule movement. He had ardent views about it, which were published in newspapers and pamphlets.[48] For example in an opinion piece in The Times on 27 Dec 1890 he saw priests and Catholicism as "the heart and soul of this movement" and wrote that placing the non-Catholic minority under the dominion of "the priestly horde" would be "an unspeakable crime".[49] He tried unsuccessfully to get the UK's premier scientific society to denounce the Irish Home Rule proposal as contrary to the interests of science.[50]

In several essays included in his book Fragments of Science for Unscientific People, Tyndall attempted to dissuade people from the belief in miracles and the effectiveness of prayers. At the same time, though, he was not broadly anti-religious, and his writings leave no straightforward evidence that he was not a Christian or at least a Deist.[51]

Private life

John Tyndall

Tyndall did not marry until age 55. His bride, Louisa Hamilton, whom he had first met in the Alps, was the 30-year-old daughter of a member of parliament (Lord Claud Hamilton, M.P.). The following year, 1877, they built a summer chalet at Belalp in the Swiss Alps. Before getting married Tyndall had been living for many years in an upstairs apartment at the Royal Institution and continued to live there after marriage until 1885 when a move was made to a house near Haslemere 45 miles southwest of London. The marriage was a happy one and without children. He retired from the Royal Institution at age 66 having complaints of ill health.

Tyndall became financially well-off from sales of his popular books and fees from his lectures (but there is no evidence that he owned commercial patents). For many years he got non-trivial payments for being a part-time scientific advisor to a couple of quasi-governmental agencies and partly donated the payments to charity. His successful lecture tour of the United States in 1872 brought him a substantial amount of dollars, all of which he promptly donated to a trustee for fostering science in America.[52] Late in life his money donations went most visibly to the Irish Unionist political cause.[53] When he died, his wealth was £22122.[54] For comparison's sake, the income of a police constable in London was about £80 per year at the time.[55]

In his last years Tyndall often took chloral hydrate to treat his insomnia. When bedridden and ailing, he died from an accidental[56] overdose of this drug at age 73, and was buried at Haslemere.[57] Afterwards, Tyndall's wife took possession of his papers and assigned herself as supervisor of an official biography of him. She dragged her feet on the project, however, and it was still unfinished when she died in 1940 aged 95.[58] The book eventually appeared in 1945, written by A. S. Eve and C. H. Creasey, whom Louisa Tyndall had authorized shortly before her death.

John Tyndall's books

  • The Glaciers of the Alps (470 pages) (1860)
  • Heat as a Mode of Motion (550 pages) (1863; revised later editions)
  • On Radiation: One Lecture (40 pages) (1865)[59]
  • Sound: A Course of Eight Lectures (350 pages) (1867; revised later editions)
  • Faraday as a Discoverer (180 pages) (1868)
  • Three Scientific Addresses by Prof. John Tyndall (75 pages) (1870)[60]
  • Notes of a Course of Nine Lectures on Light (80 pages) (1870)
  • Notes of a Course of Seven Lectures on Electrical Phenomena and Theories (50 pages) (1870)
  • Researches on Diamagnetism and Magne-crystallic Action (380 pages) (1870) (a compilation of early research reports)
  • Hours of Exercise in the Alps (450 pages) (1871)
  • Fragments of Science: A Series of Detached Essays, Lectures, and Reviews (over 500 pages) (1871; expanded later editions)
  • The Forms of Water in Clouds and Rivers, Ice and Glaciers (200 pages) (1872)
  • Contributions to Molecular Physics in the Domain of Radiant Heat (450 pages) (1872) (a compilation of research reports)
  • Six Lectures on Light (290 pages) (1873)
  • Lessons in Electricity at the Royal Institution (100 pages) (1876)
  • Essays on the Floating-matter of the Air in relation to Putrefaction and Infection (360 pages) (1881)
  • New Fragments (500 pages) (1892)

