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See detailSur la cause de l'absence de coloration de certaines eaux limpides naturelles
Spring, Walthère ULiege

in Recueil des Travaux Chimiques des Pays-Bas et de la Belgique. 2e série (1898), XVII

Spring, W. Recueil des Travaux Chimiques des Pays-Bas (1898), 17, 359-75; SciFinder (Chemical Abstracts Service: Columbus, OH); https://scifinder.cas.org (accessed July 8, 2010). Compare Abstr., 1884, 259 ... [more ▼]

Spring, W. Recueil des Travaux Chimiques des Pays-Bas (1898), 17, 359-75; SciFinder (Chemical Abstracts Service: Columbus, OH); https://scifinder.cas.org (accessed July 8, 2010). Compare Abstr., 1884, 259, and Bull. Acad. roy. Belg., 1886, [iii], 12, 814, and 1897, [iii], 34, 578. Although it is well recognised that pure water is blue when viewed through a thickness greater than 1 metre, the only natural waters which appear blue are those of mountain streams which have their origin in the ice and snow of great altitudes. Berzelius has stated (Jabresbericht, 1830, 9, 207) that the extraordinarily clear water of Lake Wettern, in Sweden, is perfectly colourless when viewed through a thickness of more than 32 feet, and has hence raised objection to the view that pure water is blue. The author has previously shown (loc. cit.) that if water contains one ten-millionth part of its weight of colloidal ferric hydroxide, it no longer appears blue, but green in colour; with quantities greater than this, the colour is yellow or brown. By macerating fragments of a red rock, such as a Devonian schist, during several weeks with frequently renewed hot caustic potash, and subsequently washing with water by repeated decantation, a point is ultimately reached when the red coloring-matter ceases to subside from the washing water, even after standing several months; the particles of suspended ferric oxide (haematite) are no longer visible under a magnifying power of 150 diameters, and probably correspond with the dust of the Devonian epoch. On adding a few drops of this turbid solution to a large volume of pure water, the latter is rendered perfectly clear and colourless when viewed through a thickness of 6 metres. When the proportion of ferric oxide, however, is increased, the water quenches more and more of the transmitted light, until it finally becomes opaque, although appearing red by reflected light. These observations explain the fact that terrestrial waters rarely appear blue. That the waters of Alpine streams are generally blue is probably due to their being entirely free from suspended anhydrous ferric oxide; the cosmic dust with which they are often contaminated consists principally of meteoric iron, which possesses different optical properties from haematite, and is incapable of destroying the natural blue colour of the water. Reprinted with the permission of the American Chemical Society. Copyright © 2010. American Chemical Society (ACS). All Rights Reserved. [less ▲]

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See detailDe l'influence de l'électricité sur la sédimentation des liquides troubles
Spring, Walthère ULiege

in Bulletin de l’Académie Royale des Sciences, des Lettres et des Beaux-arts de Belgique. Sciences. 3e série (1898), XXXV(6), 780-784

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See detailSur les causes de la variété des teintes des eaux naturelles et sur la clarification des liquides par l'électricité
Spring, Walthère ULiege

in Société chimique de Belgique (Ed.) Walthère Spring : Oeuvres complètes (1898)

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See detailSur les matières colorantes à base de fer, des terrains de sédiment et sur l'origine probable des roches rouges
Spring, Walthère ULiege

in Bulletin de l’Académie Royale des Sciences, des Lettres et des Beaux-arts de Belgique. Sciences. 3e série (1898), XXXV(5), 521-545

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See detailPreuve de la nutation diurne par les écarts systématiques trouvés dans les latitudes déterminées à Lick Observatory
Folie, François ULiege

in Bulletins de l'Académie Royale des Sciences, des Lettres et des Beaux-Arts de Belgique (1897), 3e série, t. 33(4), 299-305

The author proves his theory of the diurnal nutation due to systematic differences found in the latitudes determined at Lick Observatory.

