Barometric light

Barometric light is a name for the light that is emitted by a mercury-filled barometer tube when the tube is shaken. The discovery of this phenomenon in 1675 revealed the possibility of electric lighting.

The phenomenon and its explanation

The earliest barometers were simply glass tubes that were closed at one end and filled with mercury. The tube was then inverted and its open end was submerged in a cup of mercury. The mercury then drained out of the tube until the pressure of the mercury in the tube — as measured at the surface of the mercury in the cup — equaled the atmosphere's pressure on the same surface.

In order to produce barometric light, the glass tube must be very clean and the mercury must be pure. [Even if the glass tube is clean and the mercury is pure, eventually the light will cease to appear because a thin film of mercury will form on the glass. In order to produce barometric light again, the glass must be cleaned again.] If the barometer is then shaken, a band of light will appear on the glass at the meniscus of the mercury whenever the mercury moves downward.

When mercury contacts glass, the mercury transfers electrons to the glass. Whenever the mercury pulls free of the glass, these electrons are released from the glass into the surroundings, where they collide with gas molecules, causing the gas to glow — just as the collision of electrons and neon atoms causes a neon lamp to glow. [Gay L. Dybwad and C. E. Mandeville (1967) "Generation of light by the relative motion of contiguous surfaces of mercury and glass," "Physical Review", vol. 161, pages 527-532.] [R. Budakian, K. Weninger, R. A. Hiller, S. J. Putterman (1998) Letters to "Nature" : "Picosecond discharges and slip-stick friction at a moving meniscus of mercury on glass," "Nature", vol. 391, pages 266-268. Available on-line at: http://www.physics.ucla.edu/Sonoluminescence/fricelec.pdf . Article includes photograph of barometric light occurring in a glass cylinder partially filled with mercury and low-pressure neon gas.]