All of the above books can be freely downloaded at

Biographies of John Tyndall

  • Eve, A.S. & Creasey, C.H. (1945). Life and Work of John Tyndall. London: Macmillan.  430 pages. This is the "official" biography.
  • William T. Jeans wrote a 100-page biography of Professor Tyndall in 1887 (the year Tyndall retired from the Royal Institution). It is available here DjVu
  • Louisa Charlotte Tyndall, his wife, wrote an 8-page biography of John Tyndall that appeared in 1903 as the preface to one of his books. Available here DjVu
  • Edward Frankland wrote a 16-page biography of John Tyndall as an obituary in 1894 in a British scientific journal. The journal volume is available here DjVu
  • D. Thompson in Journal of Vocational Education & Training, volume 9:18, pages 38–48, year 1957, has an article entitled "John Tyndall (1820-1893): A study in vocational enterprise" which gives an account of Tyndall's vocational development prior to 1853. Available here.
  • Brock, W.H., et al. (1981). John Tyndall, Essays on a Natural Philosopher. Dublin: Royal Dublin Society.  220 pages.
  • Arthur Whitmore Smith, a professor of physics, wrote a 10-page biography of John Tyndall in 1920 in an American scientific monthly. Available here (page 91) DjVu
  • John Walter Gregory, a naturalist, wrote a nine-page obituary of John Tyndall in 1894 in the monthly journal "Natural Science". The journal volume is here.
  • An early, seven-page profile of John Tyndall appeared in 1864 in Portraits of Men of Eminence in Literature, Science and Art (volume II). Available here DjVu
  • A one-page profile of Tyndall, based on information supplied by Tyndall himself, appeared in 1874 in the weekly magazine Nature. Available here.
  • John Tyndall as a Mountaineer, 56-page essay by Lord Schuster. Included in Schuster's book Postscript to Adventure New Alpine Library Eyre & Spottiswoode London 1950.