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See detailL'expression de l'heure dans le système de l'axe instantané
Folie, François ULiege

in Bulletins de l'Académie Royale des Sciences, des Lettres et des Beaux-Arts de Belgique (1897), 3e série, t. 33(5), 397-406

The author shows that the absolute uniformity of hour is the base of the spherical astronomy.

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See detailEmile du Bois-Reymond, professeur de physiologie à l'université de Berlin
Fredericq, Léon ULiege

in Bulletin de l'Académie Royale de Médecine de Belgique (1897), XI

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See detailSur une porphyroïde à Grand-Manil.
Malaise, Constantin ULiege

in Annales de la Société Géologique de Belgique (1897), 24

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See detailDécouverte de graptolites à Almaden, province de Ciudad-Réal (Espagne).
Malaise, Constantin ULiege

in Annales de la Société Géologique de Belgique (1897), 24

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See detailBenzoïque (acide)
Fredericq, Léon ULiege

in Richet, Charles (Ed.) Dictionnaire de physiologie. 002. Tome II (1897)

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See detailBiuret
Fredericq, Léon ULiege

in Richet, Charles (Ed.) Dictionnaire de physiologie. 002. Tome II (1897)

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See detailBranchie
Fredericq, Léon ULiege

in Richet, Charles (Ed.) Dictionnaire de physiologie. 002. Tome II (1897)

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See detailL'astronomie moderne
Le Paige, Constantin ULiege

Speech/Talk (1897)

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See detailNote préliminaire sur les trois périodes de la variation des latitudes
Folie, François ULiege

in Bulletins de l'Académie Royale des Sciences, des Lettres et des Beaux-Arts de Belgique (1897), 3e série, t. 34(8), 238-247

The author wants to determine his choice for the latitude variations period and introduces his theory about the diurnal nutation.

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See detailPrécis historique de la découverte de la nutation diurne
Folie, François ULiege

in Annuaire de l'Observatoire Royal de Belgique (1897), 64

The author summarizes his constants determination of the diurnal nutation and the obstacles which he had to overcome to reach his goal.

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See detailDe la nécessité d'une réaction en astronomie sphérique
Folie, François ULiege

in Bulletins de l'Académie Royale des Sciences, des Lettres et des Beaux-Arts de Belgique (1897), 3e série, t. 33(2), 154-163

The author shows without calculation that if the Oppolzer’s formulae, inaccurate according to him, are related to the instantaneous equator, the hour definition must absolutely be modified.

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See detailDe l'aberration planétaire
Folie, François ULiege

in Annuaire de l'Observatoire Royal de Belgique (1897), 64

Author’s corollaries sequence on the diurnal nutation, the latitude variations and other related phenomena.

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See detailSur l'incorrection de l'heure et de l'ascension droite déterminées dans le système de l'axe instantané
Folie, François ULiege

in Bulletins de l'Académie Royale des Sciences, des Lettres et des Beaux-Arts de Belgique (1897), 3e série, t. 33(6), 765-771

The author examines the meaning of the Oppolzer’s equations, in case they are correct, respecting the inaccuracy of the hour and of the right ascension determined in the instantaneous axis system.

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See detailRéflexions sur l'aberration planétaire
Folie, François ULiege

in Bulletins de l'Académie Royale des Sciences, des Lettres et des Beaux-Arts de Belgique (1897), 3e série, t. 33(2), 103-110

Reflections by the Author about the planetary aberration. He encourages physicists and astronomers to resume his calculations and to refute his theory if necessary.

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See detailSur des termes de nutation insensibles pour la Terre entière, sensibles pour l'écorce terrestre
Folie, François ULiege

in Bulletins de l'Académie Royale des Sciences, des Lettres et des Beaux-Arts de Belgique (1897), 3e série, t. 34(12), 1013-1019

The eulerian nutation is a very weak motion of the Earth’s axis. The author wonders what could be the meaning of this term, found by Chandler, which is considerable and which seems to indicate a period of ... [more ▼]

The eulerian nutation is a very weak motion of the Earth’s axis. The author wonders what could be the meaning of this term, found by Chandler, which is considerable and which seems to indicate a period of approximately 430 days. For him, two hypotheses are eligible. [less ▲]

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