1708 __ Whispering Gallery — Dome of St. Paul's Cathedral in London
‣ Comment : A whispering gallery is a gallery beneath a dome or vault or enclosed in a circular or elliptical area in which whispers can be heard clearly in other parts of the building (A domed gallery in which weak sounds can be heard at great distances). A whispering gallery is usually constructed in the form of an ellipsoid, with an accessible point at each focus. When a visitor stands at one focus and whispers, the line of sound emanating from this focus reflects directly to the dish/focus at the other end of the room, and to the other person. Circular whispering galleries may provide "communication" from any part on the circumference to the diametrically-opposite point on the circumference. — The circular gallery which runs at the point where the vault of the Dome starts to curve inwards, is called the Whispering Gallery. The name comes from the fact that a person who whispers facing the wall on one side, can be clearly heard on the other, since the sound is carried perfectly around the vast curve of the Dome. The task of designing a replacement structure was officially assigned to Sir Christopher Wren in 1668, and achieved in 1708. (Compiled from various sources) — « Whispering-Gallery Phenomena at St. Paul's Cathedral. — The very curious and interesting acoustical effects observed in the Whispering Gallery under the dome of St. Paul's Cathedral have, as is well known, been explained by the late Lord Rayleigh as due to the curvilinear propagation of sound, the waves which proceed from a source placed close to the wall of the gallery clinging to its surface and creeping tan-gentially along it. This view was developed mathematically by Lord Rayleigh (Scientific Papers, vol. 5, p. 617), the theoretical conclusions arrived at being (a) that the sound-waves travel in a comparatively narrow belt skirting the wall, the thickness of this belt decreasing with the wave-length of the sound; (b) that in this belt the intensity is a maximum near the wall and decreases rapidly and continuously as we proceed radially away from it; and (c) that the intensity does not fluctuate markedly as we proceed circumferentially parallel to the wall. ». (C. V. Raman & G. A. Sutherland, In Nature, International Weekly Journal of Science, Nr 108, 08 September 1921, p. 42) — The royal family eventually installed ear shaped whispering galleries in Hastings Castle. Whispering galleries explains James A. Sellers, "are rooms whose ceilings are elliptical, a sound made at one focus of the ellipse will be reflected to the other focus (across the room), allowing people standing at the two foci to hear one another very clearly. This has been called the "whispering gallery" effect and has been used by many in the design of special rooms. In particular, St. Paul's Cathedral and one of the rooms at the United States Capitol were built with this in mind." After the War of 1812 along with several features created at Fort Adams, Rhode Island were an underground network of tunnels called listening galleries. As an existing example of the highest advances in masonry fortification wouldn't you know it, the designer of Fort Adams was a French engineer officer named Simon Bernard (1779 - 1839). Bernard, a graduate of the École Polytechnique, had served as a lieutenant general of engineers under Napoleon Bonaparte. — The principle behind whispering galleries - where words spoken softly beneath a domed ceiling or in a vault can be clearly heard on the opposite side of the chamber - has been used to achieve what could prove to be a significant breakthrough in the miniaturisation of lasers. Ultrasmall lasers, i.e., nanoscale, promise a wide variety of intriguing applications, including superfast communications and data handling (photonics), and optical microchips for instant and detailed chemical analyses. Zhang and Vahala led this collaborative research which is reported in the January 22, 2009 edition of the journal Nature. The paper is entitled: 'High-Q surface-plasmon-polariton whispering-gallery microcavity.' In addition to Zhang and Vahala, other authors of the paper were Bumki Min, Eric Ostby, Volker Sorger, Erick Ulin-Avila and Lan Yang. The prevailing theory behind why