See also


  1. ^ When working for the government's land surveying agency in Lancashire, Tyndall was one of a number of employees who signed a petition for higher wages plus some other working conditions changes. All of the signatories to the petition were fired. That was in November 1843. Early in 1844 he was hired by a railroad surveying company in Lancashire at almost four times higher pay than what the government had been paying him. Source: John Tyndall: A study in vocational enterprise.
  2. ^ Tyndall was the chief surveyor for the proposed railway line from Halifax to Keighley in 1846, according to Thomas Archer Hirst, who worked under Tyndall at the same engineering firm at the time ([1]). Tyndall described himself as the "principal assistant" at the firm ([2]).
  3. ^ Tyndall has detailed recollections about his life in the 1840s in "Address Delivered at the Birkbeck Institution on October 22, 1884", which is published as a chapter in his New Fragments essays (1892).
  4. ^ Queenwood College was founded by the industrialist and social philosopher Robert Owen. Reportedly Tyndall met Robert Owen more than once, and perhaps opted to work at Queenwood under Owen's influence. An account of Tyndall's acquaintance with Robert Owen is in the book "Little Journeys to the Homes of the Great, Volume 12: Great Scientists" by Elbert Hubbard, published in 1916, available at [3] (or [4]). For a different account of Tyndall's move to Queenwood, involving one George Edmondson, see Norman D. McMillan's biography of Tyndall at [5].
  5. ^ In deciding to attend the University of Marburg, the reputation of Robert Bunsen was one of the main attractions for Frankland and Tyndall. Tyndall studied under Bunsen from 1848 to 1850. Thirty-five years later, the student praised the teacher for explaining chemistry and physics in "the language of experiment" and followed that with "I still look back on Bunsen as the nearest approach to my ideal of a university teacher." [6]
  6. ^ Tyndall's main 1850's research reports on diamagnetism were later republished as a collection, which is available at In the preface to the collection Tyndall writes about the work's historical context. William T. Jeans' biography of Tyndall (pages 22 to 34) also goes into the historical context of Tyndall's diamagnetic investigations.
  7. ^ In advocating Tyndall's appointment, in a letter to the managers of the Royal Institution on 23 May 1853, Faraday also praised Tyndall's abilities as a lecturer: "I have heard him on two or three occasions, when his manner of expounding nature by discourse and experiment was in my judgement excellent". Source: [7].
  8. ^ Some of this information is taken from "Biography of John Tyndall at The Tyndall Centre for Climate Change Research". 
  9. ^ Details of Tyndall's device for measuring the infrared absorptive power of a gas are described in James Rodger Fleming (2005). Historical Perspectives on Climate Change. Oxford University Press. pp. 69–70.  (Note that what Fleming calls "spectrophotometry" is usually termed "radiometry.") Greater details are in Chapter I of Tyndall's own book Contributions to Molecular Physics in the Domain of Radiant HeatDjVu.
  10. ^ Tyndall explained the "greenhouse effect" in a public lecture in January 1863 entitled "On Radiation Through The Earth's Atmosphere". He emphasized that our environment would be much colder at nighttime in the absence of the greenhouse effect. This short, readable lecture is reprinted in his 1872 book about radiant heat, available hereDjVu.
  11. ^ The "identity of light and radiant heat" is a section heading in his 1873 tutorial Six Lectures on LightDjVu.
  12. ^ This is reported by James W. Gentry and Lin Jui-Chen in an article entitled "The Legacy of John Tyndall in Aerosol Science" published in Journal of Aerosol Science vol 27 page S503, 1996, available online at [8]. The article says that "Tyndall's primary contributions were...[among other things]... the design of experiments which increased the deflections of the galvanometer by two orders of magnitude from the earlier measurements for double refraction (by Knoblauch) and the Faraday effect (by Di la Povostaye and Desains)".
  13. ^ As reported in the 10-page biography of John Tyndall by Arthur Whitmore Smith, a professor of physics, writing in an American scientific monthly in 1920. Available hereDjVu.
  14. ^ The term Tyndall Scattering is subject to some definitional overlap with the terms Rayleigh Scattering and Mie Scattering.
  15. ^ Tyndall's book has a picture of the setup: The Floating-matter of the AirDjVu (search for the text "Fig. 2" in the book). Tyndall writes (page 46): "Gravity is not the only agent.... It is practically impossible to surround a closed vessel by an absolutely uniform temperature; and where differences of temperature, however small, exist, air-currents will be established. By such gentle currents the floating particles are gradually brought into contact with all the surrounding surfaces. To these they adhere, and the suspended matter finally disappears from the air altogether."
  16. ^ See [9] for a catalog, presumably incomplete, of letters from Pasteur to Tyndall. Their communications were most frequent during the mid-1870s. The earliest letter is dated 10 Aug 1871. Pasteur's early research had been in fermentation vats and broths. As he aimed to extend his program to air, he got in touch with Tyndall as someone who was an expert at dealing technically with air. It's probably no coincidence that in June 1871 a short lecture by Tyndall entitled "Dust and Disease" was published in the British Medical Journal. The "Dust and Disease" lecture was Tyndall's first published comments in this area in a medical journal. Ten years later Tyndall published a 350-page book Essays on the Floating-matter of the Air in relation to Putrefaction and InfectionDjVu which consists primarily of descriptions of his own experiments.