History

Barometric light was first observed in 1675 by the French astronomer Jean Picard ["Experience fait à l'Observatoire sur la Barometre simple touchant un nouveau Phenomene qu'on y a découvert" [Experiment made at the [astronomical] observatory [in Paris] on a simple barometer concerning a new phenomenon that was discovered there] , "Le Journal des Sçavans" [later: "Journal des Savants" ] , page 126 (25 May 1676). Reprinted as: "Experience fait a l'observatoire sur le baromètre, touchant un nouveau phenomene que M. Picard y a decouvert" [Experiment performed at the observatory on the barometer, concering a new phenomenon that Monsieur Picard discovered there] , "Mémoires de l'Académie Royale des Sciences de Paris", vol. 10, page 566.] : "Towards the year 1676, Monsieur Picard was transporting his barometer from the Observatory to Port Saint Michel during the night, [when] he noticed a light in a part of the tube where the mercury was moving; this phenomenon having surprised him, he immediately reported it to the "Sçavans",..." ["Sur la lumière du baromètre" [On the light of the barometer] , "Histoire de l'Académie Royale des sciences de Paris",vol. 2, pages 202-203 (1694). (Available on-line at: http://books.google.com/books?id=X94EAAAAQAAJ&pg=RA1-PA102&lpg=RA1-PA102&ots=eMIuPuwM86&dq=de+la+Hire+1694+barometre+Picard&ie=ISO-8859-1&output=html .) ] [One might wonder why an astronomer would be carrying a barometer. As an astronomer, Picard measured the positions of stars, planets, etc. He knew that their apparent position in the sky is affected by atmospheric refraction. Atmospheric refraction, in turn, is affected by the air's temperature and pressure. He measured the atmospheric pressure via a barometer. See (in German): http://archimedes.mpiwg-berlin.mpg.de/cgi-bin/archim/dict/hw?lemma=Stralenbrechungen,%20a%C5%BFtronomi%C5%BFche&step=entry&id=d007 . Scroll half-way down the page to the paragraph beginning: "Picard aber erkannte schon 1669...". (from: J. S. T. Gehler, "Physicalischer Wörterbuch" [Dictionary of Physics] (5 volumes, Leipzig, 1787-1795); see entry on "Stralenbrechungen, astronomische" [astronomical refraction] .)] The Swiss mathematician Johann Bernoulli studied the phenomenon while teaching at Groningen, Holland, and in 1700 he demonstrated the phenomenon to the French Academy. [Johann Bernoulli, "Nouvelle maniere de rendre les baromètres lumineux" [New way of making barometers luminous] , "Mémoires de l'Académie Royale des Sciences de Paris", vol. 2, pages 178-190 (received 1700; published: 1703) [Available (in French) on-line at: http://ads.ccsd.cnrs.fr/docs/00/10/43/30/PDF/p178_190_vol3502m.pdf .] A summary of this article and account of Bernoulli's demonstration of the phenomenon before the Académie Royale appeared in: "Sur la lumière du baromètre" [On the light of the barometer] , "Histoire de l'Académie Royale des Sciences de Paris", pages 5-8 (1700). See also: "Histoire de l'Académie Royale des Sciences de Paris", pages 1-8 (1701).] [Johann Bernoulli, "Noveau phosphore" [New phosphorus] , "Mémoires de l'Académie Royale des Sciences de Paris", vol. 2, pages 1-9 (received: 1701; published: 1704).] ["Lettre de M. Bernoulli Professor à Groningue, touchant son noveau Phosphore" [Letter from M. Bernoulli, professor at Groningen, concerning his new phosphorus] , "Mémoires de l'Académie Royale des Sciences de Paris", vol. 2, pages 135-146 (received: 1701; published: 1704).] [Edmund N. Harvey, "A History of Luminescence: From the Earliest Times Until 1900" (Philadelphia, Pennsylvania: American Philosophical Society, 1957), pages 120, 271-277, 284, and 291.] [In his article "Nouvelle maniere...", Johann Bernoulli said that he learned of Picard's luminous barometer from the book: Joachim d'Alence, "Traittez de Barométres, Thermométres, et Notiométres, ou Hygrométres" (Amsterdam, Netherlands: Henry Wetstein, 1688), pages 50-52.] After learning of the phenomenon from Bernoulli, the Englishman Francis Hauksbee [Francis Hauksbee, "Several experiments on the mercurial phosphorus, made before the Royal Society, at Gresham-College," "Philosophical Transactions of the Royal Society of London", vol. 24, pages 2129-2135 (1704-1705).] investigated the subject extensively. Hauksbee showed that the full vacuum was not essential to the phenomenon, for the same glow was apparent when mercury was shaken with air only partially rarefied, and that even without using the barometric tube, bulbs containing low-pressure gases could be made to glow via externally applied static electricity. The phenomenon was also studied by a contemporary of Hauksbee's, the Frenchman Pierre Polinière. [Pierre Polinière, "Expériences de physique" [Experiments in Physics] (Paris: J. de Laulne, 1709), pages 39-42. (Available on-line at: http://books.google.com/books?id=fgQ5AAAAMAAJ&pg=RA3-PA39&vq=vif+argent&dq=pierre+poliniere+barometre+lumiere&ie=ISO-8859-1&output=html .] [David Corson, "Pierre Polinière, Francis Hauksbee, and Electroluminescence: A case of simultaneous discovery," "Isis", vol. 59, no. 4, pages 402-413 (Winter 1968).] [Gabriel-Philippe de la Hire, a French mathematician, also studied the phenomenon. See: Gabriel-Philippe de la Hire, "Remarque sur quelques experiences faites avec plusieurs barometres, et sur la lumiere que fait un de ceux dont on s'est servi en l'agitant verticalement," "Mémoires de l'Académie Royale des Sciences de Paris", pages 226-228 (12 July 1705). (Available on-line at: http://ads.ccsd.cnrs.fr/docs/00/10/97/48/PDF/p226_228_vol3487m.pdf .) Others who investigated barometric light include: (1) Du Tal, "Pièce justificative pour M. Bernoulli contra Messieurs de l'Académie Royale des Sciences en faveur du phosphore, qu'il a proposé à cette Académie," "Nouvelles de la République des Lettres", vol. 40, pages 243-255 (September 1706); (2) Johann Michael Heusinger, “Disertatio de noctiluca mercuriali sive de luce quam argentum virum in tenebris fundit…” (Giessen, Germany: Muller, 1716) ; (3) Jean-Jacques Dortous de Mairan, "Sur la cause de la lumière des phosphores et des notiluques" (Bordeaux, France: 1717); (4) Wilhelm Bernard Nebel, "Dissertatio physica de mercurio lucente in vacuo sub praesidio J. Bernoulli" (Basil, Switzerland: 1719); (5) Charles François de Cisternay du Fay, “Sur les barometres lumineux,” "Histoire de l’Académie Royale des sciences de Paris", pages 13 ff; also printed in: "Mémoires de l’Académie Royale des sciences de Paris", pages 295-306 (1723); (6) Anders Celsius, “Observatio de lumine in barometro,” "Acta Literaria et Scientiarum Sueciae", vol. I, pages 601 ff (1734); (7) Johann Heinrich Winkler, "Gedanken von den Eigenschaften, Wirkungen und Ursachen der Electricität, nebst einer Beschreibung zwo neuer electrischen Maschinen" [Thoughts on the properties, effects, and causes of electricity, together with a description of two new electrical machines] (Leipzig, Germany: Bernhard Christoph Breitkopfs, 1744); (8) Christian Friedrich Ludolff, le jeune, “Sur l’electricité des barometres,” "Mémoires de l’Académie Royale des Sciences et des Belles-Lettres de Berlin (Class physique)", vol. I.b, pages 3-13 (1745); (9) Abraham Trembley, "Part of a letter from Mr. Trembley, F.R.S. to Martin Folkes, Esq., Pres. R.S. concerning the light caused by quicksilver shaken in a glass tube, proceeding from electricity," "Philosophical Transactions of the Royal Society of London", vol. 44, pages 58-60 (1746-1747); (10) Giovanni Battista Beccaria, "Dell'Elettricismo Artificale, e Naturale" (Turin, Italy: Filippo Antonio Campana, 1753); (11) Franciscus Ulricus Theodorus Aepinus, “De electricitate barometrorum disquisitio,” "Novi Commentarii Academiae Scientiarum Imperialis Petropolitanae" [New Memoirs of the Imperial Academy of Sciences at St. Petersburg] , vol. 12, pages 28-31 (1768).]

Footnotes

External links

* [http://xnet.rrc.mb.ca/janaj/history.htm History of the development of the concept of the electric charge]

References

*1911