whispering galleries work (first proposed in 1871 by British astronomer George Airy to explain St. Paul's cathedral) is that sound originating at one point along the circumference of an enclosed sphere is reflected to another point along the circumference opposite the source. Vahala and his group applied this idea to dielectric microcavities, and Zhang and Min along with Ostby, Sorger and Ulin-Avila applied the idea to plasmonic microcavities. (DOE/Lawrence Berkeley National Laboratory, "Plasmonic whispering gallery microcavity paves the way to future nanolasers", In Science Centric, 24 January 2009) — Other examples : The Gol Gumbaz in Bijapur, Karnataka State, India. — Gates Circle along Delaware Ave. Buffalo, N.Y. Exterior circular concrete benches in sectors. — Selimiye Mosque in Edirne, Turkey. — The Echo Wall in the Temple of Heaven in Beijing, China. — The Fazer cafeteria in Helsinki. — The Church of the Holy Sepulcher in Jerusalem. — Statuary Hall & Ancient Hall of Representatives in the United States Capitol in Washington is a famous example of a whispering gallery. — St. Peter's Basilica in the Vatican City. — Basilica of St. John Lateran, in Rome, Italy. — Santa Maria del Fiore, Florence Cathedral, in Florence, Italy. — St Paul's Cathedral in London. — Cathedral of Brasília in Brazil. — Leaning Tower of Nevyansk in Sverdlovsk oblast. — Cincinnati Museum Center at Union Terminal. — The Mapparium in the Christian Science complex in Boston allows visitors to enter the interior of reflecting surface forming nearly complete sphere, with very striking effects. — Grand Central Station in New York City the gallery in front of the Oyster Bar restaurant. — The rotundas of the Texas State Capitol and the Missouri State Capitol. — Martello towers. — The library of Dollar Academy in Scotland. — Ali Qapu Palace in Esfahān, Iran. — Centennial fountain in front of Green Library at Stanford University in California. — Cathedral of Agrigente in Sicilia.
‣ French comment : Le premier édifice religieux à avoir été bâti sur cet emplacement est un temple dédié à Diane, au temps de Rome. On construit en 604 une première cathédrale, détruite par le feu en 1087. L'édifice est reconstruit au cours des XIème, XIIème et XIIIème siècle, mais se trouve malheureusement à nouveau la proie des flammes, celles du grand incendie de Londres de 1666. La cathédrale actuelle a été construite entre 1675 et 1710 par Christopher Wren, architecte de la Cour, en remplacement du précédent édifice. Lors de la construction de la cathédrale, Wren érige des murs pour cacher l'avancement des travaux : personne ne pouvait voir le bâtiment avant son complet achèvement sans payer. Le premier service fut célébré en 1697. Au fil des siècles, le monument a évolué, des éléments ont été ajoutés, d'autres retirés. L'élément le plus impressionnant de la cathédrale est son dôme, dont la partie supérieure s'élève à plus de cent mètres du sol, ce qui en fait l'un des plus grands dômes au monde. Cette partie de la cathédrale, soutenue par huit piliers, pèse près de soixante dix mille tonnes. La toiture, reconnaissable entre toutes par les tôles de plomb qui la recouvrent, est ornée d'une croix et d'une boule dans laquelle on pouvait autrefois pénétrer, aujourd'hui fermée pour des raisons de sécurité. On accède à cette partie du toit par un escalier de six cent marches. Sous cette boule, la Golden Gallery, est plus petite galerie du monument : la vue sur Londres depuis cette galerie est tout simplement époustouflante. Juste au-dessous d'elle se trouve la Stone Gallery, et enfin la Whispering Gallery, la salle des murmures, dont les touristes aiment tester l'acoustique très particulière. — Au-dessus de l'autel, s'élève la coupole (haute de 86 mètres sous voûte), dont la galerie qui se trouve à la base de celle-ci à 30 mètres du sol, est baptisée « galerie des murmures » (Whispering Gallery) parce qu'un mot chuchoté d'un côté s'entend distinctement au côté opposé, à plus de 34 mètres. (Compiled from various sources)
‣ Urls : http://www.youtube.com/watch?v=b42eSEdEtFs (last visited ) http://www.youtube.com/watch?v=sKQtIKzIj1c (last visited ) http://www.youtube.com/user/LondonSoundSurvey (last visited )
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