  17. ^ See also Conant, James Bryant (1957). "Pasteur's and Tyndall's Study of Spontaneous Generation". Harvard Case Histories in Experimental Science. 2. Cambridge, Massachusetts: Harvard University Press. pp. 489 – 539. 
  18. ^ For a brief history of thermophoresis studies see Encyclopedia of Surface and Colloid Science (Google Book Search preview). Thermophoresis was described by Tyndall in a Royal Institution lecture titled On Haze and Dust included in his 1870 book Scientific AddressesDjVu. He observed the thermophoresis in gas mixtures. Unrelatedly and unknown to him, thermophoresis was observed in liquid mixtures in 1856 by C. Ludwig.
  19. ^ Lord Rayleigh, who published a much-praised tome about sound in 1877-78, provides a brief review of Tyndall's original contributions to the science of sound in Proceedings of the Royal Institution (vol XIV)DjVu (dated 16 Mar 1894). Tyndall's own presentation of his "researches on the acoustic transparency of the atmosphere" is in the 3rd edition (1875) of his book SoundDjVu, Chapter VII.
  20. ^ Contributions to Molecular Physics in the Domain of Radiant Heat, pages 199-214, dated 1863. Those experiments demanded "scrupulous accuracy, and minute attention to details", he said. In one of his much simpler experiments, a lightbeam from an 1860s-vintage electric lamp was brought to a focus via a powerful concave mirror. On its way to the focus point, the lightbeam was passed through a body of liquid water. At the focus point, beyond the water, the lightbeam was able to set wood on fire but was not able to melt frozen water. On removal of the intervening body of liquid water, the frozen water rapidly melted. This indicates that frequencies emerging from water are specifically frequencies that water molecules don't absorb and water's phase state doesn't have a discernible role. (Page 314; and ref page 84).
  21. ^ Tyndall's analysis of ozone, dated January 1862, is in sections 17, 18 & 19 of Chapter II of Contributions to Molecular Physics in the Domain of Radiant HeatDjVu. For an historical context for it see The History of Ozone 1839 - 1868
  22. ^ In the later 19th century the Royal Society of London compiled an international catalog of scientific research papers, covering the whole century, indexed by author. In the Royal Society's catalog 147 entries appear under Tyndall's name between 1850 and 1883. Between 1850 and 1863 Tyndall published 74 papers in research journals, an average of nearly one every two months. A listing of these papers can be found in the Royal Society's 1872 publication Catalogue of Scientific Papers Volume VI. From 1864 through 1873 he published 41 papers, and these are listed in the Royal Society's Catalogue of Scientific Papers Volume VIII. From 1874 through 1883 he published 32 papers, and these are listed in Catalogue of Scientific Papers Volume XI. He produced very little after he got sick in 1885. Apart from his research papers, between 1860 and 1881 Tyndall also published 14 science books.
  23. ^ In early 1861 Tyndall was writing: "All the gases and vapours hitherto mentioned [which are absorbers of radiant heat] are transparent to light; that is to say, the waves of the visible spectrum pass among them without sensible absorption. Hence it is plain that their absorptive power depends on the periodicity of the undulations which strike them.... By Kirchhoff it has been conclusively shown that every atom absorbs in a special degree those waves which are synchronous with its own periods of vibration." Contributions to Molecular Physics in the Domain of Radiant HeatDjVu.
  24. ^ Contributions to Molecular Physics in the Domain of Radiant Heat, pages 80-81. He says on page 334 that the difference in absorption rates "may be a millionfold" : [abridged] "Let nitrogen and hydrogen be mixed mechanically together in the proportion of 14 : 3. Radiant heat will pass through the mixture as through a vacuum; the amount of heat intercepted is so small as to be practically insensible. The moment the nitrogen and hydrogen build themselves together into the molecules of ammonia [ NH3 ] the amount of radiant heat which they absorb is augmented more than a thousandfold. It may be a millionfold, for we do not yet know how small the absorption of the absolutely pure mixture really is. The act of chemical union is the sole cause of the enormous alteration in the amount of heat intercepted. The converse is also true: dissolve the chemical bond of the ammonia, and you instantly destroy the absorption."
  25. ^ Contributions to Molecular Physics in the Domain of Radiant Heat, sections 3 to 8 of Chap V, and sections 11 to 17 of Chap VI. Also discussed in Fragments of Science, Vol I Chap III. Tyndall said these experiments show a "principle which lies at the basis of spectrum analysis, ... namely, that a body which is competent to emit any ray, whether of heat or light, is competent in the same degree to absorb that ray." These experiments, which were reported in 1863 and 1864, were the first to show a couple of other related things and the following is a summary of one of them. In a flame of burning carbon monoxide, the carbon monoxide chemically combines with the oxygen of the air to form carbon dioxide plus heat — that much was widely known. If a body of 'cold' or room-temperature carbon dioxide is placed near the flame "the cold gas is intensely opaque to [i.e. it very strongly absorbs] the radiation from this particular flame, though it is highly transparent to [i.e. it very weakly absorbs] heat of every other kind." Thus, the bulk of the heat in the carbon monoxide flame fits the spectral profile of carbon dioxide, implying the heat is a radiant emission from the newly-formed carbon dioxide molecules. (cross-ref.) The demonstration also indicated that the carbon dioxide's spectral profile remains essentially the same at room temperature and at a temperature of over 2000 degrees Celsius, the temperature in the flame. Tyndall got the same kind of result with a flame of burning hydrogen. In Tyndall's words "the heat of these flames goes to augment the amplitude, and not to quicken the vibration". That was in contrast to the widely known observations in solids such as platinum that the spectral profile moves towards the quicker frequencies when the temperature is increased.
  26. ^ Contributions to Molecular Physics in the Domain of Radiant Heat, section 12 of chapter I, and section 6 of chapter IX. Tyndall in 1860 was first to demonstrate that visually transparent gases (such as carbon monoxide and vaporous alcohol) are infrared emitters, and when the gases were ranked by their emissive powers the rank order was the same as it was for their absorptive powers.
  27. ^ In 1853 Anders Angstrom had argued, based on general principles of resonance, that an incandescent gas should emit luminous rays of the same frequencies as those it can absorb. After this was affirmed and made more general experimentally by Tyndall and others in the 1860s, Angstrom got a lot of plaudits. When the original paper by Angstrom (published in German in 1854) was published in English in 1855, the translator from the German was John Tyndall. [10]
  28. ^ Contributions to Molecular Physics in the Domain of Radiant Heat page 428. When talking about chemical reactions produced by light in 1868 he says "if the absorption [of radiant energy] were the act of the molecule as a whole, the relative motions of its constituent atoms would remain unchanged, and there would be no mechanical cause for their separation [in a photochemical decomposition]." Therefore in a photochemical decomposition, "it is probably the synchronism of the vibrations of one portion of the molecule with the incident waves which enables the amplitude of those vibrations to augment [i.e. resonate] until the chain which binds the parts of the molecule together is snapped asunder."
  29. ^ "John Tyndall, The Rhetorician Of Molecularity", by Maria Yamalidou, published 1999, a two-part article at [11] and [12]. Also see Tyndall's popular essay "Atoms, Molecules, and Ether Waves" in Tyndall's book of essays for a broad audience New FragmentsDjVu.
  30. ^ A history paper dated 2008, John Tyndall's Lecture Courses at the Royal Institution and their Reception (pages 28 - 31) says that Tyndall and his audiences liked experimental demonstrations that had an element of spectacle, and he selected lecture topics with that consideration partly in mind. On a related point, the paper quotes the biographers Eve and Creasey: "His lectures were written down, rehersed, and profusely illustrated with experiment. He knew that a public lecture should have the same exacting care in production as a play in a theatre."
  31. ^ Daniel Colladon's 1842 "light fountain" article is entitled "On the reflections of a ray of light inside a parabolic liquid stream". For more about the history of this during the 19th century see chapter 2 of the book "The Story of Fiber Optics" by Jeff Hecht available for viewing online at Google Book Search Preview. In Tyndall's own 1870 book Notes about Light he has a section entitled "Total Reflexion" where he explains: "When the light passes from air into water, the refracted ray is bent towards the perpendicular.... When the ray passes from water to air it is bent from the perpendicular.... If the angle which the ray in water encloses with the perpendicular to the surface be greater than 48 degrees, the ray will not quit the water at all: it will be totally reflected at the surface.... The angle which marks the limit where total reflexion begins is called the limiting angle of the medium. For water this angle is 48° 27', for flint glass it is 38° 41', while for diamond it is 23° 42'."
  32. ^ According to the account in Tyndall's book The Glaciers of the Alps (1860), Tyndall in 1858 summited Monte Rosa solo carrying only a ham sandwich for sustenance. The first human summiting of Monte Rosa had taken place only in 1855. He had already summited Monte Rosa in a guided group on 10 Aug 1858 but he made an unplanned second summit solo on 17 Aug 1858 after breakfast: "the waiter then provided me with a ham sandwich, and, with my scrip thus frugally furnished, I thought the heights of Monte Rosa might be won...." (continued at pages 151-157 of Glaciers of the Alps). Besides Tyndall's own books, information about Tyndall as a mountaineer is available at A History of Mountaineering in the Alps by Claire Eliane Engel and The Victorian Mountaineers by Ronald Clark.
  33. ^ That quotation from Tyndall appears in the 1911 Encyclopedia Britannica article about Tyndall. For Forbes' view of the issue see "Appendix A" (plus Chapter XV) of Life and Letters of James David ForbesDjVu.
  34. ^ Brewer, William H. (1873). "Discovery of Mount Tyndall". The Popular Science Monthly 2: 739 – 741.,M2. 
  35. ^ Haast, Julius (1864). "Notes on the Mountains and Glaciers of the Canterbury Province, New Zealand". The Journal of the Royal Geographical Society of London 34: 87 – 96. doi:10.2307/1798467.,M2. 
  36. ^ During the 14 days in December 1872 when Tyndall gave public evening lectures in Manhattan, The New York Times printed news items about Tyndall on 9 of the days, some of them lengthy efforts at recapitulating what Professor Tyndall had said in his lecture the night before about the nature of light. The New York Times noted that more than half the people attending the lectures were women (which was generally true of Tyndall's lectures in London as well) and noted that the series of evening lectures about the nature of light delivered in Washington DC was attended by eminent U.S. Senators, Cabinet Ministers, and one night the U.S. President himself, accompanied by his daughter. The New York Times Archives, 4 Dec 1872 - 9 Feb 1873.
  37. ^ Tyndall was a celebrity in the later 19th century and he was one of the people profiled in the 1878 book Celebrities at Home (2nd Series).
  38. ^ Tyndall said he found that "two factors went to the formation of a teacher. In regard to knowledge he must, of course, be master of his work.... [and secondly] a power of character must underlie and enforce the work of the intellect. There were men who could so rouse and energise their pupils — so call forth their strength and the pleasure of its exercise — as to make the hardest work agreeable. Without this power it is questionable whether the teacher could ever really enjoy his vocation; with it, I do not know a higher, nobler, and more blessed calling." New FragmentsDjVu.
  39. ^ Some of his science books were short, like 80 pages, and others were not. See List of John Tyndall's books.
  40. ^ A catalog of the German editions of Tyndall's books is at
  41. ^ A catalog of the French editions of Tyndall's books is at
  42. ^ Quote from Tyndall's tutorial The Forms of Water in Clouds and Rivers, Ice and GlaciersDjVu.
  43. ^ Clicking this external link downloads the complete 350-page tutorial Sound, 3rd editionDjVu
  44. ^ The UK publisher was Longman. The US publisher was Appleton. Longman kept the book in print until sometime after 1908 and Appleton until sometime after 1915; see The German publisher, Braunschweig, introduced a renewed German edition in 1894; and the French publisher, Gauthier-Villars, in 1887.
  45. ^ The text of Tyndall's 1874 Belfast Address is available at This speech got more coverage in the Victorian-era newspapers than any other single public speech in the decades-long Victorian debate over the status of evolution theory. A review of the speech's reception by various London newspapers is at [13]. The great majority of London newspapers either endorsed Tyndall's position or took a neutral but respectful attitude towards it. Among other commentators the speech did have critics but a majority of these looked askance at subtleties and minor aspects (e.g., [14], [15]); only a minority defended a role for religious belief in formation of knowledge. As the London Times put it when the speech was making front-page news: "It is probably part of the great change in the manners of this country that [the speech]... will now encounter little contradiction even in the most religious circles"[16]. Among the exceptions, the Irish Catholic bishops decried it as paganism. Because the speech got widespread attention and little contradiction, and came from the Establishment post of the presidency of the British Association for the Advancement of Science, later historians have seen the speech as the "final victory" of the evolutionists in Victorian Britain ([17]).
  46. ^ Those quotations are from the Syllabus of Errors decree (1864) and the Libertas decree (1888). The Libertas decree also says: [¶27, abridged] "The divine teaching of the Church brings the sure guidance of shining light. Therefore, there is no reason why true science should feel aggrieved at having to bear the restraint of laws by which, in the judgment of the Church, human teaching has to be controlled."
  47. ^ For Italy see Prisoner in the Vatican. Also see [18].
  48. ^ For a list of Tyndall's pamphlets against Irish Home Rule see both [19] and [20]. One of the pamphlets, Mr. Gladstone's Sudden Reversal of Polarity, documented how British Prime Minister Gladstone did a flip-flop on the Home Rule question. The intent was to undermine Gladstone's intellectual credibility on the question. Gladstone publicly defended himself against the attack. The debate between them got a lot of attention in the newspapers. Tyndall was a conspicuous participant in the Irish Home Rule debate in the London newspapers between 1886 and 1893. When he died in 1893, The Times newspaper obituary noted that "our readers will remember many eloquent letters written by him of late years, full of unsparing condemnation of Mr. Gladstone's recent [Ireland] policy." ([21]).
  49. ^ More at [22]DjVu (page 183).
  50. ^ The scientists of the British Isles were nearly unanimous in opposing Irish Home Rule, but, to Tyndall's disappointment, a majority of them also thought that the matter didn't have enough direct bearing on the vital interests of science to warrant an organized formal denunciation by them. See: Jones, Greta (2001). "Scientists against Home Rule". in Boyce, D. George; O'Day, Alan. Defenders of the Union: A Survey of British and Irish Unionism Since 1801. London: Routledge. pp. 188 – 208. .
  51. ^ The collection of Tyndall's essays where his views on religion are most clearly stated is Fragments of Science Volume TwoDjVu.
  52. ^ See The New York Times, 8 July 1885. See also: Staff (1885-11-03). "Professor Tyndall's Fellowship". The New York Times (1885). 
  53. ^ See The New York Times, 25 June 1892.
  54. ^ The value of Tyndall's estate at probate was £22122 as reported in the biography of John Tyndall by W. M. Brock in Oxford Dictionary of National Biography (2004).
  55. ^ Source: page 10 of [23].
  56. ^ In late years he was taking magnesia for dyspepsia and chloral hydrate for insomnia. His wife, who administered the drugs, accidentally gave him none of the former and a lethal overdose of the latter. A newspaper report of Mrs. Tyndall's testimony at the coroner's inquest: Staff (1893-12-25). "Mrs. Tyndall's Fatal Error". The New York Times (1893). 
  57. ^ E. F. (1894). "Obituary Notice of John Tyndall" (DjVu). Proceedings of the Royal Society of London 55: xviii - xxxiv. 
  58. ^ Louisa Tyndall wanted a collaborator, but was unsatisfied with all candidates. Later, according to Crowther, she would only accept one who would live in her own house, and none such was found. Crowther, J. G. (1968). Scientific Types. London: Barrie & Rockliff, The Crescent Press Ltd.. pp. 187 – 188. 
  59. ^ The short book On Radiation (1865) was wholly incorporated into the long book Fragments of Science (1871).
  60. ^ His book Scientific Addresses was published in America only. It consisted of three speeches delivered in Britain 1868-1870. Two of the three were published in Britain in the short book Essays on the Use and Limit of the Imagination in Science.

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Up to date as of January 14, 2010

From Wikiquote

It is as fatal as it is cowardly to blink facts because they are not to our taste.

John Tyndall (August 2, 1820December 4, 1893) was an Irish physicist.



  • We have heard much of Faraday's gentleness and sweetness and tenderness. It is all true, but it is very incomplete. You cannot resolve a powerful nature into these elements, and Faraday's character would have been less admirable than it was had it not embraced forces and tendencies to which the silky adjectives "gentle" and "tender" would by no means apply. Underneath his sweetness and gentleness was the heat of a volcano. He was a man of excitable and fiery nature; but through high self-discipline he had converted the fire into a central glow and motive power of life, instead of permitting it to waste itself in useless passion.
    • Faraday as a Discoverer (1873) "Points of Character", p. 37

Scientific addresses (1870)

Knowledge once gained casts a faint light beyond its own immediate boundaries.
  • Knowledge once gained casts a faint light beyond its own immediate boundaries.
    • On the Methods and Tendencies of Physical Investigation, p. 7

Fragments of Science, Vol. II (1879)

Life is a wave, which in no two consecutive moments of its existence is composed of the same particles.
  • Life is a wave, which in no two consecutive moments of its existence is composed of the same particles.
    • Vitality
  • The mind of man may be compared to a musical instrument with a certain range of notes, beyond which in both directions we have an infinitude of silence.
    • Matter and Force
  • The brightest flashes in the world of thought are incomplete until they have been proved to have their counterparts in the world of fact.
    • Scientific Materialism
  • It is as fatal as it is cowardly to blink facts because they are not to our taste.
    • Science and Man
  • Charles Darwin, the Abraham of scientific men — a searcher as obedient to the command of truth as was the patriarch to the command of God.
    • Science and Man
  • Superstition may be defined as constructive religion which has grown incongruous with intelligence.
    • Science and Man
  • Religious feeling is as much a verity as any other part of human consciousness; and against it, on the subjective side, the waves of science beat in vain.

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1911 encyclopedia

Up to date as of January 14, 2010

From LoveToKnow 1911

JOHN TYNDALL (1820-1893), British natural philosopher, was born in Co. Carlow, Ireland, on the 2nd of August 1820, his father being the son of a small landowner in poor circumstances, but a man of more than ordinary ability. With Darwin and Huxley his name is inseparably connected with the battle which began in the middle of the 19th century for making the new standpoint of modern science part of the accepted philosophy in general life. For many years, indeed, he came to represent to ordinary Englishmen the typical or ideal professor of physics. His strong, picturesque mode of seizing and expressing things gave him an immense living influence both in speech and writing, and disseminated a popular knowledge of physical science such as had not previously existed. But besides being a true educator, and perhaps the greatest popular teacher of natural philosophy in his generation, he was an earnest and original observer and explorer of nature.

Tyndall was to a large extent a self-made man; he had no early advantages, but with indomitable earnestness devoted himself to study, to which he was stimulated by the writings of Carlyle. He passed from a national school in Co. Carlow to a minor post (1839) in the Irish ordnance survey, thence (1842) to the English survey, attending mechanics' institute lectures at Preston in Lancashire. He then became for a time (1844) a railway engineer, and in 1847 a teacher at Queenwood College, Hants. Thence with much spirit, and in face of many difficulties, he betook himself, with his colleague Edward Frankland, to the university of Marburg (1848-1851), where, by intense application, he obtained his doctorate in two years. His inaugural dissertation was an essay on screw-surfaces.

Tyndall's first original work in physical science was in his experiments with regard to magnetism and diamagnetic polarity, on which he was chiefly occupied from 1850 to 1855. While he was still lecturing on natural philosophy at Queenwood College, his magnetic investigations made him known in the higher circles of the scientific world, and through the initiative of Sir E. Sabine, treasurer of the Royal Society, he was elected F.R.S. in June 1852. In 1850 he had made Faraday's acquaintance, and shortly before the Ipswich meeting of the British Association in 1851 he began a lasting friendship with T. H. Huxley.

The two young men stood for chairs of physics and natural history respectively, first at Toronto, next at Sydney, but they were in each case unsuccessful. On the 11th of February 1853, however, Tyndall gave, by invitation, a Friday evening lecture (on "The Influence of Material Aggregation upon the Manifestations of Force") at the Royal Institution, and his public reputation was at once established. In the following May he was chosen professor of natural philosophy at the Royal Institution, a post which exactly suited his striking gifts and made him a colleague of Faraday, whom in 1866 he succeeded as scientific adviser to the Trinity House and Board of Trade, and in 1867 as superintendent of the Royal Institution. His reverent attachment to Faraday is beautifully manifested in his memorial volume called Faraday as a Discoverer (1868).

The more original contributions which Tyndall made to science are dealt with elsewhere, in the articles concerned with the various subjects (see Heat, &c.). But his inquiries into glacier motion were notable alike for his association with Switzerland and for prolonged controversy with other men of science on the subject. In 1854, after the meeting of the British Association in Liverpool, a memorable visit occurred to the Penrhyn slate quarries, where the question of slaty cleavage arose in his mind, and ultimately led him, with Huxley, to Switzerland to study the phenomena of glaciers. Here the mountains seized him, and he became a constant visitor and one of the most intrepid and most resolute of explorers; among other feats of climbing he was the first to ascend the Weiss - horn (1861). The strong, vigorous, healthfulness and enjoyment which permeate the record of his Alpine work are magnificent, and traces of his influence remain in Switzerland to this day. The problem of the flow of glaciers occupied his attention for years, and his views brought him into acute conflict with others, particularly J. D. Forbes and James Thomson. Every one knew that glaciers moved, but the questions were how they moved, for what reason and by what mechanism. Some thought they slid like solids; others that they flowed like liquids; others that they crawled by alternate expansion and contraction, or by alternate freezing and melting; others, again, that they broke and mended. Thus there arose a chaos of controversy, illuminated by definite measurements and observations. Tyndall's own summary of the course of research on the subject was as follows: The idea of semi-fluid motion belongs entirely to Rendu; the proof of the quicker central flow belongs in part to Rendu, but almost wholly to Agassiz and Forbes; the proof of the retardation of the bed belongs to Forbes alone; while the discovery of the locus of the point of maximum motion belongs, I suppose, to me.

But while Forbes asserted that ice was viscous, Tyndall denied it, and insisted, as the result of his observations, on the flow being due to fracture and regelation. All agreed that ice flowed as if it were a viscous fluid; and of this apparent viscosity James Thomson offered an independent explanation by the application of pure thermodynamical theory, which Tyndall considered inefficient to account for the facts he observed. It is unnecessary here to rake among the ashes of this prolonged dispute, but it may be noted that Helmholtz, who, in his lecture on "Ice and Glaciers," adopted Thomson's theory, afterwards added in an appendix that he had come to the conclusion that Tyndall had "assigned the essential and principal cause of glacier motion in referring it to fracture and regelation" (1865).

Tyndall's investigations of the transparency and opacity of gases and vapours for radiant heat, which occupied him during many years (1859-1871), are frequently considered his chief scientific work. But his activities were essentially manysided. He definitely established the absorptive power of clear aqueous vapour - a point of great meteorological significance. He made brilliant experiments elucidating the blue of the sky, and discovered the precipitation of organic vapours by means of light. He called attention to curious phenomena occurring in the track of a luminous beam. He examined the opacity of the air for sound in connexion with lighthouse and siren work, and he finally clinched the proof of what had been already substantially demonstrated by several others, viz. that germ-free air did not initiate putrefaction, and that accordingly "spontaneous generation" as ordinarily understood was a chimera (1875-1876). One practical outcome of these researches is the method now always adopted of sterilizing by a succession of gentle warmings, sufficient to kill the developed micro-organisms, instead of by one fierce heating attempting to attack the more refractory undeveloped germs of the same. This method of intermittent sterilization originated with Tyndall, and it was an important contribution to biological science and industrial practice.

For the substantial publication of these researches reference must be made to the Transactions of the Royal Society; but an account of many of them was incorporated in his best-known books, namely, the famous Heat as a Mode of Motion (1863; and later editions to 1880), the first popular exposition of the mechanical theory of heat, which in 1862 had not reached the textbooks; The Forms of Water, &c. (1872); Lectures on Light (1873); Floating Matter in the Air (188x); On Sound (1867; revised 1875, 1883, 1893). The original memoirs themselves on radiant heat and on magnetism were collected and issued as two large volumes under the following titles: Diamagnetism and Magne-crystallic Action (1870); Contributions to Molecular Physics in the Domain of Radiant Heat (1872).

It was on the whole the personality, however, rather than the discoverer, that was greatest in Tyndall. In the pursuit of pure science for its own sake, undisturbed by sordid considerations, he shone as a beacon light to younger men - an exemplar of simple tastes, robust nature and lofty aspirations. His elevation above the common run of men was conspicuous in his treatment of the money which came to him in connexion with his successful lecturing tour in America (1872-1873). It amounted to several thousands of pounds, but he would touch none of it; he placed it in the hands of trustees for the benefit of American science - an act of lavishness which bespeaks a noble nature. Though not so prominent as Huxley in detailed controversy over theological problems, he played an important part in educating the public mind in the attitude which the development of natural philosophy entailed towards dogma and religious authority. His famous Belfast address (1874), delivered as president of the British Association, made a great stir among those who were then busy with the supposed conflict between science and religion; and in his occasional writings - Fragments of Science, as he called them, "for unscientific people" - he touched on current conceptions of prayer, miracles, &c., with characteristic straightforwardness and vigour.

As a public speaker he had an inborn Irish readiness and vehemence of expression; and, though a thorough Liberal, he split from Mr Gladstone on Irish home rule, and took an active part in politics in opposing it.

In 1876 Tyndall married Louisa, daughter of Lord Claud Hamilton. He built in 1877 a cottage on Bel Alp above the Rhone valley, and in 1885 a house on Hindhead, near Haslemere. At the latter place he spent most of his later years; his health was, however, no longer as vigorous as his brain, and he suffered frequently from sleeplessness. On the 4th of December 1893, having been accidentally given an overdose of chloral, he died at Hindhead.

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